Co-reporter:Tang Zhu, Chao Cai, Jing Guo, Rong Wang, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces March 22, 2017 Volume 9(Issue 11) pp:10224-10224
Publication Date(Web):March 2, 2017
DOI:10.1021/acsami.7b00149
Polypropylene (PP), including isotactic PP (i-PP) and atactic PP (a-PP) with distinct tacticity, is one of the most widely used general plastics. Herein, ultra water repellent PP coatings with tunable adhesion to water were prepared via a simple casting method. The pure i-PP coating shows a hierarchical morphology with micro/nanobinary structures, exhibiting a water contact angle (CA) larger than 150° and a sliding angle less than 5° (for 5 μL water droplet). In contrast, the pure a-PP coating has a less rough morphology with a water contact angle of about 130°, and the water droplets stick on the coating at any tilted angles. For the composite i-PP/a-PP coatings, however, ultra water repellency with CA > 150° but water adhesion tailorable from slippery to sticky can be realized, depending on the contents of a-PP and i-PP. The different wetting behaviors are due to the various microstructures of the composite coatings resulting from the distinct crystallization ability of a-PP and i-PP. Furthermore, the existence of a-PP in the composite coatings enhances the mechanical properties compared to the i-PP coating. The proposed method is feasible to modify various substrates and potential applications in no-loss liquid transportation, slippery surfaces, and patterned superhydrophobic surfaces are demonstrated.Keywords: adhesion; crystallization; microstructure; polypropylene; water repellent;
Co-reporter:Wen-Xing Liu, Chi Zhang, Huan Zhang, Ning Zhao, Zhi-Xiang Yu, and Jian Xu
Journal of the American Chemical Society June 28, 2017 Volume 139(Issue 25) pp:8678-8678
Publication Date(Web):May 30, 2017
DOI:10.1021/jacs.7b03967
Polyurethanes (PUs) have many applications resulting from their preeminent properties, but being commonly used toxic catalysts, and the lack of processability for PU thermosets cause limitations. Herein, we report a new class of the PU-like dynamic covalent polymers, poly(oxime-urethanes) (POUs), which are prepared from the uncatalyzed polyaddition of multifunctional oximes and hexamethylene diisocyanate (HDI) at ambient temperature. Kinetics studies reveal that almost complete polymerization (∼99% conversion) can be achieved in 3 h at 30 °C in dichloromethane (DCM), the most effective among the solvents evaluated, producing linear POUs with comparable molecular weights to the catalyzed PUs. We find that the oxime-carbamate structures are reversible at about 100 °C through oxime-enabled transcarbamoylation via a thermally dissociative mechanism. The cross-linked POUs based on oxime–carbamate bonds show efficient catalyst-free healable/recyclable properties. Density functional theory (DFT) calculations suggest that the fast oxime-urethanation and the mild thermoreversible nature are mediated by the characteristic nitrone tautomer of the oxime. Given widespread urethane-containing materials, POUs are of promising potential in applications because of the excellent mechanical performances, facile preparation, and dynamic property without using catalysts.
Co-reporter:Dongdong Li, Heng Shen, Chao Cai, Tongbing Sun, Yiping Zhao, Li Chen, Ning Zhao, and Jian Xu
ACS Omega April 2017? Volume 2(Issue 4) pp:1738-1738
Publication Date(Web):April 28, 2017
DOI:10.1021/acsomega.7b00039
Catkin, a natural hollow fiber, is used as a template to fabricate light, flexible, and electrically conductive silver microtubes with a high aspect ratio. The template is functionalized with tannic acid (TA)–Fe coordination complexes. Because of the metal ion chelating ability and reducibility of TA, silver nanoparticles (Ag NPs) can be formed in situ on the fiber’s surface. The as-formed Ag NPs can act as nucleation sites in subsequent electroless silver plating, leading to the formation of a compact and uniform silver coating on the microtube. The coating is constructed by densely packed Ag NPs of only 15 ± 5 nm in diameter. Because of the tight accumulation and small size of the Ag NPs, the resulting silver-coated microtubes, without any post-treatment, show an electrical resistivity of 1500 mΩ·cm at a bulk density of 0.6 g·cm–3. We find that the in situ formed nucleation sites and the stirring speed in the electroless plating play important roles in the formation of a silver coating with a high electrical conductivity. This method may be extended to fabricate conductive nanocoatings on other substrates.Topics: Coating materials; Deposition process; Electric properties; Electric transport processes and properties; Organic compounds and Functional groups;
Co-reporter:Wei-wei Li;Hong-liang Kang 徐坚
Chinese Journal of Polymer Science 2017 Volume 35( Issue 6) pp:764-772
Publication Date(Web):23 April 2017
DOI:10.1007/s10118-017-1922-9
The microcrystalline structure and microvoid structure in carbon fibers during graphitization process (2300−2700 °C) were characterized employing laser micro-Raman scattering (Raman), X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and high-resolution transmission electron microscopy (HR-TEM). The crystalline sizes (La, Lc) increased and interlayer spacing (d002) decreased with increasing heat treatment temperature (HTT). The microvoids in the fibers grew up and contacted to the neighbors with the development of microcrystalline. In addition, the preferred orientation of graphite crystallite along fiber axis decreased and microvoids increased. The results are crucial for analyzing the evolution of microstructure of carbon fibers in the process of heat treatment and important for the preparation of high strength and high modulus carbon fibers.
Co-reporter:Sheng Zhou, Mengyao Zhang, Rong Wang, Jing Ping, Xiaoli Zhang, Ning Zhao, Jian Xu, Zhihao Shen, Xinghe Fan
Polymer 2017 Volume 109() pp:49-57
Publication Date(Web):27 January 2017
DOI:10.1016/j.polymer.2016.12.036
•The introduction of bulky m-triphenyl pendant group to the aramids can fabricate organo-soluble polymers.•The molecular weights of the aramids can be characterized by GPC. Glass transitions of some polymers are observed.•These aramids possess lyotropic liquid crystalline properties.Two monomers o-(m-triphenyl)-terephthaloyl chloride (TPH1-COCl) and m-(m-triphenyl)- isophthaloyl chloride (TPH2-COCl) with bulky pendant groups were prepared, and they were polymerized with p-phenylenediamine (PPD) or copolymerized with PPD and terephthaloyl chloride (TPC) to prepare aromatic polyamides which were named TPH1 polymer and TPH2 polymer, respectively. The structures of the monomers with bulky pendant groups and the polymers were characterized by 1H NMR and gel permeation chromatography. The resulting polymers are soluble in some organic solvents such as N-methyl-2-pyrrolidone. However, the solubility of the two series of polymers was different due to the different structures of the two monomers, and it is affected by the feeding ratio of the monomers. Both kinds of polymers have good thermal stabilities with 5% weight loss temperatures close to 500 °C. And glass transitions of some TPH2 polymers were observed. Most of these polyamides show lyotropic liquid crystalline (LLC) behaviors as evidenced by polarized light microscopy results. And the LLC properties are influenced by the structures, molecular weights, and concentrations of the polymers.
Co-reporter:Ke-Jian Cui;Cai-Zhen Zhu;Huan Zhang;Qin Xuan;Wei-Zhi Zou;Zhi-Yan Zhang;Xue-Chun Lin;Ning Zhao
Journal of Materials Chemistry C 2017 vol. 5(Issue 46) pp:12035-12038
Publication Date(Web):2017/11/30
DOI:10.1039/C7TC04303A
Herein, a promising application of blue LD-initiated photosensitive resins in 3D printing is developed. Compared with traditional UV 3D printing, a safer and inexpensive light source, higher polymerization efficiency, and more available precursors are presented.
Co-reporter:Rong Wang, Yuhua Long, Tang Zhu, Jing Guo, Chao Cai, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2017 Volume 498(Volume 498) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.jcis.2017.03.035
Wrinkles exist widely in nature and our life. In this paper, wrinkles on polydopamine (PDA)/polystyrene (PS) bilayer films were formed by thermal annealing due to the different thermal coefficients of expansion of each layer. The factors that influenced the dimensions of wrinkles were studied. We found that oriented wrinkles could be formed if the bilayer films were patterned with micro-grooves, and the degree of the orientation depended on the thickness of the PDA and the dimensions of the grooves. Combined with the strong adhesion, biocompatibility and reactivity of PDA, the oriented wrinkles on PDA/PS patterned bilayers may find potential application in diffraction gratings, optical sensors and microfluidic devices.Download high-res image (45KB)Download full-size image
Co-reporter:Dong Wang;Huan Zhang;Jing Guo;Beichen Cheng;Yuan Cao;Shengjun Lu;Ning Zhao
Macromolecular Rapid Communications 2016 Volume 37( Issue 7) pp:655-661
Publication Date(Web):
DOI:10.1002/marc.201500637
Co-reporter:Junjie Wu, Chao Cai, Zhou Zhou, Hui Qian, Fanglin Zha, Jing Guo, Bing Feng, Tiexiang He, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2016 Volume 463() pp:214-221
Publication Date(Web):1 February 2016
DOI:10.1016/j.jcis.2015.10.056
•A uniform, compact and thermal stable biomimetic coatings was obtained.•The coating exhibits superior long-term anti-corrosion properties.•The hydrophobicity, good stability and strong wet adhesion endow the remarkable properties.A low-cost mussel inspired approach was developed to produce anti-corrosion coating on copper substrate. Catechol (CA) and polyamine (PA) were spontaneously polymerized to form adhesive coating of poly(cetechol/polyamine) (P(CA/PA)) onto copper surface and then P(CA/PA) was grafted by 1-dodecanethiol. The SEM, contact angle, XPS, FTIR and TG results demonstrated the formation of uniform, compact and thermal stable coatings through multiple interactions and chemically grafting. Electrochemical tests indicated of Cu-P(CA/PA)-SH possessed a highest corrosion potential of −81 mV, a lowest corrosion current density of 0.15 μA/cm2, and a highest coating resistance of 57.19 kΩ cm2, and also exhibit great long-term stability whether in solution immersion or salt spray tests. The remarkable anti-corrosion capability of Cu-P(CA/PA)-SH could be ascribed to the synergistic effect of the hydrophobicity, good stability, and strong wet adhesion of the mussel-inspired coating. This study provides an effective and cheap way for material protection and may give inspiration in the fields of material, biology and medicine relating to surface and interface engineering.
Co-reporter:Heng Shen, Chao Cai, Jing Guo, Zhenchao Qian, Ning Zhao and Jian Xu
RSC Advances 2016 vol. 6(Issue 20) pp:16489-16494
Publication Date(Web):29 Jan 2016
DOI:10.1039/C6RA00980H
Thermal interface materials are widely used in thermal management, and usually require a high thermal conductivity, low coefficient of thermal expansion (CTE) and adequate softness. Herein, hBN/PDMS composites are fabricated by the infiltration of a PDMS prepolymer in the hBN scaffolds followed by a thermal curing process. The scaffolds are prepared by an ice templating method with hBN microplatelets, leading to a good alignment of hBN platelets along the z direction in the PDMS matrix. This unique structure results in a high thermal conductivity, which is about 3 times higher than that of the composites fabricated by a casting method, and the thermal conductivity is as high as 1.4 W m−1 K−1 along the z direction at ∼20 wt% of hBN microplatelets. The composites also possess low CTEs which are <100 ppm K−1 along the z direction and maintain an adequate softness.
Co-reporter:Zhen Wang, Zhenchao Qian, Yuan Cao, Xiangzhi Zhang, Renzhong Tai, Haixia Dong, Ning Zhao and Jian Xu
RSC Advances 2016 vol. 6(Issue 26) pp:21571-21576
Publication Date(Web):17 Feb 2016
DOI:10.1039/C5RA22733J
Creating hollow structures in microspheres is attracting increasing interest because of the notable large capacity, high porosity, low density and extended surface area of the hollow microspheres prepared. Herein, facile preparation of bridged silsesquioxane (BSQ) microspheres with interconnected multi-cavities and open-hole structures is presented. The well-developed multi-cavities are derived from the configuration of the water-in-oil-in-water emulsion of the precursor. The condensation of the precursor in the emulsion results in the transition of the liquid precursor to solid BSQ resin, which preserves the emulsion structure and induces the formation of voids. The resultant hollow BSQ microspheres show advantages in controllable cargo delivery.
Co-reporter:Dong Wang;Huan Zhang;Beichen Cheng;Zhenchao Qian;Wenxing Liu;Ning Zhao
Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 10) pp:1357-1366
Publication Date(Web):
DOI:10.1002/pola.27983
ABSTRACT
A facile cross-linking strategy of using small molecules as physcial crosslinkers to facilitate recyclable polybutadiene (PB) elastomer with excellent toughness and stretchability is demonstrated. Carboxylic acid groups were incorporated along the PB backbone via thiol-ene reaction, and then the polymer can be cross-linked by ionic hydrogen bonds between the carboxylic acid groups from PB and the amine groups of the cross-linkers. The ionic hydrogen bonds can dynamiclly break and reconstruct upon deformation, thus endowing the resultant polymer with not only high toughness and stretchability (∼1800%), but also good self-recovery and enhanced damping properties. Remarkably, the dynamically cross-linked PB elastomer can be thermally recycled owing to the thermal reversibility of the ionic hydrogen bonds and the mechanical properties can be largely recovered after reprocessing. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1357-1366
Co-reporter:Yi Hou;Chun-ting Duan;Ning Zhao 赵宁;Huan Zhang
Chinese Journal of Polymer Science 2016 Volume 34( Issue 10) pp:1234-1239
Publication Date(Web):2016 October
DOI:10.1007/s10118-016-1828-y
Separation of oil/water mixtures, especially for the emulsified oil/water mixtures, is important because of the frequent occurrence of oil spill accidents. Utilizing superwetting porous membrane has become a promising approach to separate either surfactant-free or surfactant-stabilized emulsions. Herein we report a facile and versatile strategy for preparing hydrophobic/under-oil superhydrophobic membranes by coating the skeletons of the membranes with the poly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS) nanoparticles. The obtained membranes could be used to separate various waterin- oil emulsions with high flux and separation efficiency. In addition, owning to the outstanding resistance of PTFPMS to the most organic solvents or oils, the modified membranes exhibited the excellent reusability and the antifouling properties that were critical in the practical applications. Many commercially available membranes can be modified by such a simple method.
Co-reporter:Dong Wang, Jing Guo, Huan Zhang, Beichen Cheng, Heng Shen, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 vol. 3(Issue 24) pp:12864-12872
Publication Date(Web):11 May 2015
DOI:10.1039/C5TA01915J
A strategy for combining covalent and non-covalent cross-links to construct multifunctional rubber materials with intelligent self-healing and shape memory ability is demonstrated. Rubbers were prepared by self-assembly of complementary polybutadiene oligomers bearing carboxylic acid and amine groups through reversible ionic hydrogen bonds via the acid–base reaction, and then further covalently cross-linked by tri-functional thiol via the thiol-ene reaction. The resulting polymers exhibit self-healing and shape memory functions owing to the reversible ionic hydrogen bonds. The covalent cross-linking density can be tuned to achieve tailorable mechanical and stimuli-responsive properties: a low covalent cross-linking density maintains the remarkable self-healing capability of rubber at ambient temperature without any external stimulus, while a high covalent cross-linking density improves the mechanical strength and induces shape memory behavior, but effective self-healing needs to be triggered at high temperature. This strategy might open a promising pathway to fabricate intelligent multifunctional polymers with versatile functions.
Co-reporter:Heng Shen, Chunting Duan, Jing Guo, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 vol. 3(Issue 32) pp:16663-16669
Publication Date(Web):09 Jul 2015
DOI:10.1039/C5TA04188K
An environmentally friendly and facile approach was developed to synthesize boron nitride nanosheet/Ag nanoparticle hybrids (BNNS/Ag) in aqueous solution at room temperature without additional reductants. BNNSs were modified with a thin layer of tannic acid–ferric ion (TA–Fe) complex. Silver nanoparticles with a uniform diameter of approximately 7 nm were in situ formed on the surface of the modified BNNSs due to the strong reducibility of TA. The resultant nanohybrids showed excellent catalytic activity in reduction of 4-nitrophenol. BNNS/Au and BNNS/Pd nanohybrids can also be fabricated by this means, implying its extensive promise in catalytic, bio-medical and sensing fields.
Co-reporter:Yi Hou, Zhen Wang, Jing Guo, Heng Shen, Huan Zhang, Ning Zhao, Yiping Zhao, Li Chen, Songmiao Liang, Yan Jin and Jian Xu
Journal of Materials Chemistry A 2015 vol. 3(Issue 46) pp:23252-23260
Publication Date(Web):06 Oct 2015
DOI:10.1039/C5TA05612H
Utilizing superhydrophobic porous materials in oil/water separation has attracted increasing research interest, however, most of these materials are usually complicated to fabricate or easily lose their functions in harsh circumstances. In this study, dispersion of poly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS) micro–nano aggregations in acetone/water was facially prepared via a simple phase separation method. The aggregations can be easily coated on the skeletons of various 2D and 3D porous substrates, endowing the porous materials with superhydrophobicity. The prepared superhydrophobic materials show excellent resistance to chemical erosion, mechanical abrasion, and high temperature (up to 400 °C). This robust superhydrophobicity promises application of the resultant porous materials in harsh environments, and examples of using these superhydrophobic porous materials to separate oil/water mixtures have been demonstrated. This simple and universal method is suitable for the large-scale preparation of porous materials with robust superhydrophobicity.
Co-reporter:Chao Cai, Xiaoli Yang, Zhen Wang, Haixia Dong, Hongwei Ma, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 vol. 3(Issue 17) pp:4254-4259
Publication Date(Web):30 Mar 2015
DOI:10.1039/C5TC00357A
This paper demonstrates a facile and effective improvement of abrasion resistance of silica nanoparticle (NP) based anti-reflective coatings via capillary condensation of 3-aminopropyl triethoxysilane (APTES). The quartz crystal microbalance (QCM) is used to test the abrasion resistance property. The versatility of this developed method is further illustrated by the successful application to the poor heat-resistant polymer substrates.
Co-reporter:Heng Shen, Jing Guo, Hao Wang, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 10) pp:5701
Publication Date(Web):February 24, 2015
DOI:10.1021/am507416y
With the development of microelectronic technology, the demand of insulating electronic encapsulation materials with high thermal conductivity is ever growing and much attractive. Surface modification of chemical inert h-BN is yet a distressing issue which hinders its applications in thermal conductive composites. Here, dopamine chemistry has been used to achieve the facile surface modification of h-BN microplatelets by forming a polydopamine (PDA) shell on its surface. The successful and effective preparation of h-BN@PDA microplatelets has been confirmed by SEM, EDS, TEM, Raman spectroscopy, and TGA investigations. The PDA coating increases the dispersibility of the filler and enhances its interaction with PVA matrix as well. Based on the combination of surface modification and doctor blading, composite films with aligned h-BN@PDA are fabricated. The oriented fillers result in much higher in-plane thermal conductivities than the films with disordered structures produced by casting or using the pristine h-BN. The thermal conductivity is as high as 5.4 W m–1 K–1 at 10 vol % h-BN@PDA loading. The procedure is eco-friendly, easy handling, and suitable for the practical application in large scale.Keywords: aligned structure; hexagonal boron nitride; polydopamine; thermal conductivity
Co-reporter:Zhen Wang, Dong Wang, Zhenchao Qian, Jing Guo, Haixia Dong, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 3) pp:2016
Publication Date(Web):January 5, 2015
DOI:10.1021/am5077765
Aerogels are a family of highly porous materials whose applications are commonly restricted by poor mechanical properties. Herein, thiol-ene chemistry is employed to synthesize a series of novel bridged silsesquioxane (BSQ) precursors with various alkoxy groups. On the basis of the different hydrolyzing rates of the methoxy and ethoxy groups, robust superhydrophobic BSQ aerogels with tailorable morphology and mechanical performances have been prepared. The flexible thioether bridge contributes to the robustness of the as-formed aerogels, and the property can be tuned on the basis of the distinct combinations of alkoxy groups with the density of the aerogels almost unchanged. To the best of our knowledge, the lowest density among the ambient pressure dried aerogels is obtained. Further, potential application of the aerogels for oil/water separation and acoustic materials has also been presented.Keywords: aerogel; alkoxy group; bridged silsesquioxane; oil/water separation; robustness
Co-reporter:Tang Zhu, Chao Cai, Chunting Duan, Shuai Zhai, Songmiao Liang, Yan Jin, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 25) pp:13996
Publication Date(Web):June 10, 2015
DOI:10.1021/acsami.5b03056
A simple, rapid (10 s) and scalable method to fabricate superhydrophobic polypropylene (PP) fabrics is developed by swelling the fabrics in cyclohexane/heptane mixture at 80 °C. The recrystallization of the swollen macromolecules on the fiber surface contributes to the formation of submicron protuberances, which increase the surface roughness dramatically and result in superhydrophobic behavior. The superhydrophobic PP fabrics possess excellent repellency to blood, urine, milk, coffee, and other common liquids, and show good durability and robustness, such as remarkable resistances to water penetration, abrasion, acidic/alkaline solution, and boiling water. The excellent comprehensive performance of the superhydrophobic PP fabrics indicates their potential applications as oil/water separation materials, protective garments, diaper pads, or other medical and health supplies. This simple, fast and low cost method operating at a relatively low temperature is superior to other reported techniques for fabricating superhydrophobic PP materials as far as large scale manufacturing is considered. Moreover, the proposed method is applicable for preparing superhydrophobic PP films and sheets as well.Keywords: fabrics; polypropylene; recrystallization; superhydrophobic; swelling;
Co-reporter:Chunting Duan, Tang Zhu, Jing Guo, Zhen Wang, Xiaofang Liu, Hao Wang, Xun Xu, Yan Jin, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 19) pp:10475
Publication Date(Web):April 28, 2015
DOI:10.1021/acsami.5b01901
The separation and removal of oil or organic pollutants from water is highly imperative. The oil phases in surfactant-free oil-in-water emulsions or in free oil/water mixtures can be smartly enriched and transported by using superhydrophobic/superoleophilic iron particles (SHIPs) under a magnetic field. For water-in-oil emulsion, SHIPs-based composite membranes selectively allow the oil to pass through. Their convenient and scalable preparation, excellent separation performance, and good reusability are of great advantages for practical applications in wastewater treatment, the cleanup of oil spills, emulsion concentration, and fuel purification.Keywords: magnetic particles; nanostructured; oil/water separation; superhydrophobicity; superoleophilicity;
Co-reporter:Huichao Liu, Jinghong Ma, Jinghua Gong, Jian Xu
Journal of Non-Crystalline Solids 2015 Volume 419() pp:92-96
Publication Date(Web):1 July 2015
DOI:10.1016/j.jnoncrysol.2015.03.040
•The SnF2–SnO–P2O5 glasses with low glass transition temperature (Tg) were prepared.•The composition and melting time play an important role on the properties of the glasses.•The relation between properties and structure of the glasses was studied.SnF2–SnO–P2O5 glasses with low glass transition temperature (Tg) were prepared in this paper. The effect of composition and melting time on the properties of these glasses was studied. X-ray diffraction (XRD) indicated that these prepared samples were glasses regardless of the composition and melting time. The properties of these glasses such as Tg, dilatometric softening temperature (Tf), thermal expansion coefficient (α) and density (ρ) were tested. The structure of these glasses was studied by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA). The glasses' structure and network dimension were supposed to play a critical role on the properties of the glasses. The fluorine and hydroxyl can decrease the network dimension of the glasses and thus decrease the Tg values. While, the oxidation of Sn2 + to form the Sn4 + could increase the network dimension of glasses and thus increase the Tg values.
Co-reporter:Huichao Liu, Jinghong Ma, Jinghua Gong, Jian Xu
Thermochimica Acta 2015 Volume 613() pp:1-8
Publication Date(Web):10 August 2015
DOI:10.1016/j.tca.2015.05.014
•Pglass is an inorganic polymer with low Tg and mutable viscosity.•Kinetics models and activation energy can be used to analyze the process.•Pglass can play different effect on the crystallization process of PET.The physical state of phosphate glass (Pglass) has an influence on the non-isothermal crystallization behaviors of PET matrix in the PET/Pglass blends, which has been investigated via heating the glassy state and cooling the melt state of the blends at various scanning rates, respectively, by means of differential scanning calorimetry (DSC) technique. The kinetics models based on the Avrami and Mo equations were used to analyze the non-isothermal crystallization process. Furthermore, the activation energy of non-isothermal crystallization, according to Kissinger theory for heating process and Friedman theory for cooling process, has been evaluated. The results showed that the Pglass accelerated the non-isothermal cold crystallization rate of PET matrix due to its nucleation effect. In contrast, for the non-isothermal melt crystallization, the Pglass hindered the crystallization process due to its large melt viscosity.
Co-reporter:Heng Shen;Yuhua Long;Xiaoli Yang;Ning Zhao
Polymer International 2015 Volume 64( Issue 8) pp:986-991
Publication Date(Web):
DOI:10.1002/pi.4913
Abstract
A facile method of fabricating metal oxide hollow spheres using polydopamine (PDA) nanoparticles as active templates is reported. Monodisperse PDA nanoparticles were prepared by the polymerization of dopamine in Tris buffer solution containing various amounts of poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO-PPO-PEO). The diameter of the resultant PDA nanoparticles decreased from about 180 to 80 nm with an increase of PEO-PPO-PEO concentration from 0 to 1.25 mg mL−1. The active groups of PDA and also the PEO-PPO-PEO adsorbed on the PDA spheres can chelate with various metal ions. It was found that when PDA spheres with diameter below 100 nm were used as templates, diverse metal oxide hollow spheres like CeO2, NiO and Cr2O3 could be obtained after calcination, demonstrating the diversity of this method for fabricating various metal oxide hollow spheres. © 2015 Society of Chemical Industry
Co-reporter:Zhen Wang;Zhen Dai;Ning Zhao;Xiaoli Zhang
Journal of Sol-Gel Science and Technology 2015 Volume 75( Issue 3) pp:519-529
Publication Date(Web):2015 September
DOI:10.1007/s10971-015-3722-4
A novel bridged silsesquioxane (BSQ) monomer was synthesized from 3-(2,3-epoxypropoxy)propyltrimethoxysilane and (3-aminopropyl)trimethoxysilane based on the reaction between epoxy and amine groups. The monomer was used to fabricate aerogels with excellent mechanical properties via sol–gel processes followed by supercritical CO2 drying. The influence of the sol–gel conditions on the chemical structure, morphology and mechanical property of the aerogels was investigated by NMR, TGA, SEM, nitrogen sorption analysis and DMA. BSQ aerogels prepared from the optimal sol–gel procedure showed excellent properties with high mechanical performance (compression modulus of 20.4 MPa) and low density (0.22 g cm−3), which are of great advantage for practical applications. Further, SiO2/BSQ composite aerogels with significantly improved mechanical performance than SiO2 aerogels can be obtained by co-condensing of BSQ monomer and tetraethoxysilane. The abundant hydroxyl groups in the BSQ precursor are believed to contribute to the robustness of BSQ and SiO2/BSQ composite aerogels due to the strengthened skeleton via the intermolecular H-bonds.
Co-reporter:Chun-yan Wang;Qian Yuan;Shu-guang Yang 杨曙光
Chinese Journal of Polymer Science 2015 Volume 33( Issue 4) pp:661-668
Publication Date(Web):2015 April
DOI:10.1007/s10118-015-1618-y
The asymmetric amphiphilic block copolymer polystyrene962-block-poly(ethylene oxide)227 (PS962-b-PEO227) canforms micelles with N, N-dimethylformamide (DMF) as co-solvent and water as selected solvent, and when the water content of the mixed solvent is higher than 4.5 wt%, the vesicle will be dominated. This work finds that once vesicles are formed in the DMF-water mixed solvent, the vesicle size and membrane thickness can be tuned by further increasing water content. As the water fraction elevated from 4.8 wt% to 13.0 wt%, the vesicle size dercreases from 246 nm to 150 nm, while the membrane thickness increases from 28 nm to 42 nm. In addition, the block copolymer packing and the free energy are analyzed as the vesicle size becomes small and the membrane becomes thick.
Co-reporter:Qi Liu;Longquan Shao;Haosen Fan;Yuhua Long;Ning Zhao
Journal of Materials Science 2015 Volume 50( Issue 11) pp:3976-3983
Publication Date(Web):2015 June
DOI:10.1007/s10853-015-8953-9
The composition and properties of silicone–hollow microsphere composites were studied in view of establishing a new type of maxillofacial prosthesis material. Two types of microspheres were used in different concentrations and were well dispersed in the silicone matrix. The mechanical properties of the composites were evaluated. Expancel hollow microspheres improve the density, Shore A hardness, and breaking elongation of the materials but degrade their tensile strength, tear strength, and dynamic mechanical properties, while opposite trends were observed with hollow SiO2 microspheres. Ideal properties for maxillofacial prosthetic applications can thereby be obtained by blending the two types of hollow microspheres in specific proportions.
Co-reporter:Zhijie Wang;Xinwei Xu;Jinghua Gong
Journal of Sol-Gel Science and Technology 2015 Volume 73( Issue 1) pp:154-160
Publication Date(Web):2015 January
DOI:10.1007/s10971-014-3506-2
Polyvinylpyrrolidone (PVPON)-boehmite hybrid thin film was deposited onto glass by sol–gel dip-coating method. The Fabry-Pérot fringe in visible spectra was applied to monitor the multilayer film thickness growth. Field-emission scanning electron microscope and Atomic force microscope were used to characterize the film’s microstructure. The film was composed of uniform boehmite nanoparticles about 20 nm. Addition of PVPON in the boehmite sol was effective in increasing the critical thickness of the films. When the as-deposited films were sintered at 500 °C, the boehmite was transformed to γ-alumina with the decreased film thickness.
Co-reporter:Ning Zhao;Zhen Wang;Chao Cai;Heng Shen;Feiyue Liang;Dong Wang;Chunyan Wang;Tang Zhu;Jing Guo;Yongxin Wang;Xiaofang Liu;Chunting Duan;Hao Wang;Yunzeng Mao;Xin Jia;Haixia Dong;Xiaoli Zhang
Advanced Materials 2014 Volume 26( Issue 41) pp:6994-7017
Publication Date(Web):
DOI:10.1002/adma.201401718
The surprising properties of biomaterials are the results of billions of years of evolution. Generally, biomaterials are assembled under mild conditions with very limited supply of constituents available for living organism, and their amazing properties largely result from the sophisticated hierarchical structures. Following the biomimetic principles to prepare manmade materials has drawn great research interests in materials science and engineering. In this review, we summarize the recent progress in fabricating bioinspired materials with the emphasis on mimicking the structure from one to three dimensions. Selected examples are described with a focus on the relationship between the structural characters and the corresponding functions. For one-dimensional materials, spider fibers, polar bear hair, multichannel plant roots and so on have been involved. Natural structure color and color shifting surfaces, and the antifouling, antireflective coatings of biomaterials are chosen as the typical examples of the two-dimensional biomimicking. The outstanding protection performance, and the stimuli responsive and self-healing functions of biomaterials based on the sophisticated hierarchical bulk structures are the emphases of the three-dimensional mimicking. Finally, a summary and outlook are given.
Co-reporter:Hao Wang, Junjie Wu, Chao Cai, Jing Guo, Haosen Fan, Caizhen Zhu, Haixia Dong, Ning Zhao, and Jian Xu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 8) pp:5602
Publication Date(Web):March 31, 2014
DOI:10.1021/am406052u
Inspired by the remarkable adhesion of mussel, dopamine, a mimicking adhesive molecule, has been widely used for surface modification of various materials ranging from organic to inorganic. However, dopamine and its derivatives are expensive which impede their application in large scale. Herein, we replaced dopamine with low-cost catechol and polyamine (only 8% of the cost of dopamine), which could be polymerized in an alkaline solution and deposited on the surfaces of various materials. By using this cheap and simple modification method, polypropylene (PP) separator could be transformed from hydrophobic to hydrophilic, while the pore structure and mechanical property of the separator remained intact. The uptake of electrolyte increased from 80% to 270% after the hydrophilic modification. Electrochemical studies demonstrated that battery with the modified PP separator had a better Coulombic efficiency (80.9% to 85.3%) during the first cycle at a current density of 0.1 C, while the discharging current density increased to 15 C and the discharge capacity increased by 1.4 times compared to the battery using the bare PP separator. Additionally, the modification allowed excellent stability during manifold cycles. This study provides new insights into utilizing low-cost chemicals to mimic the mussel adhesion and has potential practical application in many fields.Keywords: bioinspired; catechol; Li-ion battery; mussel; polyamine; separator;
Co-reporter:Haosen Fan, Hao Wang, Jing Guo, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2014 Volume 414() pp:46-49
Publication Date(Web):15 January 2014
DOI:10.1016/j.jcis.2013.09.042
•2D leaf-like PANI was prepared using SDBS as dopant.•SDBS plays a dual role in serving as soft template and improving hydrophobic property.•Good hydrophobicity is mainly due to the hydrophobic long dodecyl groups of SDBS dopant.Leaf-like hierarchical polyaniline (PANI) structure with interlaced nanofibers on the surface was prepared by chemical oxidation polymerization of aniline assisted by sodium dodecyl benzene sulfonate (SDBS). The chemical structure and the composition of the leaf-like PANI obtained were characterized by FTIR, UV–vis, XRD and XPS. In order to investigate the formation mechanism of such micro/nanostructures, some micro/nanostructures of PANI polymerized at different polymerization times were synthesized and observed for comparison. The results show that the PANI micro/nanostructures originate from PANI microleaves due to SDBS as soft template, which then covered with interlaced nanofibers on the surface. The leaf-like PANI micro/nanostructures exhibit good hydrophobic property with a water contact angle of 134.3° resulted from the hydrophobic long dodecyl groups of SDBS dopant.
Co-reporter:Zhijie Wang, Jinghua Gong, Jinghong Ma and Jian Xu
RSC Advances 2014 vol. 4(Issue 28) pp:14708-14714
Publication Date(Web):13 Mar 2014
DOI:10.1039/C4RA00160E
A super-hydrophobic 2024 aluminum alloy surface with multi-scale hierarchical flower-like boehmite (γ-AlOOH) structure has been fabricated via a facile hydrothermal approach. The different morphologies of the γ-AlOOH films were totally controlled by the preparation conditions for crystal growth, such as reaction solution and time. The morphology and structure of the films were characterized using scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The super-hydrophobicity can be attributed to both the rough multi-scale structural boehmite coating and surface enrichment of low surface energy with the chemical vapor deposition of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (POTS). The resulting super-hydrophobic surface exhibits a water contact angle of 155° and a sliding angle of about 5°. The corrosion behavior was investigated with potentiodynamic polarization measurements and it was found that the super-hydrophobic coating considerably improved the corrosion resistant performance of aluminum alloy.
Co-reporter:Xiaofeng Li, Liang Zhang, Xinglin Guo, Caizhen Zhu, Zhong-Zhen Yu, Ning Zhao and Jian Xu
RSC Advances 2014 vol. 4(Issue 91) pp:49861-49865
Publication Date(Web):17 Sep 2014
DOI:10.1039/C4RA06155A
Band-like folds with high aspect ratio and birefringence behavior were observed on an in situ formed thin poly(vinyl alcohol) (PVA) hydrogel film via freezing–thawing treatment of PVA aqueous solution coated on glass. The crystallites generated during the freezing of the PVA solution cross-linked the PVA to form the hydrogel film. The volume expansion of the hydrogel film due to the absorption of condensed water in thawing induced the formation of folds. These folds show interesting birefringence behavior. The morphology, crystallization and birefringence behavior of the folds were characterized by polarized optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. A plausible principle for the fold formation is also discussed. It has been found that the moderate interaction between the hydrogel film and the substrate and the existence of condensed water on the frozen hydrogel film play important roles in the appearance of the folds.
Co-reporter:Zhijie Wang, Yu Tian, Haosen Fan, Jinghua Gong, Shuguang Yang, Jinghong Ma and Jian Xu
New Journal of Chemistry 2014 vol. 38(Issue 3) pp:1321-1327
Publication Date(Web):21 Jan 2014
DOI:10.1039/C3NJ01323E
A new approach for the fabrication of γ-AlOOH nanoflake films has been developed. The nanoflakes were successfully formed on a glass substrate via a simple, low temperature, and seed-assisted hydrothermal technique. A large amount of γ-AlOOH nanoflakes with various thicknesses interlaced together, resulting in a nest-like layer of film with their sharp edges preferentially vertical to glass substrates. The effects of hydrothermal temperature, time and concentration on the morphology and phase of the γ-AlOOH nanoflake films are investigated. X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman microscopy were used to characterize the structures and morphologies of the films. The growth mechanism of the γ-AlOOH nanoflake films was also discussed. Moreover, the nanostructural films of γ-AlOOH showed a transition from hydrophilic to super-hydrophobic with the chemical vapor deposition of PFOS.
Co-reporter:Liang Zhang;Haizhu Yu;Ning Zhao;Zhi-Min Dang
Journal of Applied Polymer Science 2014 Volume 131( Issue 22) pp:
Publication Date(Web):
DOI:10.1002/app.41057
ABSTRACT
Patterned polymer surfaces with contrasting wettability are prepared by polydopamine (PD) modification. The fabrication process involves spraying dopamine solution droplets on hydrophobic polymer surfaces and PD deposition derived from the oxidative polymerization of dopamine. Each dopamine solution droplets functions as microreactor leading to the formation of patterned PD thin films on the solid/liquid interfaces. Multiple kinds of polymer substrates, including polypropylene, polystyrene, polycarbonate, polyethylene and polytetrafluoroethylene, are endowed with PD patterns using this method. Two types of wetting behaviors are achieved in relation to the micro morphology of the substrates. If smooth or porous substrates are used, the as-formed film exhibited hydrophilic-hydrophobic pattern. When a hierarchical-structured film is used, the uncoated and coated regions have similar static wettability but different dynamic wetting behavior. This PD modification method is also proved to be suitable for flexible and curved surfaces. The results along with the fact that PD could deposit on virtually any surfaces makes this method find wide practical applications in many fields. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41057.
Co-reporter:Zhijie Wang, Hong Du, Jinghua Gong, Shuguang Yang, Jinghong Ma, Jian Xu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 450() pp: 76-82
Publication Date(Web):
DOI:10.1016/j.colsurfa.2014.03.014
Co-reporter:Zhijie Wang;Weiwei Ji;Hong Du;Xiangyu Li
Journal of Sol-Gel Science and Technology 2014 Volume 72( Issue 3) pp:511-517
Publication Date(Web):2014 December
DOI:10.1007/s10971-014-3466-6
Nanosheet AlOOH and silica spheres composite thin film was deposited onto glass by sol–gel dip-coating method through hydrolysis of boiling water immersion. A silica sol and an alumina sol are employed in dipping process for the preparation of hierarchical nanostructures thin film. The morphology and structure of the films were characterized using field emission scanning electron microscopy and X-ray diffraction. The super-hydrophobicity with high adhesion forces can be attributed to both the rough multi-scale structural coating and surface enrichment of low surface energy with the chemical vapor deposition of 1H,1H,2H,2H-perfluorodecyltriethoxysilane.
Co-reporter:Xiaoli Yang, Ning Zhao, Qingzhu Zhou, Chao Cai, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2013 vol. 1(Issue 20) pp:3359-3366
Publication Date(Web):26 Mar 2013
DOI:10.1039/C3TC30324A
This paper describes a straightforward method to precisely prepare monodisperse ZrO2@SiO2 core–shell nanoparticles (CSNs) by sol–gel polymerization of TEOS in the presence of ZrO2 cores without additional capping agents. We studied the morphology and composition of CSNs by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). It has been found that the citric acid groups adsorbed onto the ZrO2 surface during the preparation of ZrO2 as well as the slow hydrolysis and condensation of TEOS in isopropanol are crucial for the selective growth of silica on the surface of ZrO2 cores. The thickness of the silica shell can be facilely controlled from about 4 to 30 nm by varying the concentration of TEOS, with the refractive indices of the prepared CSNs tuned accordingly from about 1.2 to 1.9. The coated silica shell, which can be well dispersed in solvents such as methanol and ethanol, can improve the dispersibility of pure ZrO2 nanoparticles which can only be dispersed in water. Moreover, the formation of the silica shell improved the chemical reactivity of pure ZrO2 nanoparticles. After modifying with methyltriethoxysilane (MTES), the CSNs can be well dispersed in various organic solvents, such as dimethylbenzene, chloroform and isoamyl alcohol, which may find applications in optically transparent resins with controllable refractive index or organic silicon packaging materials with high refractive index for LED and so on. Additionally, other silane coupling agents can also be applied to modify the surface chemical properties of CSNs, which may provide more potential applications.
Co-reporter:Fangfang Si, Ning Zhao, Li Chen, Jian Xu, Qingsheng Tao, Jinyong Li, Chunbo Ran
Journal of Colloid and Interface Science 2013 Volume 407() pp:482-487
Publication Date(Web):1 October 2013
DOI:10.1016/j.jcis.2013.06.068
•Hybrid molecule STA-APTES was obtained by the reaction between STA and APTES.•A superhydrophobic coating can be obtained by casting the STA-APTES solution.•The coating can be cross-linked by the APTES moieties under alkaline atmosphere.•The cross-linked STA-APTES coating shows enhanced thermal and solvent resistance.The chemical originals of natural superhydrophobic surfaces are based on botanic or animal wax or fat, which have poor chemical and thermal resistance. Herein, we report a simple chemical modification of stearic acid (STA) with γ-aminopropyl triethoxysilane (APTES), to obtain an organic–inorganic molecular hybrid STA-APTES compound. A flower-like hierarchically structured surface with superhydrophobicity can be obtained simply by casting the STA-APTES solution under ambient circumstance. The crystallization of the hydrocarbon chain from STA leads to the formation of the binary microstructure and reduces the surface tension, contributing to the superhydrophobicity of the as-formed surface. In addition, the condensation of Si(OCH2CH3)3 from APTES can lead to the cross-linking of the resultant surface, which endows the as-formed superhydrophobic surface with high performances, such as excellent thermal and solvent resistance, etc. This superhydrophobic surface prepared is superior to its many analogs in nature, promising a wide application especially in harsh circumstance.Graphical abstract
Co-reporter:Haosen Fan, Hao Wang, Jing Guo, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2013 Volume 409() pp:255-258
Publication Date(Web):1 November 2013
DOI:10.1016/j.jcis.2013.07.056
•Star-shaped and leaf-shaped PANIs were prepared using lithium triflate as dopant.•Star-shaped and leaf-shaped PANIs both exhibit good superhydrophobicity.•The good superhydrophobicity is due to the special nanoweb structure and low surface tension of dopant.Star-shaped and leaf-shaped polyaniline (PANI) hierarchical structures with interlaced nanofibers on the surface were successfully prepared by chemical polymerization of aniline in the presence of lithium triflate (LT). Chemical structure and composition of the star-like PANI obtained were characterized by FTIR and UV–vis spectra. PANI 2D architectures can be tailored from star-shaped to leaf-shaped structures by change the concentration of LT. The synthesized star-like and leaf-like polyaniline show good superhydrophobicity with water contact angles of both above 150° due to the combination of the rough nanoweb structure and the low surface tension of fluorinated chain of dopant. This method is a facile and applicable strategy for a large-scale fabrication of 2D PANI micro/nanostructures. Many potential applications such as self-cleaning and antifouling coating can be expected based on the superhydrophobic PANI micro/nanostructures.
Co-reporter:Xiaoyan Zhang, Wangyang Fu, Chunting Duan, Hong Xiao, Meiwu Shi, Ning Zhao, Jian Xu
Applied Surface Science 2013 Volume 266() pp:225-229
Publication Date(Web):1 February 2013
DOI:10.1016/j.apsusc.2012.11.153
Abstract
Superhydrophobicity is commonly regarded as a surface property that has important consequences for self-cleaning applications. Here we show interestingly that the superhydrophobicity is closely connected to the bulk buoyancy performance of kapok fiber aggregates, a natural material endowed with superhydrophobicity and extraordinary high porosity. First of all, we have determined the superhydrophobicity of a single kapok fiber, which can be ascribed to its micro-nano-binary structure (MNBS) and the thin hydrophobic paraffinic wax layer covered on the surface. Second, based on classic capillary and wicking theory, the buoyancy performance of the kapok fiber aggregates can be modeled and we demonstrate that their buoyancy performance is actually determined by the superhydrophobicity of individual kapok fibers. Our results also suggest an optimized density ∼0.015 g cm−3 for using kapok fiber aggregates as the lightest natural buoyancy.
Co-reporter:Haosen Fan, Ning Zhao, Hao Wang, Xiaofeng Li, Jian Xu
Materials Letters 2013 Volume 92() pp:157-160
Publication Date(Web):1 February 2013
DOI:10.1016/j.matlet.2012.10.048
Carpenterworm-like multidimensional architectures of polyaniline/multi-walled carbon nanotubes (PANI–MWNTs), with a diameter of about 2.5 μm and consisting of many interlaced PANI nanorods on the surface of MWNTs, were successfully synthesized in a mixture of ethanol and water. Chemical structure and composition of the prepared PANI–MWNTs nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, ultraviolet and visible spectroscopy (UV–vis), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It has been found that the concentration of ethanol in the solution plays a critical role in controlling the morphology of the resultant nanocomposites. The obtained carpenterworm-like PANI–MWNTs nanocomposites exhibit enhanced electrochemical behavior in comparison with MWNTs and PANI, indicating a potential application in electrode material of supercapacitors or secondary batteries.Highlights► Carpenterworm-like PANI–MWNTs nanocomposites are prepared using a mixture of ethanol and H2O. ► PANI–MWNTs nanocomposites with different morphology are obtained by tuning the composition of the solvent. ► Carpenterworm-like PANI–MWNTs nanocomposites exhibits enhanced electrochemical behavior.
Co-reporter:Haosen Fan, Ning Zhao, Hao Wang, Xiaofeng Li, Jian Xu
Materials Letters 2013 Volume 92() pp:115-118
Publication Date(Web):1 February 2013
DOI:10.1016/j.matlet.2012.10.081
A novel multidimensional architecture of tremella-like polyaniline (PANI) has been synthesized in the presence of oxalic acid (OA) by a template-free method. The PANI tremella is about 3–5 μm in average diameter and consist of petals of interlaced sheets with a thickness of about 20 nm. Chemical structures of obtained PANI were characterized by Fourier transform infrared spectroscopy (FTIR) and Ultraviolet and visible spectroscopy (UV–vis). It is found the micro-nanostructured PANI exhibits good electrochemical behavior in 0.1 M HCl electrolyte solution, indicating a potential application in sensors or electrochemical devices. In addition, the effect of OA concentration on the morphology of the tremella-like PANI was also investigated.Highlights► Tremella-like PANI was prepared in the presence of oxalic acid by a template-free method. ► Tremella-like PANI exhibits good electrochemical behavior. ► The obtained tremella-like PANI shows potential application in sensors or electrochemical devices.
Co-reporter:Songmei Ma, Xiaocun Qi, Yugai Cao, Shuguang Yang, Jian Xu
Polymer 2013 Volume 54(Issue 20) pp:5382-5390
Publication Date(Web):6 September 2013
DOI:10.1016/j.polymer.2013.07.047
The hydrogen bonded polymer complex bulk and thin film was prepared by solution mixing and layer-by-layer assembly, respectively. Poly(vinylpyrrolidone) (PVPON) and poly(ethylene oxide) (PEO) were hydrogen bonding acceptor polymers while poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) were hydrogen bonding donor polymers. The detachment of hydrogen bond between the chains in polymer complexes was investigated during the dissolution in alkaline solution, ionic liquid and tertiary amine N-oxide. We compared the dissolution process of the polymer complex bulk with the polymer complex thin film, and discussed the polymer chain length, chain entanglement degree and temperature effect on hydrogen bond detachment and dissolution of polymer complexes.
Co-reporter:Hai-fan Xiang;Dong Wang;Hui-chao Liua;Ning Zhao 赵宁
Chinese Journal of Polymer Science 2013 Volume 31( Issue 3) pp:521-529
Publication Date(Web):2013 March
DOI:10.1007/s10118-013-1241-8
Sound absorption properties of natural kapok fibers have been investigated. Kapok fibrous assemblies with different bulk density, thickness, fiber length and orientation were manufactured, and their acoustical performances were evaluated by using an impedance tube instrument. Results show that the kapok fiber has excellent acoustical damping performance due to its natural hollow structure, and the sound absorption coefficients of kapok fibrous assemblies are significantly affected by the bulk density, thickness and arrangement of kapok fibers but less dependent on the fiber length. Compared with assemblies of commercial glass wool and degreasing cotton fibers, the kapok fiber assemblies with the same thickness but much smaller bulk density may have the similar sound absorption coefficients. Theoretical modelling of the acoustical damping performance of kapok fibers shows a good agreement with the experimental data. All the results demonstrate that kapok fiber is a promising light and environment-friendly sound absorption material.
Co-reporter:Xiao-fang Liu;Shuai-xia Tan;Xiao-li Zhang
Chinese Journal of Polymer Science 2013 Volume 31( Issue 7) pp:1022-1028
Publication Date(Web):2013 July
DOI:10.1007/s10118-013-1294-8
A full-field finite element method (FEM) analysis combined with electronic speckle pattern interferometry (ESPI) measurement was developed to investigate defect evolution in polymer films. Different from the previous reports, which only compare the ESPI experimental and FEM simulated results at several points or lines, herein the full-field FEM results were exported, subtracted with a continuous distribution. By choosing proper parameters and number of substeps, the simulated and experimental results showed excellent correspondence. Furthermore, the displacement fields vertical to the tensional direction were also presented, and the strain field was preliminarily evaluated. The current method of combination of ESPI and FEM allows for capturing the experimental fringe maps to validate and optimize FEM results simulated, and would give a higher security to structural and mechanical analysis of polymeric materials.
Co-reporter:Cai-zhen Zhu;Xiao-lan Yu;Xiao-fang Liu;Yun-zen Mao
Chinese Journal of Polymer Science 2013 Volume 31( Issue 5) pp:823-832
Publication Date(Web):2013 May
DOI:10.1007/s10118-013-1272-1
Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction (2D SAXS/WAXD). The SAXS results show that during pre-oxidation between 180 °C and 275 °C, the volume content of microvoids increases with the temperature increasing, which may be one of reasons for the decrease of tensile strength of pre-oxidized fibers. 253 °C was the critical transition temperature, the length, diameter, aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature. After the high temperature carbonization, lots of spindly microvoids formed. WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 °C and then decreased with the increase of temperature during the pre-oxidation. The diffraction peak of PAN fibers at 2θ ≈ 17° almost disappeared at the end of preoxidation while the diffraction peak of aromatic structure at 2θ ≈ 25° appeared at 253 °C. During carbonization, the peak intensity at 2θ ≈ 25° increased apparently due to the formation of graphite structure. The results obtained give a deep understanding of the microstructure development in the PAN fibers during pre-oxidation and carbonization, which is important for the preparation of high performance carbon fibers.
Co-reporter:Pengchao Liu, Yizheng Zhu, Jinghong Ma, Shuguang Yang, Jinghua Gong, Jian Xu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2013 Volume 436() pp:489-494
Publication Date(Web):5 September 2013
DOI:10.1016/j.colsurfa.2013.07.023
•Aluminum nitrate and polyacrylonitrile form spinning solution in DMF.•Transparent spinning solution is stable.•The alumina nanofibers possess porous surfaces and hollow cross sections.•The “Kirkendall effect” mechanism is proposed to explain the formation process.Porous alumina nanofibers with hollow structure were fabricated by single capillary electrospinning of aluminum nitrate (Al(NO3)3)/polyacrylonitrile (PAN) precursor solution, followed by sintering treatment. The Al(NO3)3/PAN composite nanofibers and sintered nanofibers were characterized by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). It is found that the obtained alumina nanofibers show porous external surfaces and hollow sections. Upon sintering the composite nanofibers at 1300 °C, the nanofibers are consisted of α-phased crystalline grains. Sintering temperature plays an important role in controlling the morphology and crystal structure of the nanofibers. A mechanism based on “Kirkendall effect” was proposed to explain the formation process of the hollow structure.Porous alumina nanofibers with hollow structure were fabricated by single-spinneret electrospinning of aluminum nitrate (Al(NO3)3)/polyacrylonitrile (PAN) precursor solution, followed by sintering treatment. A mechanism based on “Kirkendall effect” was proposed to explain the formation process of the hollow structure.
Co-reporter:Liang Zhang ; Junjie Wu ; Yongxin Wang ; Yuhua Long ; Ning Zhao
Journal of the American Chemical Society 2012 Volume 134(Issue 24) pp:9879-9881
Publication Date(Web):June 2, 2012
DOI:10.1021/ja303037j
We combine two amazing abilities found in nature: the superhydrophobic property of lotus leaf and the adhesive ability of mussel adhesive protein. The molecular structure mimic of the single units of adhesive proteins, dopamine, was polymerized in an alkaline aqueous solution to encapsulate microparticles. The as-formed thin polydopamine walls worked as reactive templates to generate silver nanoparticles on the capsuled particles. As a result, core/shell/satellite composite particles were generated with a hierarchical structure similar to the micromorphology of lotus leaf. The composite particles exhibited extremely water repellence after fluorination. Because dopamine can deposit and adhere to all kinds of materials, this method can be applied to diverse microparticles, from organic to inorganic. In addition, particles of different sizes and matters can be modified to superhydrophobic particles in one pot. Magnetic particles have also been prepared which could be used as oil-absorbent and magnetic controlled carriers. “Oil marbles” formed underwater were achieved for the first time.
Co-reporter:Haosen Fan, Hao Wang, Ning Zhao, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2012 vol. 22(Issue 6) pp:2774-2780
Publication Date(Web):15 Dec 2011
DOI:10.1039/C1JM14311E
A facile method was successfully developed for the preparation of a hierarchical nanocomposite of vertical polyaniline (PANI) nanorods aligned on the surface of functional multiwalled carbon nanotubes (FMWNTs) by in situ polymerization of PANI on the surface of FMWNTs. The formation mechanism was illustrated according to the morphological evolution of PANI-FMWNTs nanocomposite at different polymerization times. The hierarchical nanocomposite possessed higher special capacitance and better stability than each individual component as supercapacitor electrode materials due to the synergistic effect of both components, as well as to the special hierarchical structure, which not only increases the specific surface area of the nanocomposite but also facilitates the penetration of electrolyte ions. This research gives a better insight into the preparation of functional hybrid nanocomposites by combining different dimensional nanomaterials.
Co-reporter:Xiaoli Yang, Ning Zhao, Qingzhu Zhou, Zhen Wang, Chunting Duan, Chao Cai, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:18010-18017
Publication Date(Web):10 Jul 2012
DOI:10.1039/C2JM33220E
A facile method was developed to fabricate hollow amino-functionalized organosilica microspheres based on the hydrolysis and condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) in an aqueous system without an additional template and catalyst. The hollow hybrid organosilica microspheres obtained have been characterized by scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption measurements. The results of Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis displayed the composition of the synthesized hollow microspheres and the presence of amino groups on the surface. A self-templated and self-catalyzed mechanism for the formation of the hollow microspheres is proposed: the protonated APTES acts as both a catalyst for the reaction and a stabilizer for the hydrophobic precursor droplets, while the droplets themselves act as soft templates, and the consumption of the precursors leads to the formation of a hollow structure. The morphology and the size distribution of the organosilica microspheres can be controlled by tuning the composition of the precursors, and the stirring speed, as well as the reaction temperature. The large cavity with an open hole on the shell and the reactive amino groups on the surface of the hybrid organosilica microspheres promise many potential applications. Examples of employing the microspheres as adsorbents and phase change microcapsules have been presented.
Co-reporter:Caizhen Zhu, Xiaofang Liu, Xiaolan Yu, Ning Zhao, Jianhong Liu, Jian Xu
Carbon 2012 Volume 50(Issue 1) pp:235-243
Publication Date(Web):January 2012
DOI:10.1016/j.carbon.2011.08.040
Small angle X-ray scattering and molecular dynamics simulation were used to study the microvoid evolution in carbon fibers (CFs) during tensile deformation. The stress–strain relation and the parameters of microvoids, such as the length, diameter, orientation angle and relative volume were measured. The results demonstrated that during the tensile deformation of CFs, (1) the microvoid volume increased gradually; (2) the microvoid orientation angle with respect to the fiber axis decreased; (3) the mean microvoid length statistically decreased; (4) the short range structure did not change while the bond length of partial C–C increased and the medium and long range structure became disordered; (5) the angle of partial C–C–C shifted to the small angle; (6) the increase of bond lengths and decrease of bond angles mainly appeared at stress concentration areas which were the key damage points. It was indicated that reasonable control of small microvoid growth and stress release could improve the performance of CFs.
Co-reporter:Haosen Fan, Ning Zhao, Hao Wang, Yuhua Long, Xiaofeng Li and Jian Xu
RSC Advances 2012 vol. 2(Issue 31) pp:11887-11891
Publication Date(Web):08 Oct 2012
DOI:10.1039/C2RA21723F
Highly uniform core–shell structured polyaniline–multiwall carbon nanotube nanocomposites have been successfully prepared by noncovalent coating of a polyaniline shell on the wall of MWNTs with the assistance of 1-pyrenesulfonic acid. It is found that 1-pyrenesulfonic acid plays important roles in dispersing MWNTs and directing the polymerization of the polyaniline shell by the sulfonic groups. The obtained nanocomposites exhibit a higher specific capacitance. This research provides a new approach for designing core–shell hybrid materials with potential application in high-performance electrochemical supercapacitors.
Co-reporter:Haosen Fan, Ning Zhao, Hao Wang, Xiaofeng Li, Jian Xu
Materials Letters 2012 Volume 78() pp:42-45
Publication Date(Web):1 July 2012
DOI:10.1016/j.matlet.2012.03.053
Polyaniline with a leaf-like hierarchical structure of 3 μm in length, 2 μm in width, 100 nm in thickness and crisscrossed nanofibers decorated on the surface, was successfully prepared in one step polymerization of aniline in the presence of sodium heptafluorobutyrate. The synthesized polyaniline shows superhydrophobicity with a water contact angle of 151° due to the combination of the low surface tension of fluorinated chain and the rough micro/nanostructure. Chemical structure and composition of the resultant PANI were characterized by FTIR, UV–vis, XRD and XPS. The formation mechanism of the hierarchical structure was investigated by monitoring the morphology development with the polymerization time. This method is facile and applicable for the large scale fabrication. Many potential applications can be expected based on the superhydrophobic PANI micro/nanostructures.Highlights► Leaf-like PANI was prepared by using sodium heptafluorobutyrate. ► Leaf-like PANI exhibits good superhydrophobic property. ► The good superhydrophobicity of PANI is due to its hierarchical structure and the low surface tension.
Co-reporter:Haosen Fan, Hao Wang, Xiaolan Yu, Ning Zhao, Xiaoli Zhang, Jian Xu
Materials Letters 2012 Volume 71() pp:70-73
Publication Date(Web):15 March 2012
DOI:10.1016/j.matlet.2011.11.121
Different polyaniline (PANI) micro/nanostructures, such as hollow microdisks, nanospheres, and nanofibers, have been synthesized in the presence of polyvinylpyrrolidone (PVP) by changing the pH values of reaction system through chemical oxidation polymerization. The formation mechanism experiments indicated that the disk-shaped PANI originated from cycloidal nanoplates, which then self-assembled into disk-shaped PANI. And pH value has an important effect on the arranged state of PVP chains and further impacts the micro/nanostructures of obtained products. It is found that the obtained PANI micro/nanostructures exhibit better electrochemical behavior in HCl solution with the decrease of pH value of reaction system, indicating a potential application in biosensor.Highlights► Different PANI micro/nanostructures were synthesized by changing the pH values of reaction system. ► PANI micro/nanostructures exhibit good electrochemical behavior. ► PVP and pH values play significant roles in formation of PANI micro/nanostructures.
Co-reporter:Junjie Wu;Ning Zhao;Xiaoli Zhang
Cellulose 2012 Volume 19( Issue 4) pp:1239-1249
Publication Date(Web):2012 August
DOI:10.1007/s10570-012-9731-3
Cellulose/silver nanoparticles (Ag NPs) composites were prepared and their catalytic performance was evaluated. Porous cellulose microspheres, fabricated from NaOH/thiourea aqueous solution by a sol–gel transition processing, were served as supports for Ag NPs synthesis by an eco-friendly hydrothermal method. The regenerated cellulose microspheres were designed as reducing reagent for hydrothermal reduction and also micro-reactors for controlling growth of Ag NPs. The structure and properties of obtained composite microspheres were characterized by Optical microscopy, UV–visible spectroscopy, WXRD, SEM, TEM and TG. The results indicated that Ag NPs were integrated successfully and dispersed uniformly in the cellulose matrix. Their size (8.3–18.6 nm), size distribution (3.4–7.7 nm), and content (1.1–4.9 wt%) were tunable by tailoring of the initial concentration of AgNO3. Moreover, the shape, integrity and thermal stability were firmly preserved for the obtained composite microspheres. The catalytic performance of the as-prepared cellulose/Ag composite microspheres was examined through a model reaction of 4-nitrophenol reduction in the presence of NaBH4. The composites microspheres exhibited good catalytic activity, which is much high than that of hydrogel/Ag NPs composites and comparable with polymer core–shell particles loading Ag NPs.
Co-reporter:Yongxin Wang, Xiaofang Liu, Xiaofeng Li, Junjie Wu, Yuhua Long, Ning Zhao, and Jian Xu
Langmuir 2012 Volume 28(Issue 31) pp:11276-11280
Publication Date(Web):July 24, 2012
DOI:10.1021/la301972r
The spreading of a miscible liquid with a low surface tension on a water surface generates the directional motion of submerged polymer hydrogels, which could be attributed to convective flows resulting from the gradient of surface tension along the surface (Marangoni effect). The direction and velocity of this motion can be well controlled by altering the driving conditions. Furthermore, a spherical hydrogel can smartly find the path to walk through a microfluidic maze when liquid mixing occurs near the maze exit. This convenient chemical driving approach to transporting submerged objects in a desired way may be useful in microfluidics, micromechanics, and other applications.
Co-reporter:Xiaofeng Li, Liang Zhang, Yongxin Wang, Xiaoli Yang, Ning Zhao, Xiaoli Zhang, and Jian Xu
Journal of the American Chemical Society 2011 Volume 133(Issue 11) pp:3736-3739
Publication Date(Web):February 24, 2011
DOI:10.1021/ja1106767
Patterned “bead in pore” composite film with hemispherical or mushroomlike TiO2 microparticles lying in the holes of a honeycomblike polystyrene matrix has been fabricated by a template-free bottom-up approach from a homogeneous solution of TiCl4/polystyrene/CHCl3 using the breath figures method. It is a very simple way to prepare hemispherical or mushroomlike TiO2 microparticles and to get the hexagonally nonclose-packed arrays of asymmetrical particles with or without polymer matrix, which have potential applications in photonics.
Co-reporter:Yuhua Long, Junjie Wu, Hao Wang, Xiaoli Zhang, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2011 vol. 21(Issue 13) pp:4875-4881
Publication Date(Web):18 Feb 2011
DOI:10.1039/C0JM03838E
Here we demonstrate a new route to achieve the sintering of silver nanoparticles (Ag NPs) at room temperature. The as-prepared Ag NPs coalesced when they were immersed in electrolyte solutions, such as NaCl and MgSO4. The square resistances of Ag NPs thin films decreased from tens of kiloohms to lower than 1 ohm after treatment with electrolyte solutions for 10 s. Conductive Ag NPs thin films can be created on various substrates coated by polydopamine, a mussel-inspired polymer, viasilver-plating followed by treatment with electrolyte solutions at room temperature.
Co-reporter:Qingzhu Zhou, Haifan Xiang, Haosen Fan, Xiaoli Yang, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2011 vol. 21(Issue 34) pp:13056-13061
Publication Date(Web):01 Aug 2011
DOI:10.1039/C1JM11149C
A simple procedure was developed to fabricate uniform-sized hollow organic-inorganic silica spheres with a golf ball-like wrinkled surface. Two precursors, methyltrimethoxylsilane and tetraethoxysilane were hydrolyzed in solution of ammonia, and the hollow morphology was obtained by co-condensation of the two precursors, followed by self-assembly of silica and polymeric organoalkoxysilane. The composition of the two precursors and temperature were of importance for the morphological characteristics of organic-inorganic silica spheres. In addition, their size and distribution can be controlled by the dispersion manner of precursors into aqueous solution of ammonia. The framework components indicated the presence of silica and polymethylsilsesquioxane, and polymethylsilsesquioxane was distributed on the surface of the microspheres. Self-assembly of silica and polymethylsilsesquioxane based on Ostwald ripening process was proposed to explain the formation of hollow structures and golf ball-like wrinkled surface.
Co-reporter:Liang Zhang, Ning Zhao, Xiaofeng Li, Yuhua Long, Xiaoli Zhang and Jian Xu
Soft Matter 2011 vol. 7(Issue 8) pp:4050-4054
Publication Date(Web):03 Mar 2011
DOI:10.1039/C0SM01084G
Superhydrophobic surfaces, which have amazing abilities such as self-cleaning and drag reduction, have aroused great interest in both academic studies and industrial fields in the past decade. Although many methods and techniques to fabricate superhydrophobic surfaces have been investigated, most of the coatings have a lack of adherence which hinders the practical usage. Herein, we introduce a superhydrophobic coating developed from ethyl α-cyanoacrylate (ECA), which is a kind of widely used glue with tenacious adhesion to various substrates. A liquid film of ECA monomers was coated on a substrate and put in an environment of ammonia vapor and high humidity at room temperature. The polymerization concurrently started at the top of the film triggered by ammonia and at the bottom initiated by the substrate. A layer of PECA microfibers was formed at the surface first, and then vapor phase polymerization of the volatilized ECA monomers was conducted on the as-formed microfibers generating twisted and coiled micro/nanofibers. After the monomers were all consumed, a PECA coating with three layers were generated: one layer of micro/nanofibers on top, one layer of microfibers in the middle and one layer of bulk PECA at the bottom. The polymeric coating obtained a CA as high as 158° and SA of 4° due to the micro/nanofiber-structured surface and a good adhesion to the substrate.
Co-reporter:Haifan Xiang, Yuhua Long, Xiaolan Yu, Xiaoli Zhang, Ning Zhao and Jian Xu
CrystEngComm 2011 vol. 13(Issue 15) pp:4856-4860
Publication Date(Web):14 Mar 2011
DOI:10.1039/C0CE00980F
Here, we have introduced a novel and facile method to prepare porous hollow CuO nanofibers and Cu nanofibers via single-spinneret electrospinning of polyvinyl pyrrolidone (PVP)/copper acetate (Cu(CH3COO)2) solution followed by annealing and reduction. In this approach, the diameter and the shell thickness of the fibers can be simply adjusted by the concentration of PVP and the ratio of PVP to Cu(CH3COO)2. A possible mechanism is proposed to explain the formation of porous hollow CuO and Cu nanofiber. This method provides an new idea to prepare metal-oxide and metal fibers with a long continuous porous hollow morphology.
Co-reporter:Haifan Xiang, Liang Zhang, Zhen Wang, Xiaolan Yu, Yuhua Long, Xiaoli Zhang, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2011 Volume 359(Issue 1) pp:296-303
Publication Date(Web):1 July 2011
DOI:10.1016/j.jcis.2011.03.076
Multifunctional superhydrophobic polymethylsilsesquioxane (PMSQ) surfaces with excellent solvent resistance, thermal stability and enhanced sound absorption property were manufactured by electrospinning. The surfaces with various hierarchical morphologies and hydrophobicity were obtained by electrospinning at the different stages of sol–gel transition of PMSQ prepolymer solution. At the stage with a proper viscosity the superhydrophobic PMSQ surface with a contact angle as high as 151° and a sliding angle as low as 8° was prepared. Due to the excellent thermal stability and solvent resistance properties of the cured PMSQ, the resultant surfaces remain superhydrophobicity after thermal treatment at 300 °C and immersion into many solvents. Additionally, an enhanced acoustical performance and ultra water repellency were obtained simultaneously when the traditional acoustical sponge was decorated with the electrospun PMSQ superhydrophobic surface. The robust superhydrophobic PMSQ surfaces may promise practical applications in many fields.Graphical abstractSuperhydrophobic PMSQ surfaces with excellent solvent resistance and thermal stability were prepared. Modifying sponge with PMSQ not only endows ultra water repellency, but also enhances acoustic performance by 12%.Highlights► Superhydrophobic PMSQ surfaces were prepared by electrospinning at sol–gel transition. ► Superhydrophobic PMSQ surfaces show excellent resistance to solvents. ► Superhydrophobic PMSQ surfaces show thermal stability as high as 300 °C. ► Superior acoustical performance was obtained when the sponge decorated with PMSQ.
Co-reporter:Jinghong Ma, Shuguang Yang, Yuefang Li, Xun Xu and Jian Xu
Soft Matter 2011 vol. 7(Issue 19) pp:9435-9443
Publication Date(Web):26 Aug 2011
DOI:10.1039/C1SM05587A
Hydrogen-bonded films were prepared by layer-by-layer (LBL) assembly of poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA). The effect of temperature on the build-up and post hydrothermal process was studied in detail. It was found that the film's cloudiness was sensitive to the fabrication temperature. Below 20 °C the film was cloudy, while above 25 °C it was transparent. The temperature region from 20–25 °C was a mixed zone, transiting from cloudy to transparent. The thickness growth exhibited different temperature dependencies in the cloudy and transparent temperature regions. In the cloudy temperature region it was 5–6 nm °C−1 per cycle while in the transparent temperature region it was as high as 15–16 nm °C−1. At 50 °C, the film thickness increment of a single deposition step reached to ∼600 nm, which was considered as one of the fastest growth rates in LBL assembly. The post hydrothermal processing of the film was performed in acidic water (pH = 2.0) at temperatures higher than the build-up temperature. As the hydrothermal processing temperature elevated to 90 °C, the Fabry-Pérot fringes gradually disappeared and a morphology full of pits formed, like the film that was prepared by layer-by-layer assembly at 50 °C.
Co-reporter:Hongjun Dai;Junjie Wu;Yongxin Wang;Shuaixia Tan;Songmiao Liang;Bin Jiang;Ning Zhao
Journal of Applied Polymer Science 2011 Volume 122( Issue 5) pp:3000-3006
Publication Date(Web):
DOI:10.1002/app.34113
Abstract
The diffusion of levofloxacin mesylate (MSALVFX) within agarose hydrogels was investigated by an improved refractive-index method. The diffusion coefficient of MSALVFX in infinite dilution (D0) was obtained as 4.01 × 10−6 cm2/s (25°C) through extrapolation according to Kohlrausch's law. The diffusion behavior of MSALVFX under conditions of different solute concentrations, polymer volume fractions, and temperatures was studied in detail. In the considered range of agarose concentrations (0.5–2.5%, w/w), the ratio of Dg to D0 (where Dg is the effective diffusion coefficient of MSALVFX in the agarose hydrogel) decreased from 0.938 to 0.835 because of the retardance effect of agarose fiber. Furthermore, the experimental data were analyzed with the Amsden, Clague and Philips, and Ogston models, and the data fit the Amsden model best. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Xiaolan Yu, Haosen Fan, Hao Wang, Ning Zhao, Xiaoli Zhang, Jian Xu
Materials Letters 2011 Volume 65(17–18) pp:2812-2815
Publication Date(Web):September 2011
DOI:10.1016/j.matlet.2011.05.116
Flower-like polyaniline–polyvinyl alcohol (PANI/PVA) multidimensional architectures assembled from 2D petals were successfully synthesized in the dilute solution of PVA by the oxidation polymerization. PANI/PVA flowers have a diameter of about 2.5 μm and consist of many interlaced sheet petals. Chemical structure and composition of polymerized PANI/PVA were characterized by Fourier transform infrared (FTIR) spectroscopy, Ultraviolet and visible spectroscopy (UV–vis), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In order to research the formation mechanism of the 3D flower-like PANI/PVA, their growth process was followed by measuring the morphological evolutions of products with the different polymerization times. The results showed that the flower-like PANI/PVA originated from sheet petals, which then self-assembled into flower-like microstructures. In addition, the effect of PVA concentration on the morphology of the 3D flower-like PANI/PVA was also investigated.
Co-reporter:Xiaolan Yu, Haosen Fan, Hao Wang, Ning Zhao, Xiaoli Zhang, Jian Xu
Materials Letters 2011 Volume 65(17–18) pp:2724-2727
Publication Date(Web):September 2011
DOI:10.1016/j.matlet.2011.05.051
A novel 2D leaf-like polyaniline with special hierarchical micro/nanostructures, a length of about 3 μm, width of about 2.3 μm and thickness of about 120 nm, has been successfully synthesized in the presence of poly (acrylic acid-co-maleic acid) sodium salt (PAA/MA-SS), which is self-assembled from 2D square nanoplate and 1D nanorods. Its surface consists of highly cross-linked nanorods of approximately 100 nm in length and 30 nm in diameter. In order to investigate the formation mechanism of such 2D leaf-like polyaniline, some micro/nanostructures of polyaniline are synthesized at different polymerization times and the results show that the polyaniline microleaves originate from square nanoplates, which then self-assemble into leaf-like micro/nanostructures with nanorods on the surface.
Co-reporter:Hai-fan Xiang;Shuai-xia Tan;Xiao-lan Yu
Chinese Journal of Polymer Science 2011 Volume 29( Issue 6) pp:
Publication Date(Web):2011 November
DOI:10.1007/s10118-011-1079-x
The acoustical damping property of electrospun polyacrylonitrile (PAN) nanofibrous membranes with different thicknesses and porosities was investigated. The sound absorption coefficients were measured using the impedance tube instrument based on ISO10534-2:1998(E). Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes. Moreover, the sound absorption performance of the perforated panel can be greatly improved by combination with a thin layer of PAN nanofibrous membrane. Traditional acoustical damping materials (foam, fiber) coated with nanofibrous membranes have better acoustical performance in the low and medium frequency range than that of acoustical materials alone. All of the results demonstrate the PAN nanofibrous membrane is a suitable candidate for noise reduction.
Co-reporter:Junjie Wu, Liang Zhang, Yongxin Wang, Yuhua Long, Huan Gao, Xiaoli Zhang, Ning Zhao, Yuanli Cai, and Jian Xu
Langmuir 2011 Volume 27(Issue 22) pp:13684-13691
Publication Date(Web):October 6, 2011
DOI:10.1021/la2027237
In this article, we report a bioinspired approach to preparing stable, functional multilayer films by the integration of mussel-inspired catechol oxidative chemistry into a layer-by-layer (LbL) assembly. A polyanion of poly(acrylic acid-g-dopamine) (PAA-dopamine) bearing catechol groups, a mussel adhesive protein-mimetic polymer, was synthesized as the building block for LbL assembly with poly(allylamine hydrochloride) (PAH). The oxidization of the incorporated catechol group under mild oxidative condition yields o-quinone, which exhibits high reactivity with amine and catechol, thus endowing the chemical covalence and retaining the assembled morphology of multilayer films. The cross-linked films showed excellent stability even in extremely acidic, basic, and highly concentrated aqueous salt solutions. The efficient chemical cross-linking allows for the production of intact free-standing films without using a sacrificial layer. Moreover, thiol-modified multilayer films with good stability were exploited by a combination of thiols-catechol addition and then oxidative cross-linking. The outstanding stability under harsh conditions and the facile functionalization of the PAA-dopamine/PAH multilayer films make them attractive for barriers, separation, and biomedical devices.
Co-reporter:Xiaoying Lu, Zhen Wang, Xiaoli Yang, Xun Xu, Liang Zhang, Ning Zhao, Jian Xu
Surface and Coatings Technology 2011 206(6) pp: 1490-1494
Publication Date(Web):
DOI:10.1016/j.surfcoat.2011.09.031
Co-reporter:Junjie Wu, Songmiao Liang, Hongjun Dai, Xiaoyan Zhang, Xiaolan Yu, Yuanli Cai, Lina Zhang, Ning Wen, Bin Jiang, Jian Xu
Carbohydrate Polymers 2010 Volume 79(Issue 3) pp:677-684
Publication Date(Web):11 February 2010
DOI:10.1016/j.carbpol.2009.09.022
High-strength cellulose/chitin blended hydrogel membranes were fabricated via a solution pre-gelation method. The morphology and structure of the resultant membranes were investigated by SEM, WXRD and FTIR. The mechanical properties and permeability of the membranes were determined by tensile test and in situ UV–visible spectrophotometry. Instead of the loose mesh-like structure and high crystallinity of the common membranes, remarkably dense aggregation structure and low crystallinity of the novel cellulose/chitin membranes were successfully created through the solution pre-gelation process. It effectively promoted the mechanical performance of the hydrogel membranes. Moreover, the structure and properties of the membranes closely depended on the chitin content and pre-gelation temperature. Dynamic rheology studies revealed the gelation-dynamics of the mixed solution accelerated and decelerated with chitin content. ATR-FTIR results indicated nonsolvent-induced phase-separation was the main mechanism for the formation of such membranes with special structure and improved performance.
Co-reporter:Xiaofeng Li, Yang Wang, Liang Zhang, Shuaixia Tan, Xiaolan Yu, Ning Zhao, Guoqiang Chen, Jian Xu
Journal of Colloid and Interface Science 2010 Volume 350(Issue 1) pp:253-259
Publication Date(Web):1 October 2010
DOI:10.1016/j.jcis.2010.06.046
Honeycomb-patterned polyalkylcyanoacrylate (PACA) films were prepared from the chloroform solutions of alkylcyanoacrylate (ACA) by breath figures (BFs) method. Condensed water droplets on the solution surface acted not only as templates to endow the ordered structure but also as initiators to trigger the polymerization of ACA. After the polymerization started, the in situ formed polymer chains self-assembled around the water droplets, structuring PACA film with a hexagonal arrangement of holes. This was the first time that polymerization was introduced to breath figures method. The formation mechanism and the influencing factors, including substrates, relative humidity, and solution concentrations were investigated. Hela cells were cultured on both flat and honeycomb-like PACA films to investigate their application as biomaterials.Graphical abstractHoneycomb-like films were prepared directly from the alkylcyanoacrylate monomer solution via a polymerization involved breath figure method on the hydrophobic polypropylene substrate.Research highlights► Honeycomb-like PACA films are obtained from monomer solution by BFs method ► Water droplets are used as both templates and the initiators ► Ordered porous structure enhances the cell proliferations
Co-reporter:Liang Zhang, Xiaoyan Zhang, Zhen Dai, Junjie Wu, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2010 Volume 345(Issue 1) pp:116-119
Publication Date(Web):1 May 2010
DOI:10.1016/j.jcis.2010.01.044
A micro–nano hierarchically structured nylon 6,6 surface was easily fabricated by phase separation. Nylon 6,6 plate was swelled by formic acid and then immersed in a coagulate bath to precipitate. Micro particles with nano protrusions were generated and linked together covering over the surface. After dried up, the as-formed surface showed superhydrophilic ability. Inspired by lotus only employing 2-tier structure and ordinary plant wax to maintain superhydrophobicity, paraffin wax, a low surface energy material, was used to modify the hierarchically structured nylon 6,6 surface. The resultant surface had water contact angle (CA) of 155.2 ± 1.3° and a low sliding angle. The whole process was carried on under ambient condition and only need a few minutes.Nylon 6,6 surface was covered with hierarchical particles after phase separation. The surface showed superhydrophilicity. After modification, a nearly conformal morphology was generated and the surface was superhydrophobicity.
Co-reporter:Hao Zou, Yan Jin, Jun Yang, Hongjun Dai, Xiaolan Yu, Jian Xu
Separation and Purification Technology 2010 Volume 72(Issue 3) pp:256-262
Publication Date(Web):11 May 2010
DOI:10.1016/j.seppur.2010.01.019
A novel interfacial polymerization approach was used in this study and applied to prepare the thin film composite reverse osmosis (RO) membranes with some excellent properties. The surface of the membranes was characterized by scanning electronic microscopy (SEM), attenuated total reflectance infrared (ATR-IR) and X-ray photoelectronic spectroscopy (XPS). The results indicated that the membranes prepared by novel interfacial polymerization approach have smoother surface than the membranes obtained by traditional interfacial polymerization approach. There is a large amount of amino group (–NH2) on the topmost surface of the active skin layer of the membrane yielded by novel interfacial polymerization approach, comparing to carboxylic acid groups (–COOH) synthesized by traditional interfacial polymerization approach. Moreover, the membrane made by novel interfacial polymerization approach exhibited better antifouling property than that prepared by traditional interfacial polymerization approach. A unique and simple method to prepare thin film composite RO membranes with good membrane performance property was demonstrated.
Co-reporter:Xiaolan Yu, Haifan Xiang, Yuhua Long, Ning Zhao, Xiaoli Zhang, Jian Xu
Materials Letters 2010 Volume 64(Issue 22) pp:2407-2409
Publication Date(Web):30 November 2010
DOI:10.1016/j.matlet.2010.08.006
Polyacrylonitrile (PAN) porous fibers were prepared in one step by electrospinning a ternary system of PAN/N, N-dimethylformamide (DMF)/water at ambient environment. The formation of porous structures was mainly due to the spinodal decomposition phase separation occurred during the electrospinning process. The concentration of PAN varied from 3 to 10 wt.% with the water content changing from 2 to 8 wt.%. When PAN concentration was above 5 wt.%, the composition of the ternary system was close to the “cloud point” and fibers with porous structures were obtained. In addition, the surface tension and viscosity of PAN solutions increased with water which may lead to the diameter increase of the fibers. The Brunauer–Emmett–Teller (BET) surface area of porous PAN nanofibers obtained from 8 wt.% PAN solution containing 7 wt.% of water was 46.4 m2 g−1, which was 3 times higher than that of nonporous PAN nanofibers prepared under the same conditions from a solution without water.
Co-reporter:Zhen Dai;Ning Zhao;Haosen Fan;Liang Zhang;Xiaoli Zhang
Journal of Applied Polymer Science 2010 Volume 117( Issue 5) pp:2497-2505
Publication Date(Web):
DOI:10.1002/app.32129
Abstract
An incompletely condensed polyvinylsilsesquioxane (PVSQ) oligomer containing abundant silanol groups was synthesized and characterized by FTIR, 1H-NMR, 29Si-NMR, and MALDI-TOF-MS. Polystyrene/polyvinylsilsesquioxane (PS/PVSQ) hybrid composites were prepared by an in situ bulk polymerization. The hybrid composites showed higher Tg, Td, and char yield than PS homopolymer and without mechanical loss. The improvements in the properties of PS/PVSQ hybrid composites can be ascribed to the crosslinking function of PVSQ by silanol condensation in later processing. The hybrids showed different morphology from discrete microstructure to continuous network depending on the concentration of PVSQ. Because of the surface enrichment, a PVSQ protection layer was formed, which made the hybrid surface more hydrophobic. The structure and the reaction mechanism of PS/PVSQ hybrid composites were also investigated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Xiao-yan Zhang;Chun-ting Duan;Ning Zhao;Hong Xiao
Chinese Journal of Polymer Science 2010 Volume 28( Issue 5) pp:841-847
Publication Date(Web):2010 September
DOI:10.1007/s10118-010-0044-4
A newly natural fine template, kapok fiber, for microtube preparation was reported. Large scale microtubes with high length/diameter ratio and controllable wall thickness and morphology have been successfully fabricated with this template. It is a wildly available, low-cost, environmental friendly and fine structured natural template for microtubes. Its thin wall thickness is only about 1–2 μm that means the whole template material is tiny and easy for removing. Even there is any residue the amount can be ignored. When the template is covered with a shell component, hollow structured microtube could be obtained by removing the thin inner template, and its shape could be the same as that of the original template (positive copy of the template’s shape). The products have high length/diameter ratio and uniform tubular structure. By further modifying the fabricating methods, facile fabrication not only exists for polypyrrole (PPy) in electrochemical deposition, but also for many other organic and inorganic materials. The surface morphology and wall thickness of the resultant microtubes can be easily modulated by controlling the processing conditions. This natural fiber is predicted to be a fine template for fabricating large scale microtubes with large cavity and high length/diameter ratio.
Co-reporter:Hongjun Dai, Xiaofeng Li, Yuhua Long, Junjie Wu, Songmiao Liang, Xiaoli Zhang, Ning Zhao and Jian Xu
Soft Matter 2009 vol. 5(Issue 10) pp:1987-1989
Publication Date(Web):06 Apr 2009
DOI:10.1039/B821363A
Multi-membrane hydrogels are newly promising carriers in biomedical fields. We fabricate alginate-based onion-like multi-membrane hydrogels starting from a template gel-core to shells through a dynamic self-assembly method, and investigate the influence of various factors on the formation of the complex system in detail. By precisely controlling the process of preparation, multi-layered hydrogels of different shapes either with or without defined internal space between separated layers can be prepared. And a pulse-like delivery of macromolecule has been achieved by this architecture.
Co-reporter:Xiaofeng Li, Hongjun Dai, Shuaixia Tan, Xiaoyan Zhang, Haiyun Liu, Yongxin Wang, Ning Zhao, Jian Xu
Journal of Colloid and Interface Science 2009 Volume 340(Issue 1) pp:93-97
Publication Date(Web):1 December 2009
DOI:10.1016/j.jcis.2009.08.017
Hollow microspheres of poly(ethyl α-cyanoacrylate) were prepared via vapor phase polymerization using micro-waterdroplets as template and initiator. Depending on the ratio of the shell thickness to the radius, the hollow microspheres would crimple to form either microballoons or microcups during drying. These two types of microparticles were used as building blocks to construct surfaces with diverse wettability. The microballoons linked up to form a porous-netlike surface which was rough enough to render the surface superhydrophobic, while the microcups-built surface showed less hydrophobicity. In addition, surfaces consisting of both microparticles with gradual decrease of roughness along the length direction were obtained, which presented gradient wetting property varied from superhydrophobic to hydrophobic. The as-formed superhydrophobic or gradient wetting surfaces may find potential applications in biomedical field because of the biocompatibility of poly(ethyl α-cyanoacrylate).The hollow microspheres of poly(ethyl α-cyanoacrylate) were prepared one-step by vapor phase polymerization and then deformed to construct surface with gradient roughness corresponding to wetting gradient from superhydrophobic to hydrophobic.
Co-reporter:Zhen Dai, Yanfang Li, Shuguang Yang, Ning Zhao, Xiaoli Zhang, Jian Xu
European Polymer Journal 2009 Volume 45(Issue 7) pp:1941-1948
Publication Date(Web):July 2009
DOI:10.1016/j.eurpolymj.2009.04.012
The fluorene-containing epoxy, diglycidyl ether of 9,9-bis(4-hydroxyphenyl) fluorene (DGEBF) was synthesized by a two-step reaction procedure. In order to investigate the relationship between fluorene structure and material properties, DGEBF and a commonly used diglycidyl ether of bisphenol A (DGEBA) were cured with 4,4-diaminodiphenyl methane (DDM) and 4,4-(9-fluorenylidene)-dianiline (FDA). The curing kinetics, thermal properties and decomposition kinetics of these four systems (DGEBA/DDM, DGEBF/DDM, DGEBA/FDA, and DGEBF/FDA) were studied in detail. The curing reactivity of fluorene epoxy resins was lower, but the thermal stability was higher than bisphenol A resins. The onset decomposition temperature of cured epoxy resins was not significantly affected by fluorene structure, but the char yield and Tg value were increased with that of fluorene content. Our results indicated that the addition of fluorene structure to epoxy resin is an effective method to improve the thermal properties of resins, but excess fluorene ring in the chain backbone can depress the curing efficiency of the resin.
Co-reporter:Yanfang Li;Shuguang Yang;Haiyun Liu;Xiaofeng Li;Zhen Dai;Ning Zhao
Journal of Applied Polymer Science 2009 Volume 111( Issue 3) pp:1454-1461
Publication Date(Web):
DOI:10.1002/app.28943
Abstract
A composite film of polymethylsilsesquioxane (PMSQ) and hydroxyl-terminated polydimethylsiloxane (PDMS) was prepared by incubating PMSQ prepolymer and PDMS solution in a vapor environment before thermal curing. Vapor incubation has a significant influence on the morphology and properties of the cured composite, and the vapor incubation was conducted under three different conditions, i.e., acidic, neutral, and basic. In the acidic vapor of a pH rather lower than the isoelectric point (IEP) of the silanol, the reaction between PMSQ and PDMS through silanol condensation was promoted by the protonation of silanol. PDMS rubber particles with a domain size of about 100 nm were formed in PMSQ matrix, and the flexible modulus of the film was improved. While, the morphology of the resultant film was smooth and uniform after incubation in a neutral water vapor. The basic vapor facilitated the gelation of composite due to high pH inducing more rapid silanol condensation in PMSQ than phase separation. Moreover, excellent optical transparency, insulation, and thermal stability of the composite were also retained after the PDMS incorporation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Xiaoyan Zhang;Xinglin Guo;Shuguang Yang;Shuaixia Tan;Xiaofeng Li;Hongjun Dai;Xiaolan Yu;Xiaoli Zhang;Ning Weng;Bin Jian
Journal of Applied Polymer Science 2009 Volume 112( Issue 5) pp:3063-3070
Publication Date(Web):
DOI:10.1002/app.29572
Abstract
Novel double-network (DN) hydrogels with high mechanical strength have been fabricated with two biocompatible polymers, poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG), through a simple freezing and thawing method. Some properties of the obtained hydrogels, such as the mechanical strength, rheological and thermodynamic behavior, drug release, and morphology, have been characterized. The results reveal that in sharp contrast to most common hydrogels made with simple natural or synthetic polymers, PVA/PEG hydrogels can sustain a compressive pressure as high as several megapascals, highlighting their potential application as biomedical materials. In addition, a model for describing the structural formation of PVA/PEG DN hydrogels is proposed: the condensed PVA-rich phase forms microcrystals first, which bridge with one another to form a rigid and inhomogeneous net backbone to support the shape of the hydrogel, and then the dilute PEG-rich phase partially crystallizes among the cavities or voids of the backbone; meanwhile, there are entanglements of molecular chains between the two polymers. Moreover, a mechanism is also proposed to explain the high mechanical strength of PVA/PEG DN hydrogels. It is suggested that the free motion of PEG clusters in the cavities of PVA networks can prevent the crack from growing to a macroscopic level because the linear PEG chains in the cavities effectively absorb the crack energy and relax the local stress either by viscous dissipation or by large deformation of the PEG chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Shuguang Yang, Yanfang Li, Xiaofeng Li, Yuefang Li, Xiaoli Zhang, Jian Xu
Thin Solid Films 2009 Volume 517(Issue 9) pp:3024-3027
Publication Date(Web):2 March 2009
DOI:10.1016/j.tsf.2008.12.001
The hydrogen-bonded films of poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) were fabricated using layer-by-layer assembly technique. The films were incubated at three different vapor environments (acidic, neutral and basic). PAA would ionize in neutral or basic vapor environment, and then hydrogen bonds linking PVPON and PAA in the film would break and patterned topography would form gradually. Ionization degree of PAA in the film was characterized by Fourier transform infrared spectroscopy. Optical microscope and atomic force microscope were used to observe the film morphologies before and after incubation. Reflective spectroscopy and contact angle measurements were applied to further characterize the patterned surfaces.
Co-reporter:Xiaoyan Zhang;Ning Zhao;Songmiao Liang;Xiaoying Lu;Xiaofen Li;Qiongdan Xie;Xiaoli Zhang
Advanced Materials 2008 Volume 20( Issue 15) pp:2938-2946
Publication Date(Web):
DOI:10.1002/adma.200800626
Co-reporter:Shuaixia Tan, Qiongdan Xie, Xiaoying Lu, Ning Zhao, Xiaoli Zhang, Jian Xu
Journal of Colloid and Interface Science 2008 Volume 322(Issue 1) pp:1-5
Publication Date(Web):1 June 2008
DOI:10.1016/j.jcis.2008.02.066
Brassica oleracea-like polymer surface is facilely fabricated by one-step casting process using amorphous polystyrene (PS) under ambient atmosphere. The obtained coatings show excellent superhydrophobicity and only possess unitary micro-scale structure, similar to the natural brassica leaf. In addition, a simple topography analysis also roughly verifies superhydrophobic structure of branched and intermingled sticks and bumps. This process provides a fairly easy procedure for preparing superhydrophobic surface from common plastics. Moreover, it demonstrates that the micro/nano-binary structure is not necessary for superhydrophobicity, while unitary micro-scale structure for a polymer surface can exhibit outstanding water repellency as natural lotus.Brassica oleracea-like polymer surface is facilely fabricated by one-step casting process using amorphous polystyrene (PS) under ambient atmosphere. Moreover, a simple topography analysis verifies roughly superhydrophobic microstructure.
Co-reporter:Shuguang Yang, Shuaixia Tan, Yongjun Zhang, Jian Xu, Xiaoli Zhang
Thin Solid Films 2008 Volume 516(Issue 12) pp:4018-4024
Publication Date(Web):30 April 2008
DOI:10.1016/j.tsf.2007.08.010
Thin films were fabricated from poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) based on hydrogen bonding layer-by-layer (LBL) assembly process. Due to light interference, PVPON/PAA films present Fabry–Pérot fringes in the UV–Vis–NIR spectrum. LBL assembly constructed the film on both sides of substrate (double-side film), which are different to traditional vacuum deposition that forms the film only on one side of substrate (single-side film). The light interference processes of the double-and single-side films were fully analyzed. Using the peak positions and amplitude of the Fabry–Pérot fringes, the refractive index and thickness of the film can be evaluated. Furthermore, Fabry–Pérot fringes can be utilized to monitor the film's growth and water content variation in the film.
Co-reporter:N. Zhao;Q. Xie;X. Kuang;S. Wang;Y. Li;X. Lu;S. Tan;J. Shen;X. Zhang;Y. Zhang;J. Xu;C. C. Han
Advanced Functional Materials 2007 Volume 17(Issue 15) pp:
Publication Date(Web):21 AUG 2007
DOI:10.1002/adfm.200601012
In this study, we report the fabrication of a novel surface with both morphology and composition heterogeneities by casting polymer blend solution. The resultant poly (methyl methacrylate) (PMMA) and amphiphilic polyurethane (A-PU) surface has a rough structure on microscale and separated hydrophobic and hydrophilic nanodomains as well. On this surface, water drop shows a static CA about 160° but the drop is pinned on the surface at any titled angles. This phenomenon can be ascribed to the special surface characters as the air trapped in the porous surface and hydrophobic domains repel the water, leading to a very high static CA, whereas the hydrophilic domains contacting with water at the interface, though being restrained to a little fraction by the surface roughness, adhere the drop. In addition, by adding the third component, hydrophobic fluorinated polyurethane, in the blend, the formed PMMA/A-PU/F-PU blend surfaces show CA about 160° but the SA be able to rationally tune from small to large by adjusting the ratio of A-PU to F-PU. Our method provides a novel approach for controlling surface morphology, composition and corresponding surface adhesion, and may find many applications in various fields.
Co-reporter:Shuguang Yang, Yongjun Zhang, Xiaoli Zhang and Jian Xu
Soft Matter 2007 vol. 3(Issue 4) pp:463-469
Publication Date(Web):14 Dec 2006
DOI:10.1039/B615260K
A detailed study of the influence of pH on the hydrogen-bonding layer-by-layer (LBL) assembly film constructed from poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) was carried out. It was found that the LBL assembly process of a PVPON–PAA film is very sensitive to pH. pH 4.0 is the critical value for film build-up: at pH values above 4.0, the assembly of PVPON and PAA is almost halted, whereas for pH < 4.0, PVPON and PAA can be successfully deposited. For pH < 4.0, there are two transitions in the plot of film thickness as a function of pH value, and pH can affect the film thickness greatly, from several angstroms to hundreds of nanometres per dipping cycle. Moreover, pH also affects the morphology of the films and the composition of PVPON and PAA in the film. The influence of pH upon the PVPON–PAA film can be considered as a consequence of the pH-induced charge density and the conformation change of PAA. In addition, the pH discrepancy between the build-up and disintegration of the hydrogen-bonded film is discussed, and pH 5.5 can be considered to be the onset value of disintegration of the PVPON–PAA film, which is higher than the critical pH value of build-up (pH 4.0).
Co-reporter:Xiaoying Lu, Shuaixia Tan, Ning Zhao, Shuguang Yang, Jian Xu
Journal of Colloid and Interface Science 2007 Volume 311(Issue 1) pp:186-193
Publication Date(Web):1 July 2007
DOI:10.1016/j.jcis.2007.02.066
A low-density polyethylene (LDPE) surface with a sharp wettability gradient and high hysteresis was prepared, on which a unique behavior of water drops was found. The water contact angle of one water drop on the less hydrophobic region was larger than that on the more hydrophobic end, which was much different from the general phenomenon. The unique behavior is believed to be induced by the high hysteresis of the LDPE surface and the sharp change in wettability. The driving and hysteresis forces acting on the water drops were calculated and analyzed in detail. The reasons resulting to such a unique phenomenon were further explained.The water CA of the middle water drop on the less hydrophobic region was larger than that on the more hydrophobic end, which was much different from the general phenomenon.
Co-reporter:Zhen Dai;Shuguang Yang;Chengzhong Zong;Yanfang Li;Xukui Lu
Journal of Applied Polymer Science 2007 Volume 106(Issue 3) pp:1476-1481
Publication Date(Web):12 JUL 2007
DOI:10.1002/app.26585
Diglycidyl ether of 9,9-bis(4-hydroxyphenyl) fluorene (DGEBF) was synthesized to introduce more aromatic structures into an epoxy resin system. The structure of DGEBF was characterized with Fourier transform infrared and 1H-NMR. 4,4′-Diaminodiphenylmethane (DDM) was used as the curing agent for DGEBF, and differential scanning calorimetry was applied to study the curing kinetics. The glass-transition temperature of the cured DGEBF/DDM, determined by dynamic mechanical analysis, was 260°C, which was about 100°C higher than that of widely used diglycidyl ether of bisphenol A (DGEBA). Thermogravimetric analysis was used to study the thermal degradation behavior of the cured DGEBF/DDM system: its onset degradation temperature was 370°C, and at 700°C, its char yield was about 27%, whereas that of cured DGEBA/DDM was only 14%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Co-reporter:Songmiao Liang;Yanfang Li;Lina Zhang
Macromolecular Chemistry and Physics 2007 Volume 208(Issue 6) pp:594-602
Publication Date(Web):22 MAR 2007
DOI:10.1002/macp.200600579
By employing a pre-gelation processing of cellulose solution, this work has presented a new method to prepare cellulose hydrated membranes in NaOH/thiourea aqueous solvent system. The morphology and structure of the hydrated membranes obtained at different pre-gelation temperatures were studied by scanning electron microscopy (SEM), wide-angle X-ray diffractometry (WAXD), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the membranes were studied by tensile testing. Using a double-cell method, permeation of three model drugs (ceftazidine, cefazolin sodium, thiourea) through the hydrate membranes was determined in phosphate buffer solution at body-like temperature (37 °C). The results indicate that the membranes were packed densely by many hydrated nanospheres and exhibited good mechanical properties. At a relatively low pre-gelation temperature, the strain and the stress at break of the membranes are even up to 192% and 1.97 MPa, which are much larger than that of the hydrated membranes prepared by the general solution casting method. For the first time, the formation process of the hydrated membrane from gel state in water was investigated by ATR-FTIR spectrum, indicating a non-solvent-induced phase-separation mechanism.
Co-reporter:Songmiao Liang;Lina Zhang;Yanfang Li
Macromolecular Chemistry and Physics 2007 Volume 208(Issue 6) pp:
Publication Date(Web):27 MAR 2007
DOI:10.1002/macp.200790010
Cover: The picture illustrates a strategy for the preparation of cellulose hydrated membrane via pre-gelation processing and the interesting surface and bulk structure of the membrane. Further details can be found in the Full Paper S. Liang, L. Zhang,* Y. Li, and J. Xu* on page 594.
Co-reporter:Shuguang Yang;Yongjun Zhang ;Xiaoyan Zhang ;Ying Guan Dr.;Xiaoli Zhang
ChemPhysChem 2007 Volume 8(Issue 3) pp:418-424
Publication Date(Web):20 DEC 2006
DOI:10.1002/cphc.200600595
The cloudiness of hydrogen-bonded LBL films assembled from polyvinylpyrrolidone (PVPON) and poly(acrylic acid) (PAA) is studied in detail by two approaches: spectroscopy (Fabry–Pérot fringes) and microscopy (AFM). Fabrication parameters such as temperature, molecular weight, pH value, and rinsing time, have notable influences on film cloudiness. The buildup of the PVPON/PAA film is a two-stage process of adsorption and chain rearrangement. Generally, adsorption is fast, while chain rearrangement is slow. The fast adsorption process traps defects, whereas the relatively slow chain-rearrangement process can not heal the defects in time; therefore, the number of defects continuously increases as LBL assembly proceeds, and a cloudy, heterogeneous film is produced. However, the as-prepared cloudy films become transparent and homogeneous on subsequent annealing in acidic water. UV/Vis spectroscopy and fluid AFM were applied to monitor this transition ex situ and in situ, respectively. It is found that increasing the annealing temperature accelerates the transition from cloudy to transparent, and the transition of the film made from higher molecular weight polymer is slower.
Co-reporter:Songmiao Liang;Lihui Weng;Lina Zhang;Xinglin Guo;Xiaoli Zhang
Journal of Polymer Science Part B: Polymer Physics 2007 Volume 45(Issue 10) pp:1187-1197
Publication Date(Web):9 APR 2007
DOI:10.1002/polb.21126
A electromechanical gel, which could be driven in air by a DC electric field, was developed using poly(vinyl alcohol)/dimethylsulfoxide gel. When the applied electric field exceeds a certain threshold, the gel exhibited a continuous and linear crawling motion. The result indicated that, under the applied electric field of 275 V/mm, the maximum crawling velocity of the gel could reach v = 1.63 mm/s, which is about 80 times larger than that reported in earlier works. At a proper range of the driving time, the average crawling speed and crawling direction could be well controlled by the external electric field. Furthermore, some factors, which have influence on the critical driving electric field of the gel, such as the swelling degree of the gel and the apparent contact area between the gel and substrate, were studied. For the first time, a mechanism based on the strong electrostatic interaction between the external electric field and the charges accumulated in the gel–air and substrate–gel interfacial regions was put forward to explain the novel motion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1187–1197, 2007
Co-reporter:Ning Zhao;Xiao-Yan Zhang;Yan-Fang Li;Xiao-Ying Lu
Cell Biochemistry and Biophysics 2007 Volume 49( Issue 2) pp:91-97
Publication Date(Web):2007 October
DOI:10.1007/s12013-007-0044-3
Nature always gives us inspirations to fabricate functional materials by mimicking the structure design of biomaterials. In this article, we report that polymeric aggregates with morphology similar to the papilla on lotus leaf can be self-organized in the polymer solution by adding 16 wt% water into 5 mg/ml polycarbonate solution in N, N′-dimethylformamide. The hierarchically structured aggregates at micro- and nano-scale alone show superhydrophobic effect without the need of modification with low surface energy compound. Small amount of liquid can be wrapped by the aggregates to form the so-called liquid marble. Influence of the amount of water added into the solution on the morphology of resultant polymer aggregates was investigated. By using the hierarchical aggregates as the surface building blocks, superhydrophobic coating with a static water contact angle larger than 160° and sliding angle less than 5° (for a water drop of 5 μl) was formed. Other solutions, like acid, basic and blood plasma are also repelled on the coating.
Co-reporter:Jian Xu ;Songmiao Liang;Lihui Weng Dr.;Lina Zhang ;Xiaoli Zhang;Xinglin Guo Dr.
ChemPhysChem 2007 Volume 8(Issue 6) pp:899-905
Publication Date(Web):15 MAR 2007
DOI:10.1002/cphc.200600745
Herein, we report a special poly(vinyl alcohol)/dimethylsulfoxide (PVA/DMSO) gel electromechanical system with great self-governed capability. The system is operated in air by applying a noncontacted DC electric field. When the applied electric field exceeds a certain critical value, the gel exhibits fast and self-governing locomotion on the gradiently charged glass substrate. In contrast to field-controlled gel systems developed earlier, the crawling direction of the gel is independent of the direction of the applied electric field and can be actively controlled. The maximum crawling velocity can reach 3.22 mm s−1, which is much larger than that of the actuators described earlier. Furthermore, some factors that influence the critical driving electric field and the average crawling speed of the gel were studied. The mechanism analysis indicates that, the self-governing linear motion of the gel is due to the spatially and temporally varying electrostatic interaction between the gel and the applied electric field in response to the gradient change of the charge density and the charge polarity on the substrate.
Co-reporter:Ning Zhao Dr.;Xiaoyan Zhang;Xiaoli Zhang
ChemPhysChem 2007 Volume 8(Issue 7) pp:1108-1114
Publication Date(Web):16 APR 2007
DOI:10.1002/cphc.200700032
A simple method is described for controlling the surface chemical composition and topography of the diblock copolymer poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) by casting the copolymer solutions from solvents with different selectivities. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively, and the wetting behavior was studied by water contact angle (CA) and sliding angle (SA) and by CA hysteresis. Chemical composition and morphology of the surface depend on solvent properties, humidity of the air, solution concentration, and block lengths. If the copolymer is cast from a common solvent, the resultant surface is hydrophobic, with a flat morphology, and dominated by PDMS on the air side. From a PDMS-selective solvent, the surface topography depends on the morphology of the micelles. Starlike micelles give rise to a featureless surface nearly completely covered by PDMS, while crew-cut-like micelles lead to a rough surface with a hierarchical structure that consists partly of PDMS. From a PS-selective solvent, however, surface segregation of PDMS was restricted, and the surface morphology can be controlled by vapor-induced phase separation. On the basis of the tunable surface roughness and PDMS concentration on the air side, water repellency of the copolymer surface could be tailored from hydrophobic to superhydrophobic. In addition, reversible switching behavior between hydrophobic and superhydrophobic can be achieved by exposing the surface to solvents with different selectivities.
Co-reporter:Songmiao Liang, Jian Xu, Lihui Weng, Hongjun Dai, Xiaoli Zhang, Lina Zhang
Journal of Controlled Release 2006 Volume 115(Issue 2) pp:189-196
Publication Date(Web):10 October 2006
DOI:10.1016/j.jconrel.2006.08.006
The accurate knowledge of the diffusion behavior of protein within biomimetic hydrogel matrix at body temperature has a great implication for the design of efficient controlled release protein-base drug delivery devices. In this paper, we improved our previous in situ refractive index method with great temperature-controlled capability. For the first time, this newly improved method was employed to study the diffusion of protein (bovine serum albumin (BSA) and lysozyme) in agarose hydrogel at body temperature (37 °C). The change of the gel refractive index caused by the change of the diffusing protein concentration within the gel during the diffusion process enables the effective diffusion coefficients of protein to be estimated. The diffusion coefficients of proteins decrease with the increase of the concentration of agarose and the solute molecular size. At the considered range of agarose concentration (0.5–3.0 wt.%), the diffusion coefficients range from 4.98 to 8.21 × 10− 7 cm2/s for BSA and 1.15 to 1.56 × 10− 6 cm2/s for lysozyme, respectively. Temperature dependence of diffusivity of BSA in agarose hydrogel was also investigated. Furthermore, the retardance effect of polymer volume fraction on the diffusivity of both BSA and lysozyme in agarose hydrogels was analyzed with three models, Amsden's, Clauge and Philips', and Ogsten's model.
Co-reporter:Yanfang Li;Haiyun Liu;Baiyu Li;Jun Ma;Xiaoli Zhang
Macromolecular Rapid Communications 2006 Volume 27(Issue 18) pp:1603-1607
Publication Date(Web):20 SEP 2006
DOI:10.1002/marc.200600372
Summary: A simple method for the fabrication of a chemical composition gradient from organic to inorganic by the pyrolysis of a polymethylsilsesquioxane (PMSQ) thin film in a gradient temperature field is reported. The resultant chemical gradient surface demonstrates gradual changes in wettability, and slight microstructural changes are observed along the substrate.
Co-reporter:Shuguang Yang, Yongjun Zhang, Ying Guan, Shuaixia Tan, Jian Xu, Shijing Cheng and Xiaoli Zhang
Soft Matter 2006 vol. 2(Issue 8) pp:699-704
Publication Date(Web):29 Jun 2006
DOI:10.1039/B606923A
Hydrogen-bonded films of poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) were built on a silicon and quartz surface using the layer-by-layer (LBL) assembly technique. Upon incubation, PVPON and PAA chains in the film can attain high-level miscibility and the film becomes homogeneous and transparent. TGA and elemental analysis indicate that the water content of the incubated PVPON–PAA film is only ∼4%. FT-IR proved that at high temperature these water molecules can be easily driven out of the film. When the incubated film was characterized with a spectrometer, it exhibited Fabry–Pérot fringes in the UV–visible–NIR spectrum. Such Fabry–Pérot fringes, sensitive to the change of water content in the film, were applied to study drying, drying–rewetting cycle, and humidity-responsive behavior of the film. The film exhibited reversible swelling–deswelling behavior during the incubation–heating cycles. The film thickness was found to decrease ∼10% upon drying. When the dry film was exposed to different humidity environments, it was found that the optical thickness of the film has a linear relationship with ambient humidity.
Co-reporter:Bai-Yu Li;Jun Ma;Hai-Yun Liu;Xing-Lin Guo;Xiao-Li Zhang
Journal of Applied Polymer Science 2006 Volume 100(Issue 5) pp:3974-3980
Publication Date(Web):27 MAR 2006
DOI:10.1002/app.23018
To achieve good compatibility between clay layers and siloxane polymer, polymethylsilsesquioxane (PMSQ), montmorillonite was modified by a novel siloxane surfactant with M̄w = 1900 and then environmentally friendly solution-compounded with PMSQ to prepare glass fiber laminates. Transmission electronic microscope shows the orderly, exfoliated structure of the modified clay in PMSQ matrix; scanning electronic microscope demonstrates the fine dispersion of the clay layers in the matrix because of the good compatibility between the grafted surfactant and the matrix. Both the modified clay and its nanocomposite indicate much improved thermal stability. By incorporation of merely 0.3 wt % of the clay, the flexural modulus and strengths of fiber/PMSQ laminate are increased by 21 and 62%, respectively. This study illuminates the importance of the compatibility of the grafted siloxane surfactant with the matrix polymer in achieving both exfoliation and dispersion of clay as well as ideal mechanical properties for silicone-based polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3974–3980, 2006
Co-reporter:Lihui Weng Dr. ;Xiaoyan Zhang;Xiaoli Zhang;Ning Zhao;Qiongdan Xie
ChemPhysChem 2006 Volume 7(Issue 4) pp:824-827
Publication Date(Web):9 MAR 2006
DOI:10.1002/cphc.200500698
Natural inspiration: A lotus-leaf-like hierarchical structure is formed on a polycarbonate plate under mild conditions by successive plasticization and coagulation of the polymer surface. The resultant micron- and nanoscale rough structure, shown in the figure allows the common plastic to be superhydrophobic with a large water contact angle and less contact angle hysteresis.
Co-reporter:Xiaoyan Zhang;Shuaixia Tan;Ning Zhao Dr.;Xinglin Guo Dr.;Xiaoli Zhang Dr.;Yongjun Zhang
ChemPhysChem 2006 Volume 7(Issue 10) pp:2067-2070
Publication Date(Web):29 AUG 2006
DOI:10.1002/cphc.200600229
An exceptional evaporation pattern is observed on special micro–nano hierarchically structured superhydrophobic natural lotus and biomimetic polymer surfaces. The evaporation process is simulated by the ellipsoidal cap-geometry model, which fits the experimental data well. The picture shows the contact angle (CA) and the height (h) of a water droplet on a natural lotus surface versus the evaporation time based on the ellipsoidal (+) and spherical (×) models.
Co-reporter:Jian Xu;Qiongdan Xie;Xinglin Guo;Ning Zhao;Lianghe Shi;Lihui Weng;Xiaoli Zhang;Ning Zhao;Lihui Weng;Qiongdan Xie;Xinglin Guo;Xiaoli Zhang;Lianghe Shi
Macromolecular Rapid Communications 2005 Volume 26(Issue 13) pp:1075-1080
Publication Date(Web):22 JUN 2005
DOI:10.1002/marc.200500188
Summary: A superhydrophobic coating was facilely fabricated in one step by casting bisphenol A polycarbonate (PC) solution under moisture. Vapor-induced phase separation occurred during the solidifying process and a rough surface with a micro-nano-binary structure (MNBS) similar to the microstructure shown on lotus leaf was formed.
Co-reporter:Xinhua Dai, Zhimin Liu, Yong Wang, Guanying Yang, Jian Xu, Buxing Han
The Journal of Supercritical Fluids 2005 Volume 33(Issue 3) pp:259-267
Publication Date(Web):March 2005
DOI:10.1016/j.supflu.2004.08.003
Foaming of polyurethane (PU) films using supercritical CO2 as a blowing agent, a “green” and high-efficient approach, has been studied. Microcellular foam material was prepared by saturating the polymer with CO2 and its morphology was characterized by scanning election microscopy (SEM). The influence of processing parameters, such as pressure, temperature and soaking time, on the foam morphology was investigated. It was found that the size and distribution of the micro-cell could be controlled conveniently by changing the processing conditions. The results of dynamic mechanical temperature analysis (DMTA) showed that the damping property of the foamed materials was greatly improved and had a maximum value, tan δ = 3.88 at 63 Hz due to the properties of the storage and loss moduli compared with the original PU. Reduction of the mass density led to a decline in the mechanical properties of the foamed materials.
Co-reporter:Q. Xie;G. Fan;N. Zhao;X. Guo;J. Xu;J. Dong;L. Zhang;Y. Zhang
Advanced Materials 2004 Volume 16(Issue 20) pp:
Publication Date(Web):8 NOV 2004
DOI:10.1002/adma.200400074
A super-hydrophobic surface (see Figure), possessing a microscale and nanoscale hierarchical structure similar to the surface structure of the lotus leaf, was prepared in one step from a micellar solution of polypropylene-block-poly(methyl methacrylate).
Co-reporter:Q. Xie;J. Xu;L. Feng;L. Jiang;W. Tang;X. Luo;C. C. Han
Advanced Materials 2004 Volume 16(Issue 4) pp:
Publication Date(Web):26 FEB 2004
DOI:10.1002/adma.200306281
Co-reporter:Xinhua Dai, Zhimin Liu, Buxing Han, Zhenyu Sun, Yong Wang, Jian Xu, Xinglin Guo, Ning Zhao and Jing Chen
Chemical Communications 2004 (Issue 19) pp:2190-2191
Publication Date(Web):18 Aug 2004
DOI:10.1039/B407605B
Poly(2,4-hexadiyne-1,6-diol)
(poly(HDiD)) was coated on the outer walls of carbon nanotubes (CNTs) with the aid of supercritical CO2, resulting in poly(HDiD)/CNT nanocomposites, which possess optical properties originated from poly(HDiD).
Co-reporter:Y. Zhang;Y. Guan;S. Yang;J. Xu;C.C. Han
Advanced Materials 2003 Volume 15(Issue 10) pp:
Publication Date(Web):16 MAY 2003
DOI:10.1002/adma.200304315
Co-reporter:Xianju Zhou;Lihui Weng;Qiang Chen;Jianming Zhang;Deyan Shen;Zhuchuan Li;Manjun Shao
Polymer International 2003 Volume 52(Issue 7) pp:
Publication Date(Web):19 JUN 2003
DOI:10.1002/pi.1207
It was found that the upper critical solution temperature (UCST) of poly(acrylic acid-co-acrylamide) hydrogel decreases with increase in pH. The UCST of samples equilibrated in a buffer at pH 2.5 was 33.7 °C, whereas it shifted to below 0 °C when swollen in buffers above pH 10. FT-IR showed that COOH group of acrylic acid ionized gradually in alkaline media. The morphology change of the hydrogel swollen in different buffers was studied by environmental scanning electron microscopy (ESEM). ESEM images showed that the pore size of the sample increased with increase in pH, and in strongly basic media the three-dimensional network was replaced by a ‘sausage-like’ or ‘desert-like’ structure. A study of the pH-dependent release of cefazolin sodium was also carried out. Copyright © 2003 Society of Chemical Industry
Co-reporter:Xianju Zhou;Deyan Shen;Lihui Weng;Jianming Zhang
Journal of Polymer Science Part B: Polymer Physics 2003 Volume 41(Issue 19) pp:2290-2295
Publication Date(Web):13 AUG 2003
DOI:10.1002/polb.10498
A novel transmittance change of poly(acrylamide-co-acrylic acid) hydrogel in a DC electric field was observed. Transmittance of a specimen increased when the electric field was on and decreased by removing the electric force. In certain cases, the sample was able to switch from white opaque to colorless transparent. The rate and extent of the transition depended on the applied electric potential, ambient temperature, and composition of the specimen. These observations are closely related to the dissociation of hydrogen bonding in the network induced by an external electric field. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2290–2295, 2003
Co-reporter:Haosen Fan, Hong Yu, Yufei Zhang, Jing Guo, Zhen Wang, Hao Wang, Xi Hao, Ning Zhao, Hongbo Geng, Zhengfei Dai, Qingyu Yan, Jian Xu
Nano Energy (March 2017) Volume 33() pp:
Publication Date(Web):March 2017
DOI:10.1016/j.nanoen.2017.01.043
•Hierarchical yolk shell structures assembled from ZnO@C nanocrystals were successfully prepared from zinc-cyanide hybrid coordination polymers.•The micro-nano secondary structure can both achieve high packing density and facilitate the Li+ ion diffusion.•The yolk-shell structure exhibit ultra-stable cycle life because it can further buffer the strain during repeated cycling to maintain the structural integrity.Uniform zinc-cyanide hybrid coordination polymer microspheres were successfully synthesized by a coprecipitation method. Then hierarchical yolk-shell structured and carbon coated ZnO microspheres (YC-ZnO) composed of ZnO@C nanocrystals were prepared by consecutive post annealing processes of these microspheres in argon and air atmosphere. Such micro-nano porous structures have the advantages of large specific surface area, good charge transport kinetics, and large cavity to accommodate the volume change and maintain the mechanical integrity of the electrode material. When evaluated as anode materials of lithium ion batteries, these ZnO yolk-shell spheres exhibited excellent battery performance with a high rate capacity and ultra-stable cycling stability.
Co-reporter:Dong Wang, Jing Guo, Huan Zhang, Beichen Cheng, Heng Shen, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 24) pp:NaN12872-12872
Publication Date(Web):2015/05/11
DOI:10.1039/C5TA01915J
A strategy for combining covalent and non-covalent cross-links to construct multifunctional rubber materials with intelligent self-healing and shape memory ability is demonstrated. Rubbers were prepared by self-assembly of complementary polybutadiene oligomers bearing carboxylic acid and amine groups through reversible ionic hydrogen bonds via the acid–base reaction, and then further covalently cross-linked by tri-functional thiol via the thiol-ene reaction. The resulting polymers exhibit self-healing and shape memory functions owing to the reversible ionic hydrogen bonds. The covalent cross-linking density can be tuned to achieve tailorable mechanical and stimuli-responsive properties: a low covalent cross-linking density maintains the remarkable self-healing capability of rubber at ambient temperature without any external stimulus, while a high covalent cross-linking density improves the mechanical strength and induces shape memory behavior, but effective self-healing needs to be triggered at high temperature. This strategy might open a promising pathway to fabricate intelligent multifunctional polymers with versatile functions.
Co-reporter:Heng Shen, Chunting Duan, Jing Guo, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 32) pp:NaN16669-16669
Publication Date(Web):2015/07/09
DOI:10.1039/C5TA04188K
An environmentally friendly and facile approach was developed to synthesize boron nitride nanosheet/Ag nanoparticle hybrids (BNNS/Ag) in aqueous solution at room temperature without additional reductants. BNNSs were modified with a thin layer of tannic acid–ferric ion (TA–Fe) complex. Silver nanoparticles with a uniform diameter of approximately 7 nm were in situ formed on the surface of the modified BNNSs due to the strong reducibility of TA. The resultant nanohybrids showed excellent catalytic activity in reduction of 4-nitrophenol. BNNS/Au and BNNS/Pd nanohybrids can also be fabricated by this means, implying its extensive promise in catalytic, bio-medical and sensing fields.
Co-reporter:Yi Hou, Zhen Wang, Jing Guo, Heng Shen, Huan Zhang, Ning Zhao, Yiping Zhao, Li Chen, Songmiao Liang, Yan Jin and Jian Xu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 46) pp:NaN23260-23260
Publication Date(Web):2015/10/06
DOI:10.1039/C5TA05612H
Utilizing superhydrophobic porous materials in oil/water separation has attracted increasing research interest, however, most of these materials are usually complicated to fabricate or easily lose their functions in harsh circumstances. In this study, dispersion of poly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS) micro–nano aggregations in acetone/water was facially prepared via a simple phase separation method. The aggregations can be easily coated on the skeletons of various 2D and 3D porous substrates, endowing the porous materials with superhydrophobicity. The prepared superhydrophobic materials show excellent resistance to chemical erosion, mechanical abrasion, and high temperature (up to 400 °C). This robust superhydrophobicity promises application of the resultant porous materials in harsh environments, and examples of using these superhydrophobic porous materials to separate oil/water mixtures have been demonstrated. This simple and universal method is suitable for the large-scale preparation of porous materials with robust superhydrophobicity.
Co-reporter:Chao Cai, Xiaoli Yang, Zhen Wang, Haixia Dong, Hongwei Ma, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 17) pp:NaN4259-4259
Publication Date(Web):2015/03/30
DOI:10.1039/C5TC00357A
This paper demonstrates a facile and effective improvement of abrasion resistance of silica nanoparticle (NP) based anti-reflective coatings via capillary condensation of 3-aminopropyl triethoxysilane (APTES). The quartz crystal microbalance (QCM) is used to test the abrasion resistance property. The versatility of this developed method is further illustrated by the successful application to the poor heat-resistant polymer substrates.
Co-reporter:Xiaoli Yang, Ning Zhao, Qingzhu Zhou, Chao Cai, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 20) pp:NaN3366-3366
Publication Date(Web):2013/03/26
DOI:10.1039/C3TC30324A
This paper describes a straightforward method to precisely prepare monodisperse ZrO2@SiO2 core–shell nanoparticles (CSNs) by sol–gel polymerization of TEOS in the presence of ZrO2 cores without additional capping agents. We studied the morphology and composition of CSNs by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). It has been found that the citric acid groups adsorbed onto the ZrO2 surface during the preparation of ZrO2 as well as the slow hydrolysis and condensation of TEOS in isopropanol are crucial for the selective growth of silica on the surface of ZrO2 cores. The thickness of the silica shell can be facilely controlled from about 4 to 30 nm by varying the concentration of TEOS, with the refractive indices of the prepared CSNs tuned accordingly from about 1.2 to 1.9. The coated silica shell, which can be well dispersed in solvents such as methanol and ethanol, can improve the dispersibility of pure ZrO2 nanoparticles which can only be dispersed in water. Moreover, the formation of the silica shell improved the chemical reactivity of pure ZrO2 nanoparticles. After modifying with methyltriethoxysilane (MTES), the CSNs can be well dispersed in various organic solvents, such as dimethylbenzene, chloroform and isoamyl alcohol, which may find applications in optically transparent resins with controllable refractive index or organic silicon packaging materials with high refractive index for LED and so on. Additionally, other silane coupling agents can also be applied to modify the surface chemical properties of CSNs, which may provide more potential applications.
Co-reporter:Haosen Fan, Hao Wang, Ning Zhao, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 6) pp:NaN2780-2780
Publication Date(Web):2011/12/15
DOI:10.1039/C1JM14311E
A facile method was successfully developed for the preparation of a hierarchical nanocomposite of vertical polyaniline (PANI) nanorods aligned on the surface of functional multiwalled carbon nanotubes (FMWNTs) by in situ polymerization of PANI on the surface of FMWNTs. The formation mechanism was illustrated according to the morphological evolution of PANI-FMWNTs nanocomposite at different polymerization times. The hierarchical nanocomposite possessed higher special capacitance and better stability than each individual component as supercapacitor electrode materials due to the synergistic effect of both components, as well as to the special hierarchical structure, which not only increases the specific surface area of the nanocomposite but also facilitates the penetration of electrolyte ions. This research gives a better insight into the preparation of functional hybrid nanocomposites by combining different dimensional nanomaterials.
Co-reporter:Yuhua Long, Junjie Wu, Hao Wang, Xiaoli Zhang, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2011 - vol. 21(Issue 13) pp:NaN4881-4881
Publication Date(Web):2011/02/18
DOI:10.1039/C0JM03838E
Here we demonstrate a new route to achieve the sintering of silver nanoparticles (Ag NPs) at room temperature. The as-prepared Ag NPs coalesced when they were immersed in electrolyte solutions, such as NaCl and MgSO4. The square resistances of Ag NPs thin films decreased from tens of kiloohms to lower than 1 ohm after treatment with electrolyte solutions for 10 s. Conductive Ag NPs thin films can be created on various substrates coated by polydopamine, a mussel-inspired polymer, viasilver-plating followed by treatment with electrolyte solutions at room temperature.
Co-reporter:Xiaoli Yang, Ning Zhao, Qingzhu Zhou, Zhen Wang, Chunting Duan, Chao Cai, Xiaoli Zhang and Jian Xu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:
Publication Date(Web):
DOI:10.1039/C2JM33220E
Co-reporter:Qingzhu Zhou, Haifan Xiang, Haosen Fan, Xiaoli Yang, Ning Zhao and Jian Xu
Journal of Materials Chemistry A 2011 - vol. 21(Issue 34) pp:NaN13061-13061
Publication Date(Web):2011/08/01
DOI:10.1039/C1JM11149C
A simple procedure was developed to fabricate uniform-sized hollow organic-inorganic silica spheres with a golf ball-like wrinkled surface. Two precursors, methyltrimethoxylsilane and tetraethoxysilane were hydrolyzed in solution of ammonia, and the hollow morphology was obtained by co-condensation of the two precursors, followed by self-assembly of silica and polymeric organoalkoxysilane. The composition of the two precursors and temperature were of importance for the morphological characteristics of organic-inorganic silica spheres. In addition, their size and distribution can be controlled by the dispersion manner of precursors into aqueous solution of ammonia. The framework components indicated the presence of silica and polymethylsilsesquioxane, and polymethylsilsesquioxane was distributed on the surface of the microspheres. Self-assembly of silica and polymethylsilsesquioxane based on Ostwald ripening process was proposed to explain the formation of hollow structures and golf ball-like wrinkled surface.
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