Co-reporter:Yunlong Wang, Mozhen Wang, and Xuewu Ge
Langmuir September 16, 2014 Volume 30(Issue 36) pp:10804-10808
Publication Date(Web):September 1, 2014
DOI:10.1021/la502866h
Three-dimensionally ordered macroporous (3DOM) polytetrafluoroethylene (PTFE) has hardly been prepared due to the poor solubility in most of solvents and high melting temperature of PTFE raw material. In this work, monodispersed polystyrene (PS) microspheres and PTFE latex particles were controlled to simultaneously deposit from water. After the deposits were calcinated at 400 °C, a self-supported superhydrophobic 3DOM PTFE film with a static water contact angle of 154° was successfully fabricated. The pore size can be tunable from 1.5 to 3 μm, depending on the size of PS microspheres. The prepared 3DOM PTFE film were used as micromolds and microreactors to prepare poly(methyl methacrylate) (PMMA) particles and TiO2 macroporous material, respectively. This work provides a facile method to fabricate 3DOM PTFE materials.
Co-reporter:Lan-Lan Li, Ru-Yi Jiang, Jin-Xing Chen, Mo-Zhen Wang, Xue-Wu Ge
Chinese Chemical Letters 2017 Volume 28, Issue 4(Volume 28, Issue 4) pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.cclet.2016.12.025
Self-healable polyacrylamide-based hydrogels were prepared at room temperature via a one-step emulsion copolymerization of acrylamide (AM), dodecyl 2-methacrylate (DM), and 5-acetylaminopentyl acrylate (AAPA) using sodium dodecyl sulfonate (SDS) as the emulsifier and ammonium persulfate (APS) as the initiator. The produced linear multi-block copolymer chains are composed of randomly-linked hydrophilic polyacrylamide segments (PAM) and hydrophobic segments constituted by DM and AAPA units (P(DM-co-AAPA)). The P(DM-co-AAPA) segments will self-aggregate into hydrophobic microdomains during the polymerization process driven by the hydrophobic interactions, and finally separate from water phase, acting as the crosslinks and leading to the formation of strong hydrogels with a storage modulus as high as 400 Pa. These hydrophobic microdomains will be dissolved in water when the temperature increases to 70 °C, resulting in a temperature-responsive reversible sol-gel transition of the prepared hydrogels. Furthermore, the prepared hydrogels have excellent self-healing ability. The broken hydrogels can be automatically healed into a body with a same strength within 2-min’s contact. This work provides a new simple way to prepare reversible physical crosslinked hydrogel with high strength and self-healing efficiency.Download high-res image (89KB)Download full-size imageThe temperature-responsive hydrogel with excellent self-healing ability was one-step synthesized by the emulsion copolymerization of acrylamide, dodecyl 2-methacrylate, and 5-acetylaminopentyl acrylate.
Co-reporter:Lanlan Li;Ruyi Jiang;Jinxing Chen;Mozhen Wang
RSC Advances (2011-Present) 2017 vol. 7(Issue 3) pp:1513-1519
Publication Date(Web):2017/01/04
DOI:10.1039/C6RA25929D
Excellent mechanical strength is critical for polymer hydrogels to be successfully applied in the field of mechanical devices and tissue engineering scaffolds. Herein, novel nanoparticle-reinforced polyacrylamide-based hydrogel with high mechanical strength was designed and successfully prepared in this work through the RAFT polymerization of acrylamide (AM) and ethylene glycol dimethacrylate (EGDMA) in the presence of particulate macro-RAFT agents in water. Amphiphilic poly(acrylic acid)-b-polystyrene (PAA-b-PS) copolymer was first synthesized via RAFT copolymerization in methanol. Then the vesicles of about 200 nm in size and decorated with RAFT groups were formed by the self-assembly of PAA-b-PS copolymers during the water dialysis, which can be considered as particulate macro-RAFT agents. After the addition and the polymerization of EGDMA and AM monomers in order, hydrogel filled with uniformly distributed PAA-b-PS nanoparticles was in situ formed, showing an extraordinary compression strength and tensile strength up to 7.0 MPa and 2.0 MPa, respectively, as well as an excellent fatigue resistance under loading–unloading. The self-reinforcement effect of the PAA-b-PS nanoparticles should be related to the strong interaction originating from the chemical and hydrogen bonds between the particulate macro-RAFT agents and polyacrylamide chains. This work provides not only a novel method for macro-RAFT agents, but also opens a new feasible strategy to prepare high-performance hydrogels reinforced by polymeric nanoparticles.
Co-reporter:Lanlan Li;Ruyi Jiang;Jinxing Chen;Mozhen Wang
RSC Advances (2011-Present) 2017 vol. 7(Issue 3) pp:1513-1519
Publication Date(Web):2017/01/04
DOI:10.1039/C6RA25929D
Excellent mechanical strength is critical for polymer hydrogels to be successfully applied in the field of mechanical devices and tissue engineering scaffolds. Herein, novel nanoparticle-reinforced polyacrylamide-based hydrogel with high mechanical strength was designed and successfully prepared in this work through the RAFT polymerization of acrylamide (AM) and ethylene glycol dimethacrylate (EGDMA) in the presence of particulate macro-RAFT agents in water. Amphiphilic poly(acrylic acid)-b-polystyrene (PAA-b-PS) copolymer was first synthesized via RAFT copolymerization in methanol. Then the vesicles of about 200 nm in size and decorated with RAFT groups were formed by the self-assembly of PAA-b-PS copolymers during the water dialysis, which can be considered as particulate macro-RAFT agents. After the addition and the polymerization of EGDMA and AM monomers in order, hydrogel filled with uniformly distributed PAA-b-PS nanoparticles was in situ formed, showing an extraordinary compression strength and tensile strength up to 7.0 MPa and 2.0 MPa, respectively, as well as an excellent fatigue resistance under loading–unloading. The self-reinforcement effect of the PAA-b-PS nanoparticles should be related to the strong interaction originating from the chemical and hydrogen bonds between the particulate macro-RAFT agents and polyacrylamide chains. This work provides not only a novel method for macro-RAFT agents, but also opens a new feasible strategy to prepare high-performance hydrogels reinforced by polymeric nanoparticles.
Co-reporter:Yunyun Xie, Wenxiu Yang, Mozhen Wang, Xuewu Ge
Chemical Engineering Journal 2017 Volume 323(Volume 323) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.cej.2017.04.035
•N-doped hierarchical porous carbon (FNC) microspheres were fabricated.•The FNC microspheres with a surface area of 554.5 m2/g have micro- and macro-pores.•The FNC microspheres can be stably dispersed in water due to the N-doping.•The FNC microspheres have an excellent adsorption ability for RhB and can be reused.The creation of high surface area and effective active sites is the key problem for the synthesis of high-performance porous carbon materials. In this work, polyacrylonitrile-coated fibrous silica (F-SiO2@PAN) microspheres were prepared by in situ polymerization of acrylonitrile on fibrous mesoporous silica microspheres induced by γ-ray radiation. After F-SiO2@PAN microspheres were carbonized and etched with hydrofluoric acid, uniform fibrous N-doped porous carbon (FNC) microspheres with an average size of 286 nm and a molar ratio of C/N of 5.2 were successfully prepared. As revealed by TEM, SEM, and N2 adsorption-desorption isotherms analysis, FNC microspheres have a hierarchal micro-macroporous structure with a particular high surface area of 554.5 m2/g. The FNC microspheres also exhibit a good water dispersibility and an excellent adsorption ability to rhodamine B in water. The equilibrium adsorption capacity of FNC microspheres could reach 95.4 mg/g, which is 1.6 times as that of the primary silica template microspheres. The adsorption kinetics and thermodynamics of FNC microspheres are in accord with the pseudo-second-order kinetic equation and Freundlich isotherm model, respectively. This work provides a facile synthesis method for novel N-doped hierarchical micro-macroporous carbon microsphere as a potential high-performance adsorbent material.Download high-res image (103KB)Download full-size image
Co-reporter:Qiang Zhang, Jinxing Chen, Yunyun Xie, Mozhen Wang, Xuewu Ge
Applied Surface Science 2016 Volume 368() pp:332-340
Publication Date(Web):15 April 2016
DOI:10.1016/j.apsusc.2016.01.272
Highlights
- •
PVP molecular chains will induce the assembly of the primary Bi2WO6 nanosheets.
- •
The assembly of primary Bi2WO6 nanosheets forms various 3D topological structure.
- •
Sheet-like, flower-like, red-blood-cell-like and square-pillar-like Bi2WO6 were formed.
- •
Bi2WO6 formed at low concentration or molecular weight of PVP has better activity.
Co-reporter:Lizhao Xie, Guowei Duan, Weikang Wang, Mozhen Wang, Qichao Wu, Xiao Zhou, and Xuewu Ge
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 29) pp:8123-8132
Publication Date(Web):July 7, 2016
DOI:10.1021/acs.iecr.6b01935
The surface modification of graphene oxide (GO) determines the interactions between GO and polymers, which possibly produces a significant impact on the mechanical properties of polymer. Here, GO was first modified with poly(glycidyl methacrylate) (PGMA) and triethylenetetramine (TTA) through γ-ray radiation. Then, a tiny small amount (0.04%) of the prepared modified GO was filled with a PET/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (PET/ST2000) blend. The morphological analyses on these filled PET blends confirmed that the surface chemical structure of GO had a crucial impact on the mechanical property of the blend. The chemical bonding between GO and ST2000 was more efficient in improving the dispersibility of GO and the compatibility between PET and ST2000, leading to a 2.5-fold increase in the impact strength, along with a slight increase in tensile strength. However, the addition of reduced GO lacking polar groups caused fatal damage in the mechanical property of the blend.
Co-reporter:Jie Wang, Fuxing Lin, Jinxing Chen, Mozhen Wang and Xuewu Ge
Journal of Materials Chemistry A 2015 vol. 3(Issue 47) pp:9186-9193
Publication Date(Web):04 Nov 2015
DOI:10.1039/C5TB01314C
The combination of NIR photothermal therapy and chemotherapy is considered as the promising technique for future cancer therapy. The key point of this technique is the design and synthesis of photothermal agents with high-efficiency photothermal effects and high chemical drug loading capacity. Herein, submicron-sized raspberry-like hollow-structured polypyrrole microspheres (H-PPy) were facilely prepared through in situ polymerization of pyrrole on monodispersed polystyrene (PS) template microspheres with a diameter of 220 nm, followed by the chemical etching of PS templates. The prepared H-PPy microspheres show rapid and remarkable photothermal effects in water under NIR laser irradiation (808 nm) only for 5 min. Further, a model small molecular drug, (S)-(+)-camptothecin (CPT), was loaded into the void core by a simple dispersion–permeation process through the micro-pores on the raspberry-like PPy shell, with a loading capacity of 0.14 mg/(mg H-PPy). The MTT assay and the in vitro NIR-laser triggered release behavior indicated that pure H-PPy microspheres have good biosafety, but the release of loaded CPT into H-PPy microspheres can be achieved with remarkable spatial/temporal resolution after NIR laser irradiation, which results in excellent synergistic effect of photothermal and chemical ablation on HeLa cells, as proved by fluorescence microscopy. This work provides convenient synthesis of a promising cancer therapy agent with high drug-loading capacity and efficient NIR light photothermal effects, which can perfectly achieve the synergistic NIR photothermal therapy and chemotherapy of PPy microspheres.
Co-reporter:Lechen Chen, Lizhao Xie, Mozhen Wang and Xuewu Ge
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:2991-2998
Publication Date(Web):08 Dec 2014
DOI:10.1039/C4TA05898D
Three-dimensional inverse opal SnO2/graphene (IO-SnO2/graphene) microspheres with a size of several tens of microns are first prepared by a well-designed two-step calcination of polystyrene (PS) colloidal crystal template balls infiltrated with the sol precursors of SnO2 and graphene oxide. The polystyrene colloidal crystal template balls are formed by the self-assembly of monodispersed PS microspheres confined in water droplets of an inverse emulsion induced by the slow evaporation of water. Characterization with scanning electronic microscopy, Raman spectra, X-ray diffraction and X-ray photoelectron spectroscopy proved the ordered macroporous inverse opal composed of crystalline SnO2 and in situ reduced GO during the calcination. The pore size depends on the PS microspheres. The UV-vis diffusive reflectance spectra show that the light absorption edge of the prepared IO-SnO2/graphene microspheres can shift more than 400 nm. The photoluminescence spectra indicates that the IO structure and the introduction of rGO make the charge carriers transfer fast and retard the hole/electron recombination in the IO-SnO2/graphene microspheres so that their photocatalytic performance on the UV photolysis of methyl orange is considerably better than that of commercial SnO2 nanoparticles. However, the photocatalytic performance also depends on the content of GO. The addition of 0.06 wt% of GO achieves the best photocatalytic effect. Excessive GO will result in a diminished catalytic activity. This work provides a way to fabricate a new morphological SnO2 based materials with enhanced photocatalytic activity, which helps in the exploration of new photocatalysts with high performance.
Co-reporter:Lizhao Xie, Yunyun Xie, Qianghua Wu, Mozhen Wang, Qichao Wu, Xiao Zhou, and Xuewu Ge
Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 17) pp:4748-4755
Publication Date(Web):April 17, 2015
DOI:10.1021/acs.iecr.5b00091
The preparation of supertoughening poly(ethylene terephthalate) (PET) blends has always been a practical and valuable task. In our work, PET resins grafted with poly(acrylic acid) (PAA), termed as PET-g-PAA, were first prepared through γ-ray radiation induced graft polymerization and blended in a partially miscible PET/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (ST2000) system as the compatibilizer. The impact strength of the PET blends achieves the maximum at a 6 wt % of PET-g-PAA, but without the loss of tensile strength. Furthermore, much less of ST2000 is needed for the blends to possess high impact strength at the existence of PET-g-PAA. The SEM morphological analysis of the impact-fracture surface implies a good interfacial adhesion between ST2000 and PET matrix, which should be ascribed to the effective compatibilization by the in situ formed PET-g-PAA/ST2000 graft copolymer through the reaction between the —COOH groups and epoxy groups on ST2000.
Co-reporter:Sheng Cheng, Bin Zheng, Mozhen Wang, Michael Hon-Wah Lam, Xuewu Ge
Analytical Biochemistry 2014 Volume 446() pp:69-75
Publication Date(Web):1 February 2014
DOI:10.1016/j.ab.2013.10.021
Abstract
A strand displacement reaction (SDR) system that runs solely on oligonucleotides has been developed for the amplification detection of adenosine triphosphate (ATP). It involves a target-induced SDR and an entropy-driven catalytic cycle of two SDRs with five oligonucleotides, denoted as substrate, fuel, catalyst, C-1, and C-2. Catalyst, released from the ATP aptamer–catalyst duplex by ATP molecule, catalyzes the SDRs to finally form the substrate–fuel duplex. All of the intermediates in the catalytic SDR processes have been identified by polyacrylamide gel electrophoresis (PAGE) analysis. The introduction of ATP into the SDR system will induce the ATP aptamer to form G-quadruplex conformation so as to release catalyst and trigger the SDR cycle. When the substrate and C-2 oligonucleotides were labeled with a carboxyfluorescein (FAM) fluorophore and a 4-([4-(dimethylamino)phenyl]azo)benzoic acid (DABCYL) quencher, this SDR catalytic system exhibited a “turn-on” response for ATP. The condition for detecting ATP, such as Mg2+ concentration, has been optimized to afford a detection limit of 20 nM. This work provides an enzyme-free biosensing strategy and has potential application in aptamer-based biosensing.
Co-reporter:Dong Zhao, Mozhen Wang, Yongfei Xu, Zhicheng Zhang, Xuewu Ge
Surface and Coatings Technology 2014 Volume 238() pp:15-26
Publication Date(Web):15 January 2014
DOI:10.1016/j.surfcoat.2013.10.031
•BTA can be encapsulated in raspberry-like hollow polymeric microspheres.•The release of BTA can be triggered by the change of pH.•The BTA-encapsulated raspberry-like hollow microspheres can be embedded into WPU film.•The composite WPU film exhibits good anti-corrosive property.This work presents a synthesis of submicron-sized raspberry-like hollow microspheres loaded with corrosion inhibitor (1H-benzotriazole (BTA)) through a multi-stage emulsion polymerization. The combination of hierarchical raspberry-like surface structure and loading of BTA makes the prepared microspheres have good corrosion resistance. When BTA-loaded raspberry-like hollow microspheres are embedded in a water-borne polyurethane film, the obtained composite film can protect the copper from corrosion both in acidic and alkaline corrosive solutions.
Co-reporter:Sheng Cheng, Bin Zheng, Mozhen Wang, Xuewu Ge, Qing Zhao, Wei Liu, Michael Hon-Wah Lam
Biosensors and Bioelectronics 2014 Volume 53() pp:479-485
Publication Date(Web):15 March 2014
DOI:10.1016/j.bios.2013.10.016
•The adsorption of DNAs in G-quadruplex solutions onto gold nanoparticles was observed.•The adsorption behavior was investigated in three widely used guanine-rich sequences.•ICP-AES was used to discover the occurrence of the unfolding of G-quadruplexes.•The potential unfolding by gold nanoparticles has adverse effect on the biosensing system.The adsorption of DNAs in G-quadruplex solution onto 13 nm gold nanoparticles (AuNPs) was studied through monitoring of the localized surface plasmon resonance (LSPR) absorbance of 13 nm AuNPs at 520 and 650 nm (A650/A520) in the solutions of three widely studied guanine-rich sequences, TBA(5′-GGTTGGTGTGGTTGG-3′), PW17(5′-GGGTAGGGCGGGTTGGG-3′), and PSO (5′-GGGTTAGGGTTAGGGTTAGGG-3′). It was found that the degree of adsorption of DNAs in Pb2+ stabilized G-quadruplex (G-Pb2+) solutions is up to 93% after more than 5 h of incubation. Furthermore, the lead concentrations in the solutions containing G-quadruplex and AuNP were analyzed by an inductively coupled plasma atomic emission spectrometer. The results showed that Pb2+ had been released from the G-quadruplexes, which means the G-quadruplexes may be unfolded in the presence of AuNP. This interaction between G-quadruplexes and AuNP demonstrated that long time incubation between DNAs and AuNPs would possibly make it unable to distinguish G-quadruplex from ssDNA. Thus, a biosensing system consisting of PW17 and AuNPs was developed to detect Pb2+. It was found that the LSPR responses at A650/A520 were sensitive to [Pb2+]. However, the sensitivity of the system was interfered by the potential unfolding of PW17-Pb2+ in the presence of AuNPs. This unexpected adverse effect of AuNPs on DNA-based biosensors should be taken into consideration in the future development of biosensing systems that are based on ssDNA aptamers and unmodified AuNPs.
Co-reporter:Yusong Wang, Lianghua Xu, Mozhen Wang, Wenmin Pang, and Xuewu Ge
Macromolecules 2014 Volume 47(Issue 12) pp:3901-3908
Publication Date(Web):June 3, 2014
DOI:10.1021/ma500727n
Four kinds of 13C-labeled polyacrylonitrile (PAN) samples were prepared respectively by solution polymerization of acrylonitrile (AN) with selective 13C labeling of different molecular sites. The composition and structure of the residues from the thermal treatment of PAN in argon at 250 and 350 °C were quantitatively analyzed in detail by one- and two-dimensional solid-state 13C nuclear magnetic resonance (ssNMR) experiments. Compared with the NMR spectrum of each labeled carbon in AN monomer unit, nine chemical structures created during the heat treatment process have been identified accurately. On this basis, four reaction routes were proposed. It is noted that the main chemical change for PAN started from a cyclization reaction at a relatively low temperature, then experienced an aromazation reaction to form a molecular chain basically composed of isolated pyridine units, instead of the commonly reported ladder structure. This work also shows that the combination of selectively 13C-labeled technique and a high spinning speed of 20 kHz in magic-angle spinning (MAS) NMR experiment could improve the detection sensitivity to nearly 2 orders of magnitude, and provide a clear ssNMR spectra with little peak overlaps, which will be helpful to discover the complex reaction mechanism in the manufacture of carbon fibers with high performance.
Co-reporter:Yunlong Wang, Mozhen Wang, and Xuewu Ge
Langmuir 2014 Volume 30(Issue 36) pp:10804-10808
Publication Date(Web):September 1, 2014
DOI:10.1021/la502866h
Three-dimensionally ordered macroporous (3DOM) polytetrafluoroethylene (PTFE) has hardly been prepared due to the poor solubility in most of solvents and high melting temperature of PTFE raw material. In this work, monodispersed polystyrene (PS) microspheres and PTFE latex particles were controlled to simultaneously deposit from water. After the deposits were calcinated at 400 °C, a self-supported superhydrophobic 3DOM PTFE film with a static water contact angle of 154° was successfully fabricated. The pore size can be tunable from 1.5 to 3 μm, depending on the size of PS microspheres. The prepared 3DOM PTFE film were used as micromolds and microreactors to prepare poly(methyl methacrylate) (PMMA) particles and TiO2 macroporous material, respectively. This work provides a facile method to fabricate 3DOM PTFE materials.
Co-reporter:Sheng Cheng, Bin Zheng, Mozhen Wang, Michael Hon-Wah Lam, Xuewu Ge
Talanta 2013 Volume 115() pp:506-511
Publication Date(Web):15 October 2013
DOI:10.1016/j.talanta.2013.05.065
•A double-functionalized gold nanoparticle-split aptamer system has been developed.•The LSPR response of this system to ATP was much higher than the traditional one.•Time courses of the AuNPs assembly under various systems and conditions were studied.•This newly developed system provided a general way for design of other biosensors.A newly designed functionalization type for gold nanoparticles (AuNP) with split aptamer has been developed for the detection of adenosine triphosphate (ATP). The ATP aptamer was split into two parts with their 5′ prime or 3′ prime modified with thiol. Both the 5′ SH and 3′ SH modified strands for each split aptamer fragment were functionalized onto the same AuNP to construct double-functionalized AuNP–DNA conjugates. Thus, the split aptamer can be reassembled into intact folded structure in the presence of ATP molecule with two potential assembly types, which induces the assembly of AuNP–DNA conjugates. In this double-functionalized system, the traditional assembly type might facilitate another assembly type, which was found to give much higher LSPR change in the presence of ATP than the traditional assembly type, and improve the sensitivity for ATP detection. Time courses of the assemble processes with different assembly types, Mg2+ concentrations, and aptamer fragments densities on AuNP were followed using the absorption ratio at 650 nm and 520 nm. ATP response with this newly designed system was investigated using absorption spectra and dynamic light scattering method.
Co-reporter:Xiang Ji, Mozhen Wang, Xuewu Ge, and Huarong Liu
Langmuir 2013 Volume 29(Issue 4) pp:1010-1016
Publication Date(Web):January 2, 2013
DOI:10.1021/la304806d
In this work, an asymmetric swelling–dissolving process of original submicrometer-sized decentered sulfonated polystyrene/silica (SPS/silica) particles in a ternary mixed solvent (water/ethanol/heptane) was first reported. Actinia-like and porous snowman-like SPS/silica composite particles are fabricated through tuning the composition of the ternary mixed solvent. Actinia-like particles, with a silica core embedded in a “blooming” SPS matrix, are obtained when the composition of the mixed solvent is 5 g/5 g/0.1 g (water/ethanol/heptane). If the amount of heptane in the mixed solvent is doubled, then porous snowman-like particles are produced. The TEM and SEM images show that silica particles are exposed in these two anisotropic SPS/silica composite particles compared with the original decentered SPS/silica particles. Considering the particles morphology and the swelling and dissolving performance of SPS in different solvents, the formation of the new-shaped anisotropic SPS/silica composite particles should be attributed to an asymmetric swelling-dissolving process; that is, the swelling–dissolving rate of SPS coating around the protruding silica part is faster than the other part of the composite particles. The anisotropic swelling–dissolving property of polymer/inorganic composite particles inspires a facile way to the fabrication of new composite particles.
Co-reporter:Bingxin Li, Yongfei Xu, Mozhen Wang, and Xuewu Ge
Langmuir 2013 Volume 29(Issue 48) pp:14787-14794
Publication Date(Web):2017-2-22
DOI:10.1021/la403166q
In this work, we first reported that the phase separation can take place both inside and outside of a multihollow-structured cross-linked seed microspheres swollen by styrene monomers in water during the radiation-induced seeded emulsion polymerization. The phase separation process in these two opposite directions will determine the morphology of final latex particles. First, sulfonated cross-linked polystyrene (SCPS) seed microspheres were swollen by styrene in water. Water will permeate into the SCPS seed microspheres during the swelling process, forced by the osmotic pressure produced by the strong hydrophilicity of the sulfonic acid groups. New aqueous phases are created and stabilized by the hydrophilic −SO3H groups, resulting in a multihollow structure of swollen SCPS seed microspheres. When the polymerization of styrene is induced by 60Co γ-ray radiation, the phase separation of newly formed polystyrene phase will occur at the seed microsphere-water interface inside and/or outside of the SCPS seed microspheres through adjusting the diameter of seed microsphere, the content of cross-link agent, and the sulfonation degree of SCPS seed microspheres. As a result, SCPS latex particles with a variety of special morphologies, such as spherical multihollow, plum-like, and walnut-like latex particles were obtained. The results of this study provide not only a simple and interesting way to design and synthesize multihollow polymer latex particles with controllable surface morphologies but also a better understanding on phase separation mechanism during the swelling and polymerization of monomers in cross-linked amphiphilic polymer networks.
Co-reporter:Dezhi Xu, Mozhen Wang, Xuewu Ge, Michael Hon-Wah Lam and Xueping Ge
Journal of Materials Chemistry A 2012 vol. 22(Issue 12) pp:5784-5791
Publication Date(Web):14 Feb 2012
DOI:10.1039/C2JM15364E
We report a facile and novel strategy on the fabrication of well-defined raspberry SiO2/polystyrene (SiO2/PS) particles via radiation miniemulsion polymerization. Starting from methacryloxypropyltrimethoxysilane (MPS)-functionalized SiO2 particles (176 nm), raspberry SiO2/PS particles (257 nm) with a submicron SiO2 core decorated by nano-sized PS latex particles (58 nm) are obtained after γ-ray induced miniemulsion polymerization of styrene (St). It is found that MPS grafted density on the surface of submicron SiO2 particles, the weight ratio of St to SiO2 particles (WSt/o-SiO2), as well as the surfactant concentration will affect the morphology and wettability of the resultant SiO2/PS hybrid particles. When the well-defined raspberry SiO2/PS particles are deposited on a blank glass substrate, a dual-size roughness surface topology was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). This film has a static water contact angle as high as 151°. However, this film exhibits a large contact angle hysteresis (∼116°) and strong adhesion to water. Furthermore, this kind of superhydrophobic particulate film can be used as a “mechanical hand” for transportation of small water droplets without loss, thus it may have potential applications in industrial fields.
Co-reporter:Jianan Zhang, Xuewu Ge, Mozhen Wang, Mingyuan Wu, Jianjun Yang and Qingyun Wu
Polymer Chemistry 2012 vol. 3(Issue 8) pp:2011-2017
Publication Date(Web):24 Apr 2012
DOI:10.1039/C2PY20193C
Seed polymer/silica particles are synthesized by double in situ miniemulsion polymerization of methyl methacrylate (MMA) and hydrolysis–condensation of tetraethoxysilane (TEOS) under basic conditions simultaneously. Nanocomposite microparticles with a controlled morphology are fabricated from seed polymer/silica particles by the further miniemulsion polymerization of styrene. We have demonstrated that the seed PMMA/silica particles are cross-linked by nanosilica particles, which are dispersed homogeneously in the polymer matrix. The in situ formed silica nanoparticles acting as the cross-linking agent favor the formation of nonspherical nanocomposite microparticles with a flower-like structure. Furthermore composite microparticles of spherical morphology are obtained without γ-(trimethoxysilyl)propyl methacrylate (MPS). The addition of divinylbenzene (DVB) leads to a higher degree of cross-linking of the seed polymer particles, which favors the formation of peanut-like microparticles.
Co-reporter:Dezhi Xu;Mozhen Wang;Michael Hon-Wah Lam
Macromolecular Rapid Communications 2012 Volume 33( Issue 22) pp:1945-1951
Publication Date(Web):
DOI:10.1002/marc.201200437
Abstract
Polystyrene (PS) microspheres coated with β-cyclodextrin (β-CD) were fabricated via γ-ray-induced emulsion polymerization in a ternary system of styrene/β-CD/water (St/β-CD/water). The solid inclusion complex of St and β-CD particles formed at the St droplets–water interface can stabilize the emulsion as the surfactant. TEM and XPS results showed that β-CD remains on the surface of PS particles. The average size of the PS particles increases from 186 to 294 nm as the weight ratio of β-CD to St rises from 5% to 12.5%. The water contact angle (CA) of PS latex film is lower than 90°, and reduces with the β-CD content even to 36°. Thus, this work provides a new and one-pot strategy to surface hydrophilic modification on hydrophobic polymer particles with cyclodextrins through radiation emulsion polymerization.
Co-reporter:Dezhi Xu, Xiang Ji, Huarong Liu, Mozhen Wang, Xuewu Ge, Michael Hon-Wah Lam
Materials Letters 2012 Volume 79() pp:61-64
Publication Date(Web):15 July 2012
DOI:10.1016/j.matlet.2012.03.102
A novel strategy has been designed for the preparation of triangle polystyrene/SiO2 (PS/SiO2) hybrid particles using γ-ray radiation-induced seeded emulsion polymerization from core–shell structured PS/SiO2 seed particles. SEM results indicate that the weight ratio of monomer to seed particles (WSt/Seed) and the thickness of silica-shell coated on the core–shell PS/SiO2 seed particles are crucial for the subsequent formation of triangle hybrid particles. Moreover, the size of the protruded PS bulbs of the resultant triangle particles obviously increases with WSt/Seed from 1.25 to 5. This novel method is applicable to the preparation of anisotropic hybrid particles from polymer/inorganic core–shell particles.Highlights► Triangle particles were prepared via radiation seeded emulsion polymerization. ► Micron-sized core-shell PS/SiO2 particles were used as seeds. ► Silica-shell thickness is crucial for the formation of the triangle particles. ► This strategy is promisingly applicable to preparation of anisotropic particles.
Co-reporter:Xueping Ge;Mozhen Wang;Huarong Liu;Bin Fang
Colloid and Polymer Science 2012 Volume 290( Issue 17) pp:1749-1757
Publication Date(Web):2012 November
DOI:10.1007/s00396-012-2709-8
A new and effective process has been developed for fabrication of novel cage-like multihollow polymer particles by using sulfonated polystyrene (SP) particles as the templates, with heptane as the phase separation agent, in an ethanol/water medium. The ratio of water/ethanol and the heating temperature play important roles in the formation of these multihollow particles. It was found that the cage-like polymer particles could be obtained when the ratio of ethanol/water is 5:5 (w/w), with a temperature above 50 °C. After a detailed study, the formation mechanism was proposed based on an SP swollen (ethanol and heptane penetrating process) and phase separation process. This new method for fabricating the cage-like multihollow polymer particles has a great meaning not only on confirming the formation mechanism, but also on providing an effective way to prepare the special hollow core/porous shell polymer particles, which could have wide range of potential applications, such as catalysts, sensors, and drug release.
Co-reporter:Xiang Ji, Mozhen Wang, Dezhi Xu, Xuewu Ge, Huarong Liu, and Tao Tang
Langmuir 2012 Volume 28(Issue 13) pp:5498-5502
Publication Date(Web):March 16, 2012
DOI:10.1021/la204707u
A novel spongelike polymer material has been fabricated by γ-ray induced polymerization of methylmethacrylate (MMA) in an emulsion containing cross-linked sulfonated polystyrene (CSP) particles. Scanning electron microscopy (SEM) images reveal that the spongelike structure is made up of interlinked nanosized PMMA particles with micrometer-sized CSP-PMMA particles embedded inside. The nitrogen adsorption isotherm discloses that the spongelike material has a high specific surface area of 29 m2/g and a narrow pore size distribution of 60–120 nm. The formation mechanism is discussed in this paper, which indicates that the key steps to form the spongelike material include a Pickering emulsion stabilized by the CSP particles, followed by the swelling process of MMA into these particles. This approach offers a more convenient alternative to prepare polymeric spongelike material without any etching procedure.
Co-reporter:Jianan Zhang, Xuewu Ge, Mozhen Wang, Jianjun Yang, Qingyun Wu, Mingyuan Wu and Dandan Xu
Polymer Chemistry 2011 vol. 2(Issue 4) pp:970-974
Publication Date(Web):03 Feb 2011
DOI:10.1039/C0PY00320D
This paper presents a facile method for the preparation of silver/polystyrene (Ag/PS) composite microspheres. PS microspheres with carboxyl and nitrile groups on the surfaces were synthesized via a two-step dispersion copolymerization of styrene, itaconic acid, and acrylonitrile in ethanol–water media. Ag/PS composite microspheres were prepared successively by addition of AgNO3 aqueous solution to the dispersion, absorbing to the surfaces of functional PS microspheres, and then reduction of Ag+ ions to silver nanoparticles by aqueous hydrazine hydrate. The results showed that Ag nanoparticles with size of about 50 nm were located on the shell of PS microspheres due to the combined interactions between the carboxyl and nitrile groups of PS microspheres and the in situ formed silver nanoparticles. The as-prepared Ag/PS microspheres showed good catalytic properties.
Co-reporter:Xueping Ge;Mozhen Wang;Huarong Liu;Bin Fang;Zhi Li;Xiaojun Shi;Cunzhong Yang;Guang Li
Macromolecular Rapid Communications 2011 Volume 32( Issue 20) pp:1615-1619
Publication Date(Web):
DOI:10.1002/marc.201100337
Co-reporter:Jianan Zhang, Mozhen Wang, Xuewu Ge, Mingyuan Wu, Qingyun Wu, Jianjun Yang, Manyi Wang, Zhilai Jin, Nannan Liu
Journal of Colloid and Interface Science 2011 Volume 353(Issue 1) pp:16-21
Publication Date(Web):1 January 2011
DOI:10.1016/j.jcis.2010.09.007
This paper reports a rapid and facile method of preparing free-standing colloidal crystals from monodisperse charged polystyrene (PS) microspheres. Mixed solvents (ethanol/water) were used as the dispersion medium in the self-assembly process of colloidal crystals. By a simple “floating self-assembly” method, PS microspheres floated on the surface of liquid and self-assembled into large area of three-dimensional (3D) ordered colloidal crystals within 15 min. Then epichlorohydrin was added in as a cross-linking agent to strengthen the colloidal-crystal film. After cross-linking reactions between the microspheres, the obtained colloidal-crystal film was free-standing and could be easily transferred to other substrates. Using tetrabutyl titanate as a titania precursor, 3D porous TiO2 materials with rodlike skeletal structure were fabricated from the prepared free-standing colloidal crystal. This work provides a facile method to fabricate free-standing colloidal-crystal film, which can be used as an ideal template for the preparation of porous materials.Graphical abstractOptical photographs of colloidal multi-layers from PS microspheres of different size: (a) 140 nm, (b) 216 nm, and (c) 282 nm. (d and e) show the free-standing colloidal films prepared from 158 nm microspheres.Research highlights► Colloidal crystals are fabricated via “floating self-assembly” method within 15 min. ► Free-standing colloidal-crystal film is obtained using epichlorohydrin as cross-linking agent. ► Free-standing colloidal crystals could be used as ideal templates for 3DOM materials.
Co-reporter:Jianan Zhang, Xuewu Ge, Mozhen Wang, Jianjun Yang, Qingyun Wu, Mingyuan Wu, Nannan Liu and Zhilai Jin
Chemical Communications 2010 vol. 46(Issue 24) pp:4318-4320
Publication Date(Web):11 May 2010
DOI:10.1039/C002844D
Hybrid hollow microspheres are fabricated successfully from double emulsions stabilized by single-component amphiphilic silica nanoparticles, which were formed and partially modified in situ at the interface of water-in-oil emulsions.
Co-reporter:Jianan Zhang;Nannan Liu;Mozhen Wang;Mingyuan Wu;Jianjun Yang;Qingyun Wu;Zhilai Jin
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 14) pp:3128-3134
Publication Date(Web):
DOI:10.1002/pola.24094
Abstract
Polymer/SiO2 nanocomposite microspheres were prepared by double in situ miniemulsion polymerization in the presence of methyl methacrylate, butyl acrylate, γ-methacryloxy(propyl) trimethoxysilane, and tetraethoxysilane (TEOS). By taking full advantage of phase separation between the growing polymer particles and TEOS, inorganic/polymer microspheres were fabricated successfully in a one-step process with the formation of SiO2 particles and the polymerization of organic monomers taking place simultaneously. The morphology of nanocomposite microspheres and the microstructure, mechanical properties, thermal properties, and optical properties of the nanocomposite films were characterized and discussed. The results showed that hybrid microspheres had a raspberry-like structure with silica nanoparticles on the shells of polymer. The silica particles of about 20 nm were highly dispersed within the nanocomposite films without aggregations. The transmittance of nanocomposite film was comparable to that of the copolymer film at around 70–80% from 400 to 800 nm. The mechanical properties and the fire-retardant behavior of the polymer matrix were improved by the incorporation of silica nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3128–3134, 2010
Co-reporter:Xueping Ge, Mozhen Wang, Hua Wang, Qiang Yuan, Xuewu Ge, Huarong Liu and Tao Tang
Langmuir 2010 Volume 26(Issue 3) pp:1635-1641
Publication Date(Web):September 24, 2009
DOI:10.1021/la902493r
Novel walnut-like multihollow polymer particles were first prepared by γ-ray radiation emulsion polymerization using cross-linked and sulfonated polystyrene spheres (CSPs) as the template. The formation process was studied in detail, and the morphology of walnut-like multihollow polystyrene particles could be controlled by the content of cross-linking agent, sulfonation time of CSP particles, and the weight ratio of monomer/CSP. In addition, an application of walnut multihollow polymer particles on bonding Ag nanoparticles onto the surface was achieved, which could be extended to other noble metal nanoparticles and could have a wide range of potential applications, such as catalysts, sensors, solar cells, and photonic crystals.
Co-reporter:Xueping Ge, Mozhen Wang, Qiang Yuan, Hua Wang and Xuewu Ge
Chemical Communications 2009 (Issue 19) pp:2765-2767
Publication Date(Web):27 Mar 2009
DOI:10.1039/B901094G
Novel anisotropic hybrid particles with various morphologies have been synthesized by radiation miniemulsion polymerization for the first time.
Co-reporter:Xueping Ge;Mozhen Wang;Xiang Ji;Huarong Liu
Colloid and Polymer Science 2009 Volume 287( Issue 7) pp:819-827
Publication Date(Web):2009 July
DOI:10.1007/s00396-009-2036-x
The effects of the concentration of polyoxyethylene octylphenyl ether (OP-10) as a nonionic surfactant and the molecular weight of polymers (polystyrene (PS) and poly(methyl methacrylate) (PMMA)) on the morphology of anisotropic PS/PMMA composite particles were investigated. In the case of polymers with lower molecular weight (Mw ≈ 6.0 × 104 g/mol), the PS/PMMA composite particles have dimple, via acorn, to hemispherical shapes along with the increase of the OP-10 concentration. On the other hand, when the polymers have higher molecular weight (Mw ≈ 3.3 × 105 g/mol), the morphology of PS/PMMA composite particles changed from dimple, via hemispherical, to snowman-like structure while the concentration of OP-10 was increased. Furthermore, thermodynamic analysis was first simply made by spreading coefficients, and the results indicated that both the concentration of OP-10 aqueous solution and the molecular weight of polymers were very important to the final morphology of anisotropic composite particles.
Co-reporter:Qiang Yuan, Libin Yang, Mozhen Wang, Hua Wang, Xueping Ge and Xuewu Ge
Langmuir 2009 Volume 25(Issue 5) pp:2729-2735
Publication Date(Web):February 6, 2009
DOI:10.1021/la803724r
Multihollow poly(methyl methacrylate) (PMMA) particles were successfully fabricated simply by γ-ray radiating emulsions consisting of MMA monomers, sulfonated polystyrene (SP) particles, and water. The mechanism on the formation of the holes was studied in detail. It was found that there were two routes to achieve two different multihollow structures dependent on the initial location of SP particles before emulsification. If SP particles first located in the water phase, cage-like hollow PMMA particles were obtained through the formation of a Pickering emulsion. Otherwise, if SP particles first located in the oil (MMA) phase, a different multihollow structure would be produced via the formation of a multiple emulsion. This work provides a simple method to fabricate two different structured multihollow particles using the same conditions.
Co-reporter:H.F. Xiang, X. Zhang, Q.Y. Jin, C.P. Zhang, C.H. Chen, X.W. Ge
Journal of Power Sources 2008 Volume 183(Issue 1) pp:355-360
Publication Date(Web):15 August 2008
DOI:10.1016/j.jpowsour.2008.04.091
The effect of the capacity matchup between cathode and anode in the LiNi0.5Mn1.5O4/Li4Ti5O12 cell system on cycling property, choice of electrolyte, high voltage and overcharge tolerances was investigated by comparing the cells with Li4Ti5O12 limiting capacity with the cells with LiNi0.5Mn1.5O4 limiting capacity. The former exhibits better cycling performance and less limitation of electrolyte choice than the latter. Furthermore, the Li4Ti5O12-limited cell exhibits better tolerance to high voltage and overcharge than the LiNi0.5Mn1.5O4-limited cell, owing to taking advantage of the extra capacity of Li4Ti5O12 below 1 V. It is thus recommended that the LiNi0.5Mn1.5O4/Li4Ti5O12 cell whose capacity is limited by Li4Ti5O12 anode should be used to extend the application of the state-of-the-art lithium-ion batteries.
Co-reporter:H.F. Xiang, Q.Y. Jin, R. Wang, C.H. Chen, X.W. Ge
Journal of Power Sources 2008 Volume 179(Issue 1) pp:351-356
Publication Date(Web):15 April 2008
DOI:10.1016/j.jpowsour.2007.12.089
The compatibility between dimethyl methylphosphonate (DMMP)-based electrolyte of 1 M LiPF6/EC + DMC + DMMP (1:1:2 wt.) and spinel materials Li4Ti5O12 and LiNi0.5Mn1.5O4 was reviewed, respectively. The cell performance and impedance of 3-V LiNi0.5Mn1.5O4/Li4Ti5O12 lithium-ion cell with the DMMP-based nonflammable electrolyte was compared with the baseline electrolyte of 1 M LiPF6/EC + DMC (1:1 wt.). The nonflammable DMMP-based electrolyte exhibited good compatibility with spinel Li4Ti5O12 anode and high-voltage LiNi0.5Mn1.5O4 cathode, and acceptable cycling performance in the LiNi0.5Mn1.5O4/Li4Ti5O12 full-cell, except for the higher impedance than that in the baseline electrolyte. All of the results disclosed that the 3 V LiNi0.5Mn1.5O4/Li4Ti5O12 lithium-ion battery was a promising choice for the nonflammable DMMP-based electrolyte.
Co-reporter:Linyong Song, Yuanhua Cong, Mozhen Wang, Xuewu Ge, Zhicheng Zhang
Journal of Colloid and Interface Science 2008 Volume 322(Issue 1) pp:231-236
Publication Date(Web):1 June 2008
DOI:10.1016/j.jcis.2008.01.057
Emulsion polymerization of styrene was carried out using two kinds of alkyl polyoxyethylene ether sulfosuccinates as surfactant: disodium cetyl polyoxyethylene (25) ether sulfosuccinate (CPS) and octyl-phenol polyoxyethylene (10) ether sulfosuccinate (OPS). In experiments, the incorporation of CPS or OPS inside styrene droplets and polystyrene particles was clearly observed. Based on this phenomenon, multihollow polymer spheres are prepared in a one-step reaction and this strongly supports the proposed incorporation mechanism. CPS is more effective than OPS during the preparation of multiporous spheres. This difference between the two surfactants mainly contributes to the difference of the length of the EO (polyoxyethylene) group, which can determine the affinity among surfactant, styrene, and water molecules.By the incorporation of disodium cetyl polyoxyethylene (25) ether sulfosuccinate inside styrene droplets, multihollow polymer spheres were prepared in a one-step reaction and this strongly supports the proposed incorporation mechanism.
Co-reporter:Libin Yang, Xuewu Ge, Mozhen Wang, Linyong Song, Xiaodong He
Materials Letters 2008 Volume 62(Issue 3) pp:429-431
Publication Date(Web):15 February 2008
DOI:10.1016/j.matlet.2007.05.057
In the present work, we have developed a novel route to wrap inorganic nanoparticles in polymer hollow spheres, which includes self-assembly polystyrene (PS) latex particles at the aqueous/oil interface, sintering and γ-ray radiation reduction. The Ag/PS composite microspheres were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FESEM). The advantage of this method is that the PS shell thickness, permeability, the size of composite spheres, and the quantity of the encapsulated Ag nanoparticles can be easily adjusted, which gives the product a brilliant prospect in the field of catalysis.
Co-reporter:H.F. Xiang, Q.Y. Jin, C.H. Chen, X.W. Ge, S. Guo, J.H. Sun
Journal of Power Sources 2007 Volume 174(Issue 1) pp:335-341
Publication Date(Web):22 November 2007
DOI:10.1016/j.jpowsour.2007.09.025
Dimethyl methylphosphonate (DMMP) was used as a cosolvent to reformulate the nonflammable electrolyte of 1 M LiPF6/EC + DEC + DMMP (1:1:2 wt.) in order to improve the safety characteristics of lithium-ion batteries. The flammability, cell performance, low-temperature performance and thermal stability of the DMMP-based electrolyte were compared with the electrolyte of 1 M LiPF6/EC + DEC (1:1 wt.). The nonflammable electrolyte exhibits good oxidation stability at the LiCoO2 cathode and poor reduction stability at the mesocarbon microbead (MCMB) and surface-modified graphite (SMG) anodes. The addition of vinyl ethylene carbonate (VEC) to the DMMP-based electrolyte provided a significant improvement in the reduction stability at the carbonaceous electrodes. Furthermore, it was found that the addition of DMMP resulted in optimized low-temperature performance and varied thermal stability of the electrolytes. All of the results indicated the novel DMMP-based electrolyte is a promising nonflammable electrolyte to resolve the safety concerns of lithium-ion batteries.
Co-reporter:Hua Wang;Linyong Song;Huarong Liu
Colloid and Polymer Science 2007 Volume 285( Issue 10) pp:1093-1100
Publication Date(Web):2007 July
DOI:10.1007/s00396-007-1659-z
Polyurethane (PU) was successfully synthesized and used as costabilizer in the miniemulsion polymerization of styrene (St) initiated by 60Co γ-ray radiation at room temperature. Only 2 wt% PU based on the monomer was enough to prepare a stable miniemulsion with a shelf life of more than 12 months. Preservation of original particle size and distribution throughout the polymerization observed from dynamic light scattering measurements indicates the predominance of monomer droplet nucleation. Kinetic analysis shows that there is no constant rate stage, which also suggests a droplet nucleation mechanism. Polystyrene (PS) nanoparticles with relatively small diameters (40–70 nm) and narrow size distribution could be easily prepared. The effects of surfactant, costabilizer, and absorbed dose rate on the miniemulsion polymerization were discussed.
Co-reporter:Linyong Song;Mozhen Wang;Zhicheng Zhang;Shicheng Li
Journal of Polymer Science Part A: Polymer Chemistry 2006 Volume 44(Issue 8) pp:2533-2541
Publication Date(Web):2 MAR 2006
DOI:10.1002/pola.21322
We herein report a facile, convenient, and economical method to prepare hollow polymer spheres (HSs). By virtue of the phase transformation of nonionic surfactant at its cloud point, hollow spheres of polystyrene were prepared from vesicle templates formed by potassium oleate (KO) and alkyl-phenol polyoxyethylene (n) ether (n = 10, OP) at 70–80 °C. The morphologies of the HSs were characterized by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The diameter of the HSs varies from 200 to 800 nm, and the shell thickness is uniformly c.a. 30–50 nm. The weight ratio of monomer/surfactant was as high as 7/1. The microstructure of the HSs was very stable and remained unchanged after drying or resuspension in water. The mechanism of the formation of HSs was explained on the theory of vesicles. Furthermore, the factors affecting the formation of the hollow structure were discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2533–2541, 2006
Co-reporter:Xiao-Dong He;Xue-Wu Ge;Mo-Zhen Wang;Zhi-Cheng Zhang
Journal of Applied Polymer Science 2005 Volume 98(Issue 2) pp:860-863
Publication Date(Web):29 JUL 2005
DOI:10.1002/app.22181
Hollow polymer latex particles containing a hydrophilic core fully encapsulated with a hydrophobic shell were prepared by multistage polymerization followed by neutralization with a base. The diameters of the particles were monodispersed and void fractions of the prepared latex particles as high as 50% were achieved. High instantaneous monomer conversion was found to be the key point to minimize the interdiffusion of the core–shell polymer chains. The influences of the shell crosslinking agent and shell carboxyl content on the hollow morphology were also investigated. The maximum hollow diameter was observed with crosslinking agent contents of 7.5–12.5 wt %. The shell carboxyl content had an appropriate value, and an excess of it resulted in an excentric hollow structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 860–863, 2005
Co-reporter:Dazhen Wu, Xuewu Ge, Yuhong Huang, Zhicheng Zhang, Qiang Ye
Materials Letters 2003 Volume 57(22–23) pp:3549-3553
Publication Date(Web):July 2003
DOI:10.1016/S0167-577X(03)00123-X
Co-reporter:Yonghong Ni, Xuewu Ge, Zhicheng Zhang, Qiang Ye
Materials Letters 2002 Volume 55(Issue 3) pp:171-174
Publication Date(Web):July 2002
DOI:10.1016/S0167-577X(01)00641-3
Au/polyacrylamide (Au/PAM) nanocomposites were successfully prepared in situ by γ (gamma)-irradiation in an ethanol system. The products were characterized by some means including X-ray powder diffraction (XRD), transmission electron microscopy (TEM), IR and UV–VIS spectra. Based on two-aspects, ethanol was used as the solvent. Firstly, it is a very good solvent like water. A lot of inorganic salts and organic monomers can dissolve in it. Secondly, ethanol is also a polar substance. Thus, solventional electron can be easily produced in it during γ-irradiation, which is an important media in the system and plays a crucial role in the synthesis of composites.
Co-reporter:Yonghong Ni, Xuewu Ge, Huarong Liu, Zhicheng Zhang, Qiang Ye, Feng Wang
Materials Letters 2001 Volume 49(3–4) pp:185-188
Publication Date(Web):June 2001
DOI:10.1016/S0167-577X(00)00365-7
α-FeO(OH) nano-rods were synthesized in situ by a simple solution-oxidation reaction at room temperature. The product is characterized by XRD, TEM, XPS and IR, respectively. It was found that the product could be obtained directly in solution when sodium acetate instead of sodium hydroxide was used as the basic agent. The influence on the size and morphology of the product was also studied.
Co-reporter:Xuewu Ge, Yonghong Ni, Huarong Liu, Qiang Ye, Zhicheng Zhang
Materials Research Bulletin 2001 Volume 36(Issue 9) pp:1609-1613
Publication Date(Web):July–August 2001
DOI:10.1016/S0025-5408(01)00638-9
Co-reporter:Yongfei Xu, Mozhen Wang, Xuewu Ge
Radiation Physics and Chemistry (October 2012) Volume 81(Issue 10) pp:1634-1638
Publication Date(Web):1 October 2012
DOI:10.1016/j.radphyschem.2012.05.001
The emulsion polymerization of styrene (St) and methyl methacrylate (MMA) induced by 10 MeV pulsed electron beams (PEB) was investigated. The monomer conversion of MMA and St was found to be very low so that the final prepared poly(methyl methacrylate) (P(MMA)) and polystyrene (PS) latex particles exhibit porous structures, as verified by TEM and SEM observations. The results of dynamic light scattering (DLS) and gel permeation chromatography (GPC) showed that both the particle size and the molecular weight of PS and PMMA latexes decrease with the increase of the absorbed dose. However, the molecular weights and the particle sizes of the PS and PMMA latexes change differently with the irradiation time. This work indicated that emulsion polymerization induced by high energy electron beam has an advantage over that induced by γ-ray or chemical initiators in the preparation of latex with a low molecular weight and porous structure.Highlights► A 10 MeV 400 kGy/min LINAC was used to induce emulsion polymerization. ► Influences of monomer and emulsifier concentration on conversion were studied. ► Molecular weight and particle size of latex on the absorbed dose were studied. ► Resulting latex particles are porous. ► Various nucleation mechanisms co-exist during polymerization.
Co-reporter:Xueping Ge, Mozhen Wang, Qiang Yuan, Hua Wang and Xuewu Ge
Chemical Communications 2009(Issue 19) pp:
Publication Date(Web):
DOI:10.1039/B901094G
Co-reporter:Jianan Zhang, Xuewu Ge, Mozhen Wang, Jianjun Yang, Qingyun Wu, Mingyuan Wu, Nannan Liu and Zhilai Jin
Chemical Communications 2010 - vol. 46(Issue 24) pp:NaN4320-4320
Publication Date(Web):2010/05/11
DOI:10.1039/C002844D
Hybrid hollow microspheres are fabricated successfully from double emulsions stabilized by single-component amphiphilic silica nanoparticles, which were formed and partially modified in situ at the interface of water-in-oil emulsions.
Co-reporter:Lechen Chen, Lizhao Xie, Mozhen Wang and Xuewu Ge
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN2998-2998
Publication Date(Web):2014/12/08
DOI:10.1039/C4TA05898D
Three-dimensional inverse opal SnO2/graphene (IO-SnO2/graphene) microspheres with a size of several tens of microns are first prepared by a well-designed two-step calcination of polystyrene (PS) colloidal crystal template balls infiltrated with the sol precursors of SnO2 and graphene oxide. The polystyrene colloidal crystal template balls are formed by the self-assembly of monodispersed PS microspheres confined in water droplets of an inverse emulsion induced by the slow evaporation of water. Characterization with scanning electronic microscopy, Raman spectra, X-ray diffraction and X-ray photoelectron spectroscopy proved the ordered macroporous inverse opal composed of crystalline SnO2 and in situ reduced GO during the calcination. The pore size depends on the PS microspheres. The UV-vis diffusive reflectance spectra show that the light absorption edge of the prepared IO-SnO2/graphene microspheres can shift more than 400 nm. The photoluminescence spectra indicates that the IO structure and the introduction of rGO make the charge carriers transfer fast and retard the hole/electron recombination in the IO-SnO2/graphene microspheres so that their photocatalytic performance on the UV photolysis of methyl orange is considerably better than that of commercial SnO2 nanoparticles. However, the photocatalytic performance also depends on the content of GO. The addition of 0.06 wt% of GO achieves the best photocatalytic effect. Excessive GO will result in a diminished catalytic activity. This work provides a way to fabricate a new morphological SnO2 based materials with enhanced photocatalytic activity, which helps in the exploration of new photocatalysts with high performance.
Co-reporter:Dezhi Xu, Mozhen Wang, Xuewu Ge, Michael Hon-Wah Lam and Xueping Ge
Journal of Materials Chemistry A 2012 - vol. 22(Issue 12) pp:NaN5791-5791
Publication Date(Web):2012/02/14
DOI:10.1039/C2JM15364E
We report a facile and novel strategy on the fabrication of well-defined raspberry SiO2/polystyrene (SiO2/PS) particles via radiation miniemulsion polymerization. Starting from methacryloxypropyltrimethoxysilane (MPS)-functionalized SiO2 particles (176 nm), raspberry SiO2/PS particles (257 nm) with a submicron SiO2 core decorated by nano-sized PS latex particles (58 nm) are obtained after γ-ray induced miniemulsion polymerization of styrene (St). It is found that MPS grafted density on the surface of submicron SiO2 particles, the weight ratio of St to SiO2 particles (WSt/o-SiO2), as well as the surfactant concentration will affect the morphology and wettability of the resultant SiO2/PS hybrid particles. When the well-defined raspberry SiO2/PS particles are deposited on a blank glass substrate, a dual-size roughness surface topology was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). This film has a static water contact angle as high as 151°. However, this film exhibits a large contact angle hysteresis (∼116°) and strong adhesion to water. Furthermore, this kind of superhydrophobic particulate film can be used as a “mechanical hand” for transportation of small water droplets without loss, thus it may have potential applications in industrial fields.
Co-reporter:Jie Wang, Fuxing Lin, Jinxing Chen, Mozhen Wang and Xuewu Ge
Journal of Materials Chemistry A 2015 - vol. 3(Issue 47) pp:NaN9193-9193
Publication Date(Web):2015/11/04
DOI:10.1039/C5TB01314C
The combination of NIR photothermal therapy and chemotherapy is considered as the promising technique for future cancer therapy. The key point of this technique is the design and synthesis of photothermal agents with high-efficiency photothermal effects and high chemical drug loading capacity. Herein, submicron-sized raspberry-like hollow-structured polypyrrole microspheres (H-PPy) were facilely prepared through in situ polymerization of pyrrole on monodispersed polystyrene (PS) template microspheres with a diameter of 220 nm, followed by the chemical etching of PS templates. The prepared H-PPy microspheres show rapid and remarkable photothermal effects in water under NIR laser irradiation (808 nm) only for 5 min. Further, a model small molecular drug, (S)-(+)-camptothecin (CPT), was loaded into the void core by a simple dispersion–permeation process through the micro-pores on the raspberry-like PPy shell, with a loading capacity of 0.14 mg/(mg H-PPy). The MTT assay and the in vitro NIR-laser triggered release behavior indicated that pure H-PPy microspheres have good biosafety, but the release of loaded CPT into H-PPy microspheres can be achieved with remarkable spatial/temporal resolution after NIR laser irradiation, which results in excellent synergistic effect of photothermal and chemical ablation on HeLa cells, as proved by fluorescence microscopy. This work provides convenient synthesis of a promising cancer therapy agent with high drug-loading capacity and efficient NIR light photothermal effects, which can perfectly achieve the synergistic NIR photothermal therapy and chemotherapy of PPy microspheres.
.jpg)
![Propanoic acid, 2-[[(hexadecylthio)thioxomethyl]thio]-2-methyl-](/data/chemimg/3784300/1360152-64-2.png)
![Propanoic acid, 2-[[(hexadecylthio)thioxomethyl]thio]-2-methyl-](/data/chemimg/3784300/1360152-64-2_b.png)
