Co-reporter:
Journal of Polymer Science Part A: Polymer Chemistry 2017 Volume 55(Issue 9) pp:1536-1546
Publication Date(Web):2017/05/01
DOI:10.1002/pola.28520
ABSTRACTA novel multifunctional amphiphilic graft copolymer has been synthesized consisting of a biodegradable poly(l-aspartic acid) backbone that was decorated by water-soluble poly(ethylene glycol) (PEG) and pH-responsive poly(N,N-diethylaminoethyl methacrylate) (PDEAEMA) side-chains as well as thiol pendant groups. This graft copolymer together with doxorubicin (DOX) formed micelles in water at pH = 10.0 with PDEAEMA and DOX acting as the core and PEG serving as the micellar corona. Upon oxidation, the thiol groups dimerized to form disulfide bonds, thus “locking in” the micellar structure. These crosslinked micelles expanded as the pH was decreased from 7.4 to 5.0 or upon the addition, at pH = 7.4, of glutathione (GSH), a thiol-containing oligopeptide that is present in cancerous cells and cleaves disulfide bonds. At pH = 5.0, GSH addition triggered the disassembly of the micelles. The expansion and disassembly of the micelles have been determined via in vitro experiments to evaluate their DOX release behavior. More importantly, the graft copolymer micelles could enter cells by means of endocytosis and deliver DOX to the nuclei of ovarian cancer BEL-7402 cells. Thus, this polymer and its micelles are promising candidates for drug delivery applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1536–1546
Co-reporter:Yuanyuan Tu, Hailiang Zou, Shudong Lin, Jiwen Hu
Reactive and Functional Polymers 2017 Volume 119(Volume 119) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.reactfunctpolym.2017.08.004
We have recently developed a novel and simple approach based on aqueous solutions of block copolymer micelles for the construction of WFs with wettability ranging from the superhydrophobic to the superamphiphobic regime. That is, the copolymers were initially dispersed into water to yield a micelle solution with the insoluble fluorinated block serving as the micellar core and the water soluble block as the micellar corona. The polyethylene terephthalate (PET) or cotton WFs were then dipped into a copolymer micelle solution and then naturally dried at room temperature before they were cured at high temperature to yield WFs with various degrees of liquid repellency. Further investigation on the mechanism for the formation of either superhydrophobic or superamphiphobic WFs using this aqueous process would facilitate the commercial applications of these water-based coatings. In this contribution, polyethylene terephthalate (PET) films with different liquid repellencies based on copolymer aqueous micelle solutions were prepared via previously reported process, and AFM and XPS techniques were respectively employed to evaluate the morphology and chemical composition of the copolymer-coated PET films. The dependence of water and oil contact angles of PET films on the concentrations of the copolymer micelle solution were evaluated and further employed for the prediction different liquid repellencies of PET WFs. The mechanism for the formation of the superhydrophobic WFs or superamphiphobic WFs was also proposed.Mechanism study on the approach for building woven fabric (WF) with wettability from superhydrophobicity to superamphiphobicity based on diblock copolymer micelles aqueous solution.Download high-res image (90KB)Download full-size image
Co-reporter:Lei Miao, Yang Yang, Yuanyuan Tu, Shudong Lin, Jiwen Hu, Zhuo Du, Min Zhang, Yue Li
Reactive and Functional Polymers 2017 Volume 115(Volume 115) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.reactfunctpolym.2017.04.004
Reported herein is a chiral resolution polysulfone membrane prepared via mussel-inspired chemistry. Polysulfone membranes were modified with dopamine, which underwent in situ polymerization on the membrane substrate, and β-cyclodextrin was used as a chiral selector. The preparation conditions were optimized and the resultant membrane obtained under these conditions showed desirable water permeability (~ 24.0 L/(m2·h·bar)) and surface hydrophilicity (contact angle is lower than 37.1 ± 3.4°). The polydopamine layer exhibited desirable stability in a series of aqueous solutions with pH values ranging from 4.0–6.0 or in isopropanol for less than an hour (detachment ratio was lower than 1.2%). Characterization of the surface morphology and XPS elemental analysis revealed that the membrane surface was fully coated by polydopamine and a β-cyclodextrin monolayer formed on the surface of the polydopamine coating. The grafting density of β-cyclodextrin calculated from the XPS results was ~ 11.5 mg/m2. The optimal pH value for the resolution of D- or L-tryptophan feed solution was 5.90 and a low concentration of the feed solution provided a high resolution efficiency. The enantiomeric excess (e.e.) value of the membrane for Trp racemic mixture achieved to ~ 3.2% with the feed solution of tryptophan racemic mixture was 5 × 10− 5 mol/L and the operating pressure was 0.1 MPa. After 3 times of isopropanol-washed regeneration processes, the e.e. value was still stable around to ~ 3%. The mussel-inspired chemically modified membrane exhibited the same mechanical properties as the purely polysulfone-based membrane. The methods and results provided in this paper may facilitate the large-scale production of chiral resolution membranes or other chiral separation membranes with higher performance.
Co-reporter:Zhiwei Yu;Shudong Lin;Guojun Liu;Pei Zhang;Yuanyuan Tu;Hailiang Zou;Yanlong Wei;Zhenzhong Gao
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 14) pp:6349-6358
Publication Date(Web):2017/07/10
DOI:10.1039/C7NJ00178A
We report here a facile and reproducible strategy for fabricating highly dispersible silver nanowires (AgNWs) in organic solvents using poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) diblock copolymers as the dispersant. The copolymers could be assembled into spherical micelles with PMMA as the core and the solvated PAA block as the corona in methanol. Interestingly, when the copolymer micelle solution was mixed with an AgNW dispersion in methanol, the AgNWs precipitated out within no more than a few minutes depending on the concentration of the micelle solution. The precipitate could readily be redispersed in common organic solvents such as chloroform, toluene, etc., which are good solvents for the PMMA block. The mechanism study revealed that while the PAA block served as an anchor that became chemically attached onto the surfaces of the AgNWs, the PMMA block formed a solvated “buoy” to allow the AgNWs to remain dispersed in the solvent. Transparent conductive glass (TCG) from the modified AgNWs and PMMA was also produced, suggesting that the modified AgNWs could also be well dispersed within the polymer matrix. Although there are reports on the preparation of dispersible inorganic particles using copolymers as a dispersant, the strategy reported in this article is believed to be novel, facile, and quite simple, and can be used as a concept and a universal tool for surface modification of other inorganic nanoparticles from specifically designed and prepared copolymers.
Co-reporter:Shengyu Hu, Shudong Lin, Yuanyuan Tu, Jiwen Hu, Yan Wu, Guojun Liu, Fei Li, Fameng Yu and Tingting Jiang
Journal of Materials Chemistry A 2016 vol. 4(Issue 9) pp:3513-3526
Publication Date(Web):27 Jan 2016
DOI:10.1039/C5TA08694A
Aramid nanofiber (ANF)-coated separators were successfully prepared by the dip-coating of a cationized polypropylene (PP) porous separator in an ANF dispersion in DMSO. The ANFs were successfully coated onto the surface of the cationized PP separator as demonstrated by FT-IR and XPS measurements and the ANFs could be directly observed on the surface of the composite separator via SEM and AFM. The ANF-based coating layers became more uniform and denser as more dip-coating cycles were employed. The gas permeabilities of the separators were strongly influenced by the concentrations of the ANF dispersion and the number of dip-coating cycles. The porosity decreased and a narrower pore size distribution was obtained after the ANFs were coated onto the cationized PP separator. The ANF-coated separators were found to exhibit higher dimensional stabilities than the pristine PP separator. The separators exhibited almost identical endothermic peaks in the DSC experiment and a similar shrink temperature in the DMA experiment but the ANF-coated separator exhibited a higher rupture temperature. The ANF-coated separator retained a comparable mechanical strength with that of the pristine PP separator. The ANF coating layer was mechanically stable and durable in the electrolyte. The ANF-coated separator exhibited comparable C-rate performance and cycling performance in LMO/Li cell systems to that of the PDA–PP separator, and showed significantly better C-rate performance and cycling performance than that of the pristine PP separator. The ANF-coated PP separators exhibited improved safety in a hot oven test in comparison with the pristine PP separator. Thus the ANF-coated separators have great potential for use in lithium ion batteries.
Co-reporter:Lei Miao, Jiwen Hu, Mangeng Lu, Yuanyuan Tu, Xin Chen, Yinwen Li, Shudong Lin, Fei Li, Shengyu Hu
Carbohydrate Polymers 2016 Volume 137() pp:433-440
Publication Date(Web):10 February 2016
DOI:10.1016/j.carbpol.2015.11.001
•Hydroxypropyl cellulose was modified with alkynyl as a crosslinker.•High response rate and well compressive strength of the hydrogel.•The swelling–deswelling and compressive properties can be adjusted.•Heterogeneous and semicontinuous internal structures of the hydrogel.A ternary system thermoresponsive hydrogel, poly(N-isopropylacrylamide-co-hydroxyethyl methylacrylate polycaprolactone)/hydroxypropyl cellulose (or P(NIPAAm-co-HEMAPCL)/HPC), was prepared via “alkynyl/azide” click chemistry between the azide modified graft copolymer P(NIPAAm-co-HEMAPCL-N3) and the alkynyl modified HPC (or alkynyl-HPC). The structures of P(NIPAAm-co-HEMAPCL-N3) and alkynyl-HPC were characterized by 1H NMR, SEC and FT-IR, and the results demonstrated that the mole ratio of the alkynyl and azide functional groups, and the feed ratios of HPC, PCL, and PNIPAAm could be easily adjusted. The incorporation of PCL and HPC dramatically enhanced the compression modulus of the P(NIPAAm-co-HEMAPCL)/HPC hydrogel, which ranged from 500 to 1000 g/cm2. Due to the immiscibility of HPC and PCL, a heterogeneous and semicontinuous structure was observed via SEM. The incorporation of HPC accelerated the water absorption rate and enhanced the hydrogel's ability to shed water. The swelling–deswelling and compressive properties could also be adjusted by changing the feeding ratio. The hydrogel exhibited reversible swelling–deswelling behavior after three “swelling–deswelling” cycles.
Co-reporter:Hailiang Zou;Shudong Lin;Yuanyuan Tu;Fei Li;Guojun Liu;Shengyu Hu;Gonghua Yang;Zhiwei Yu
Advanced Materials Interfaces 2016 Volume 3( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/admi.201500693
Many strategies have been developed to prepare superamphiphobic fabrics that strongly repel water- and oil-borne contaminants and etchants. However, the common drawback in these reported strategies is the use of organic solvents, which should be eliminated or reduced for practical applications. In this paper, the diblock copolymer of poly(2-perfluorooctylethyl acrylate)-block-poly(glycidyl methacrylate- radom-methoxy oligoethyleneglycolyl methacrylate) [PFOEA-b-P(GMA-r-mOEGMA)]is synthesized via atom transfer radical polymerization and used to coat cotton and poly(ethylene terphthalate) fabrics from an aqueous process. It is found that fabrics with tunable and robust wettablity can be prepared from copolymer solution at different concentrations. For example, fabrics coated at a copolymer solution concentration of 22.8 mg mL-1 are superamphiphobic. This process of current stratey is environment-friendly, simple, and reproducible, and may find commercial applications.
Co-reporter:Yangmiao Mo, Shudong Lin, Yuanyuan Tu, Guojun Liu, Jiwen Hu, Feng Liu and Jun Song
RSC Advances 2016 vol. 6(Issue 64) pp:58871-58883
Publication Date(Web):08 Jun 2016
DOI:10.1039/C6RA10822A
A novel amphiphilic binary graft copolymer poly(glycidyl methacrylate)-graft-[poly(2-cinnamoyl-oxyethyl methacrylate)-random-methoxy polyethylene glycol] (PGMA-g-(PCEMA-r-MPEG)) was successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and click reaction, in which alkyne-end-functionalized poly(2-cinnamoyloxyethyl methacrylate) (PCEMA–CCH) and poly(ethylene glycol) methyl ether (MPEG–CCH) were grafted onto a poly(3-azide-2-hydroxy-propyl methacrylate) (P(GMA-N3) backbone. This polymer was used to prepare stable unimolecular micelles (UMMs), which could be produced using either high or low polymer concentrations. Since water is a good solvent only for MPEG but a poor solvent for both PGMA and PCEMA, the hydrophobic PGMA and PCEMA segments aggregated together to form a dense core that was surrounded by a corona based on the soluble MPEG segments. PCEMA was photo-crosslinkable, and thus the UMMs could be crosslinked by shining UV light on the system to yield permanent UMMs. The morphologies of the UMMs were characterized by TEM, AFM, and DLS. Both the TEM and AFM observations indicated that the crosslinked UMMs had a diameter of ∼13 nm, while the DLS measurements indicated they had a diameter of ∼34 nm. The unimolecular state of the micelles was confirmed by SEC, as well as a comparison of the theoretical mass per graft copolymer molecule with that of an individual micelle. Moreover, the morphology of the UMMs was unperturbed by the crosslinking reaction although they became more compact and had a slightly smaller diameter.
Co-reporter:Fei Li, Yuanyuan Tu, Jiwen Hu, Hailiang Zou, Guojun Liu, Shudong Lin, Gonghua Yang, Shengyu Hu, Lei Miao and Yangmiao Mo
Polymer Chemistry 2015 vol. 6(Issue 37) pp:6746-6760
Publication Date(Web):07 Aug 2015
DOI:10.1039/C5PY00903K
Reported herein is the preparation of poly((glycidyl methacrylate)-co-(ethylene glycol dimethacrylate)) raspberry-like colloidal particles (also denoted as RPs) bearing micro-/nano-scale surface roughness and the fabrication of superhydrophobic films with tunable adhesion derived from the RPs after their fluorination. The RPs were prepared via the one-pot dispersion polymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA). The size and the surface roughness of the RPs can be readily tuned by adjusting the polymerization parameters, including the temperature, the feed monomer mole ratio, the initiator concentration, and so on. A possible mechanism of the formation of RPs was proposed according to the morphological evolution observed during the polymerization process as monitored via transmission electron microscopy (TEM), scanning electron microscopy (SEM), and size variation as evaluated with dynamic light scattering (DLS) measurements. Fluorinated RPs (also denoted as FRPs) with various fluorination degrees were further prepared by reaction between the epoxy groups of the RPs and the thiol group of perfluorodecanethiol (PFDT). The raspberry-like morphology of the FRPs was maintained as confirmed via SEM observation. By only changing the surface chemistry rather than the roughness, superhydrophobic films with tunable superhydrophobic properties capable of mimicking wettabilities ranging from those of lotus leaves to those of rose petals were easily prepared by drop-casting dispersions of FRPs onto glass substrates.
Co-reporter:Ganwei Zhang, Jiwen Hu, Yuanyuan Tu, Guping He, Fei Li, Hailiang Zou, Shudong Lin and Gonghua Yang
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 29) pp:19457-19464
Publication Date(Web):23 Jun 2015
DOI:10.1039/C5CP02751A
The diblock copolymer poly[2,2,2-trifluoroethyl methacrylate-r-styrene]-block-poly[(2-cinnamoyloxyethyl methacrylate)] [P(TFEMA-r-Sty)-b-PCEMA] was synthesized via atom transfer radical polymerization. The copolymer underwent self-assembly in TFEMA/CH2Cl2 to form spherical micelles. Photo-cross-linking of the PCEMA domains of these micelles yielded cross-linked nanoparticles. The cross-linked nanoparticles were subsequently cast from CH2Cl2/methanol solvent mixtures at methanol volume fractions of more than 30% to yield rough surfaces bearing small nanobumps on micron-sized aggregations that were connected together to form cross-linked nanoparticles. These surfaces were superhydrophobic with a water contact angle of 161 ± 1° and a sliding angle of 6 ± 1°. Spraying these nanoparticles onto substrates exhibiting microscale roughness, such as filter paper, by a traditional coating technique also created superhydrophobic surfaces. A thin layer of nanoscale spherical protrusions was observed on the microscale fibers of filter paper by scanning electron microscopy. The coated filter paper samples exhibited a water contact angle and a sliding angle of 153 ± 1° and 9 ± 1°, respectively.
Co-reporter:Yang Yang, Lei Miao, Jiwen Hu, Guojun Liu, Yuanyuan Tu, Shudong Lin, Feng Liu, Fei Li, Yan Wu, Ganwei Zhang and Hailiang Zou
Journal of Materials Chemistry A 2014 vol. 2(Issue 27) pp:10410-10423
Publication Date(Web):23 Apr 2014
DOI:10.1039/C4TA01481B
An amphiphilic binary graft copolymer polysulfone-graft-[poly(methyl methacrylate)-random-poly(acrylic acid)], PSf-g-(PMMA-r-PAA), was synthesized via a combination of atom transfer radical polymerization (ATRP) and click chemistry. This copolymer and polysulfone (PSf) were used to prepare porous membranes through the phase inversion method, which involved dissolving the polymers in a common solvent N-methyl pyrrolidone (NMP), casting the solution onto a glass plate to obtain a film, and subsequently immersing this film into a coagulant (a mixture of dimethylformamide and water at a given pH). The surfaces of the membrane and its pore walls were covered by the copolymer, and these surfaces were enriched with PAA domains due to the immiscibility of PAA and PSf and the miscibility of PMMA and PSf. More specifically, while the hydrophobic PMMA component served as an anchor to fix the graft copolymer onto the PSf bulk substrate, the hydrophilic PAA component assembled and became exposed at the surfaces of the membrane and the pore walls. Factors influencing this surface AA concentration or carboxyl group content (CGC) enrichment and the surface and pore morphologies of the membranes include the ratio between the amount of the copolymer and PSf in the mixture, the solvent quality of the coagulant for PSf, and the temperature as well as the pH of the coagulant. These factors have been systematically adjusted to optimize the hydrophilization of the PSf membrane and the resultant membranes have been characterized by water contact angle (WCA) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Optimization of the phase inversion process yielded membranes with nearly complete surface coverage by PAA, even when the graft copolymer represented only 8 wt% of the membrane's composition. The hydrophilized membranes exhibited increased water flux and even pH-responsive water flow without adversely affecting their mechanical properties. In addition, these hydrophilic membranes exhibited long-term stability. Therefore, this novel binary amphiphilic graft copolymer-based approach for membrane modification may be of commercial value.
Co-reporter:Feng Liu, Jiwen Hu, Guojun Liu, Shudong Lin, Yuanyuan Tu, Chengmin Hou, Hailiang Zou, Yang Yang, Yan Wu and Yangmiao Mo
Polymer Chemistry 2014 vol. 5(Issue 4) pp:1381-1392
Publication Date(Web):26 Nov 2013
DOI:10.1039/C3PY01316B
Alkyne end-tagged poly(ethylene glycol) methyl ether, polystyrene, and poly(tert-butyl acrylate) (denoted as MPEG–CCH, PS–CCH, and PtBA–CCH, respectively) were grafted randomly onto a (PGMA–N3) backbone via “click” chemistry to produce a series of ternary graft copolymers PGMA-g-(MPEG-r-PtBA-r-PS). The selective hydrolysis of the PtBA chains into poly(acrylic acid) (PAA) yielded PGMA-g-(MPEG-r-PAA-r-PS). Since MPEG and PAA were soluble in water while PS was soluble in decahydronaphthalene (DN), the graft copolymers were good surfactants for emulsifying DN in water. Various factors affecting the emulsification were examined, including the stirring rate, the copolymer composition, and the concentration. Crosslinking of the PAA chains, which were distributed among MPEG chains in the coronas of the emulsion droplets, with a diamine produced a novel structure – “nanocapsules” bearing partially crosslinked coronas.
Co-reporter:Yinhui Li, Shudong Lin, Jiwen Hu, Guojun Liu, Gangwei Zhang, Yuanyuan Tu, Hongsheng Luo, Wei Li
Carbohydrate Polymers 2014 Volume 102() pp:489-496
Publication Date(Web):15 February 2014
DOI:10.1016/j.carbpol.2013.11.062
•Amylose with various morphologies induced-assembly by metal ions in water.•The capture behavior of amylose to metal ions was preliminarily investigated.•Amylose can completely combine with low-concentration metal ions in aqueous solution.•An alternative strategy for recycling precious metals and reducing water pollution.Cu2+/amylose assemblies of various sizes were prepared through the Cu2+ ion induced-assembly of amylose. These assembly structures were characterized via transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), dynamic light scattering (DLS), 1H NMR analysis, fluorescence spectroscopy (FL) and UV–vis absorption spectroscopy (UV–vis). The results from these characterizations revealed the existence of a complexation effect and/or a bridging effect between the hydroxyl groups of amylose and Cu2+ ions, and that the formation of the hydrophobic domains promoted the formation of Cu2+/amylose assemblies. The use of other metal ions to induce the formation of spherical, flower- and wire-like amylose assemblies was investigated as well. A preliminary investigation on the ability of amylose to capture various metal ions was also performed, and the results of this work demonstrated that amylose could bind quantitatively metal ions that were at low concentrations. This work provided an alternative strategy for the recovery of precious metals from metal ion-containing aqueous solutions and the reduction of water pollution.
Co-reporter:Chengmin Hou, Shudong Lin, Feng Liu, Jiwen Hu, Ganwei Zhang, Guojun Liu, Yuanyuan Tu, Hailiang Zou and Hongsheng Luo
New Journal of Chemistry 2014 vol. 38(Issue 6) pp:2538-2547
Publication Date(Web):13 Mar 2014
DOI:10.1039/C3NJ01398G
Poly(2-hydroxyethyl methacrylate) (PHEMA) end-capped with living chloride and alkyne groups was synthesized via ATRP of HEMA using CuCl/CuCl2/2,2′-bipyridine as a catalyst in a solvent mixture of methanol and 2-butanone. The effects of parameters including the initiator, solvent, temperature and initial monomer to initiator ratios on polymerization were studied in terms of polymerization kinetics, the degree of polymerization (DP) and molar mass dispersity (Đ) of the resulting PHEMA polymer. ATRP of HEMA using propargyl 2-bromoisobutyrate (PBiB) as an initiator was poorly controlled, but those using 3-(trimethylsilyl)propargyl 2-bromoisobutyrate (TMSPBiB) and 3-(triisopropysilyl)propargyl 2-bromoisobutyrate (TiPSPBiB) as initiators were well-controlled. Moreover, the apparent propagation rate constant for ATRP of HEMA using the TMSPBiB initiator was higher than that using the TiPSPBiB initiator. The solvent mixture of methanol–2-butanone at different compositions greatly affected the polymerization controllability. A high molecular weight PHEMA sample with a DP of 1000 and a Đ of 1.34 was obtained under appropriate conditions. The poly(2-hydroxyethyl methacrylate)-block-poly(butyl acrylate) (PHEMA-b-PBA) diblock copolymer was prepared through ATRP of BA using (CH3)3Si–CC–PHEMA–Cl as a macroinitiator. The methoxyl polyethylene glycol-block-poly(2-hydroxyethyl methacrylate) (MPEG-b-PHEMA) diblock copolymer was prepared by click reaction between MPEG-N3 and HCC–PHEMA–Cl. These two reactions demonstrated the reactivity of the asymmetric functional groups end-capping the PHEMA, and further provided modular examples for the synthesis of a novel well-defined (co)polymer with complex architectures.
Co-reporter:Jinheng Shi;Hongsheng Luo;Dingshu Xiao;Ganwei Zhang;Yinhui Li;Baofeng Lin;Xingquan Liang;Yuanyuan Tu
Journal of Applied Polymer Science 2014 Volume 131( Issue 2) pp:
Publication Date(Web):
DOI:10.1002/app.39780
ABSTRACT
Cassava xanthogenate and their derivatives, as adsorbents to remove Pb2+ from aqueous solution, are studied based upon orthogonal factorial design. The structural and thermal properties, adsorption performance as well as equilibrium-kinetics are comprehensively investigated with multiple tools, such as Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and UV–visible spectrum technique. The influence of multiple parameters, including initial Pb2+ concentrations, compositions, pH values, and temperatures, on the adsorption performance is emphasized. The crosslinked cassava xanthogenate serves as an effective bio-sorbent to remove Pb ions from aqueous solution, allowing regeneration in dilute acid solution. The findings in this study are beneficial for the development of adsorbents from cassava waste biomass and may contribute to environment recovery in “nature-to-nature” manner. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39780.
Co-reporter:Jinheng Shi;Hongsheng Luo;Dingshu Xiao;Yuanyuan TU;Baofeng Lin;Xingquan Liang
Advances in Polymer Technology 2014 Volume 33( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/adv.21424
ABSTRACT
The cross-linked cassava xanthate (CCX) was synthesized and used to remove Cr6+ ions from aqueous solution. The influence of multiple factors on the sorption process, including pH, temperature, contact time, sulfur content, and sorbent/sorbate ratio, was quantitatively investigated. The sorption capacity of the CCX was confirmed under different conditions. The adsorption equilibrium was fitted to Langmuir and Freundlich isotherms. The Cr-containing cross-linked cassava xanthate (CCX-Cr) could be cyclically regenerated by HNO3 solution. The pyrolysis of the CCX and CCX-Cr was measured using Fourier transform infrared spectroscopy and thermo-gravimetric/differential thermal analysis coupling method. The CCX had higher percentage of the residues than the CCX-Cr due to the ion exchange mechanism in the adsorption process.
Co-reporter:Feng Liu, Shudong Lin, Zuoquan Zhang, Jiwen Hu, Guojun Liu, Yuanyuan Tu, Yang Yang, Hailiang Zou, Yangmiao Mo, and Lei Miao
Biomacromolecules 2014 Volume 15(Issue 3) pp:
Publication Date(Web):February 15, 2014
DOI:10.1021/bm4018484
Three ternary graft copolymers bearing polystyrene (PS), poly(ethylene glycol) methyl ether (MPEG), and poly(acrylic acid) (PAA) side chains were synthesized and characterized. At pH = 7.4, these copolymers stabilized doxorubicin (DOX)-containing benzyl benzoate (BBZ) nanoemulsion droplets in water and formed a compact polymer layer to inhibit DOX release. Upon lowering the solution pH to 5.0, the AA groups dissociated less and became less soluble. Moreover, the neutralized AA groups formed presumably H-bonded complexes with the EG units, reducing the solubility of the EG units. This dual action drastically shifted the hydrophilic and hydrophobic balance of the copolymer and caused the original stabilizing polymer layer to rupture and the nanoemulsion droplets to aggregate, releasing DOX. The rate and extent of DOX release could be increased by matching the numbers of PAA and MPEG chains per graft copolymer. In addition, these nanoemulsions were not toxic and entered human carcinoma cells, releasing DOX there. Thus, these nanoemulsions have potential as drug delivery vehicles.
Co-reporter:Hailiang Zou, Shudong Lin, Yuanyuan Tu, Guojun Liu, Jiwen Hu, Fei Li, Lei Miao, Ganwei Zhang, Hongsheng Luo, Feng Liu, Chengmin Hou and Meilong Hu
Journal of Materials Chemistry A 2013 vol. 1(Issue 37) pp:11246-11260
Publication Date(Web):17 Jul 2013
DOI:10.1039/C3TA12224G
We report here a simple and reproducible strategy for fabricating highly durable and robust superhydrophobic cotton fabrics (SCFs) from a series of functional diblock copolymers. These diblock copolymers consisted of both poly(glycidyl methacrylate) (PGMA) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) blocks that were synthesized via sequential atom transfer radical polymerization (ATRP). While the PTFEMA block provides the low surface free energy, the PGMA block serves as an anchor and forms covalent bonds with the surfaces of cotton fibers. These covalent bonds are formed via the epoxy ring-opening reaction between the epoxy groups of the PGMA block and the hydroxyl groups on the surface of the cotton fiber, and self-crosslinking of epoxy groups from PGMA chains. Structures exhibiting nano- and microscale roughness were created in one-step by combining copolymer-based nanobumps onto surfaces of micro-sized fibers of the cotton fabric, as confirmed by SEM and AFM analysis. The modified cotton fabrics show excellent water repellency with water contact angles (WCAs) of ∼163° and water sliding angles (WSAs) of ∼3° under optimized conditions. Since the low-fluorinated PTFEMA chains are chemically bound to the cotton fibers, the SCFs possess long-term stability, ultra-high durability and robustness. In particular, these SCFs withstood mechanical abrasion by sandpaper, strong laundering conditions, ultrasonication treatment in tetrahydrofuran (THF) or trifluorotoluene (TFT), soaking in a wide range of organic solvents, as well as acidic and basic aqueous solutions, exposure to UV-irradiation and even refluxing in TFT or THF.
Co-reporter:Ganwei Zhang, Jiwen Hu, Guojun Liu, Hailiang Zou, Yuanyuan Tu, Fei Li, Shengyu Hu and Hongsheng Luo
Journal of Materials Chemistry A 2013 vol. 1(Issue 20) pp:6226-6237
Publication Date(Web):02 Apr 2013
DOI:10.1039/C3TA10722A
Random bi-functional copolymers bearing fluorinated units and sol–gel forming units were prepared and used together with silica particles in a one-pot process for preparing superamphiphobic coatings. The copolymers P(FOEA-r-IPSMA) were prepared by atom transfer radical polymerization (ATRP) of 2-(perfluorooctyl)ethyl acrylate (FOEA) and 3-(triisopropyloxy)silylpropyl methacrylate (IPSMA). The uniform silica particles were prepared using a modified Stöber process. Stirring P(FOEA-r-IPSMA), silica, water, and HCl together with substrates triggered the sol–gel reactions of the IPSMA units. These involved first the hydrolysis of IPSMA to yield silanol groups and then the condensation of the IPSMA silanol groups among themselves, and with silanol groups on silica or glass surfaces or with hydroxyl groups on cotton or filter paper. At optimized mass ratios of P(FOEA-r-IPSMA) to silica, the resultant coatings consisted of lightly covered silica particles that were embedded in a crosslinked P(FOEA-r-IPSMA) film. By optimizing the molar ratio between FOEA and IPSMA in P(FOEA-r-IPSMA), the rough particulate coatings on cotton, filter paper, and glass plates exhibited superamphiphobicity. More importantly, the particulate coatings were resistant to solvent extraction and NaOH etching.
Co-reporter:Guping He, Jiwen Hu, Guojun Liu, Yinhui Li, Ganwei Zhang, Feng Liu, Jianpin Sun, Hailiang Zou, Yuanyuan Tu, and Dingshu Xiao
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 7) pp:2378
Publication Date(Web):March 12, 2013
DOI:10.1021/am400058k
Reported are the formation of rough particulate films from cross-linked diblock copolymer vesicles and nanotubes and the wetting properties of the resultant films. The diblock copolymers used were F66M200 and F95A135, where the subscripts denote the repeat unit numbers, whereas M, A, and F denote poly(2-cinnamoyloxyethyl methacrylate), poly(2-cinnamoyloxyethyl acrylate), and poly(2,2,2-trifluoroethyl methacrylate), respectively. The precursory polymers to F66M200 and F95A135 were prepared by atom transfer radical polymerization. In 2,2,2-trifluoroethyl methacrylate (FEMA), a selective solvent for F, vesicles and tubular micelles were prepared from F66M200 and F95A135, respectively. Photo-cross-linking the M and A blocks of these aggregates yielded hollow nanospheres and nanotubes bearing F coronal chains. These particles were dispersed into CH2Cl2/methanol, where CH2Cl2 was a good solvent for both blocks and methanol was a poor solvent for F. Casting CH2Cl2/methanol dispersions of these particles yielded films consisting of hierarchically assembled diblock copolymer nanoparticles. For example, the hollow nanospheres fused into microspheres bearing nanobumps after being cast from CH2Cl2/methanol at methanol volume fractions of 30 and 50%. The roughness of these films increased as the methanol volume fraction increased. The films that were cast at high methanol contents were superhydrophobic, possessing water contact angles of ∼160° and water sliding angles of ∼3°.Keywords: block copolymers; hierarchical assembly; micellization; self-assembly; superhydrophobicity;
Co-reporter:Ganwei Zhang, Shudong Lin, Ian Wyman, Hailiang Zou, Jiwen Hu, Guojun Liu, Jiandong Wang, Fei Li, Feng Liu, and Meilong Hu
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 24) pp:13466
Publication Date(Web):November 20, 2013
DOI:10.1021/am404317c
Reported herein is the growth of bifunctional random copolymer chains from silica particles through a “grafting from” approach and the use of these copolymer-bearing particles to fabricate superamphiphobic coatings. The silica particles had a diameter of 90 ± 7 nm and were prepared through a modified Stöber process before atom transfer radical polymerization (ATRP) initiators were introduced onto their surfaces. Bifunctional copolymer chains bearing low-surface-free-energy fluorinated units and sol–gel-forming units were then grafted from these silica particles by surface-initiated ATRP. Perfluorooctyl ethyl acrylate (FOEA) and 3-(triisopropyloxy)silylpropyl methacrylate (IPSMA) were respectively used as fluorinated and sol–gel-forming monomers in this reaction. Hydrolyzing the IPSMA units in the presence of an acid catalyst yielded silica particles that were adorned with silanol-bearing copolymer chains. Coatings were prepared by spraying these hydrolyzed silica particles onto glass and cotton substrates. A series of four different copolymer-functionalized silica particles samples bearing copolymers with similar FOEA molar fractions (fF) of ∼80% but with different copolymer grafting mass ratios (gm) that ranged between 12.3 wt % and 58.8 wt %, relative to silica, were prepared by varying the polymerization protocols. These copolymer-bearing silica particles with a gm exceeding 34.1 wt % were used to coat glass and cotton substrates, yielding superamphiphobic surfaces. More importantly, these particulate-based coatings were robust and resistant to solvent extraction and NaOH etching thanks to the self-cross-linking of the copolymer chains and their covalent attachment to the substrates.Keywords: amphiphobic; ATRP; coating; silica particles; sol−gel chemistry; superamphiphobic; surface grafting;
Co-reporter:Yinhui Li, Jiwen Hu, Guojun Liu, Ganwei Zhang, Hailiang Zou, Jinheng Shi
Carbohydrate Polymers 2013 Volume 92(Issue 1) pp:555-563
Publication Date(Web):30 January 2013
DOI:10.1016/j.carbpol.2012.08.102
Reported are the synthesis and characterization of CuS composite nanowires and microspheres in the presence of amylose. The preparation involved first the complexation of amylose with Cu2+ of CuCl2 at 70 °C. Cu2+ complexation was confirmed by a conductivity reduction of CuCl2 after amylose addition. Also, the aggregation state of the amylose changed after Cu2+ as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). At the Cu2+ to α-d-glucopyranosyl unit molar ratio r of 0.70 and 1.41, the amylose aggregated into microspheres that were approximately 150 and 250 nm in diameter. Adding sodium thiosulfate resulted in the production of an amorphous precipitate consisting presumably of CuS2O3. At r = 0.70 and 1.41, CuS2O3 precipitated inside the template of Cu2+/amylose microspheres as nanoparticles, while a twisted nanowire-like structure was produced at r = 0.92. CuS2O3 decomposed under heating at 100 °C to yield crystalline CuS nanoparticles.Graphical abstractHighlights► Synthesis of CuS/amylose nanowires and microspheres in the presence of amylose. ► Preparation of CuS/amylose microspheres with hierarchical structure. ► Shape/size-controlled synthesis of CuS/amylase composite particles. ► Detailed characterization of CuS/amylose composite particle particles.
Co-reporter:Chengmin Hou, Jiwen Hu, Guojun Liu, Jiandong Wang, Feng Liu, Heng Hu, Ganwei Zhang, Hailiang Zou, Yuanyuan Tu, and Bing Liao
Macromolecules 2013 Volume 46(Issue 10) pp:4053-4063
Publication Date(Web):May 1, 2013
DOI:10.1021/ma400179r
Six binary graft copolymers were synthesized, and their graft segregation in bulk was investigated. The copolymers were prepared by a one-pot method involving the quantitative grafting of alkyne-end-functionalized poly(n-butyl acrylate) (PBA-C≡CH) and poly(2-cinnamoyloxyethyl methacrylate) (PCEMA-C≡CH) onto poly(3-azide-2-hydroxypropyl methacrylate) (P(GMA-N3)) via click chemistry. Of these copolymers, three had a total PBA and PCEMA molar grafting density g of ∼20%, and their PBA volume fractions VB among PBA and PCEMA varied between 28% and 57%. VB was constant at ∼57%, while g varied between 9.8% and 29.5% for the other three samples. Bulk films were obtained by slowly evaporating the solvent from cast solutions of these copolymers. These films were then annealed above the glass transition temperatures of PBA and PCEMA to facilitate graft segregation. The graft segregation patterns were examined by performing transmission electron microscopy (TEM) analysis of thin sections of these films. The TEM results suggested that the grafted PBA chains formed a disordered wormlike phase in a PCEMA matrix at VB = 28%. At VB = 42% and 57%, PBA and PCEMA seemed to form alternating lamellae. In the former case, the PBA layers were thinner than the PCEMA layers, while the PBA layers were thinner in the latter case. All three samples with VB ∼ 57% probably possessed a lamellar morphology. The periodicity of the lamellae increased and the long-range ordering deteriorated as g increased.
Co-reporter:Feng Liu, Jiwen Hu, Guojun Liu, Chengmin Hou, Shudong Lin, Hailiang Zou, Ganwei Zhang, Jianping Sun, Hongsheng Luo, and Yuanyuan Tu
Macromolecules 2013 Volume 46(Issue 7) pp:2646-2657
Publication Date(Web):March 19, 2013
DOI:10.1021/ma302663u
Grafting three types of polymer chains onto the backbone of a fourth polymer yielded a ternary graft copolymer. The copolymer dispersed oil droplets in water with one type of graft stretching into the oil phase, the second type forming a thin membrane separating the two phases, and the third type stretching into the water phase. Since the second type was also photo-cross-linkable, shining UV light on the system produced permanent nanocapsules. To produce the graft copolymer, the backbone polymer used was poly(3-azido-2-hydroxypropyl methacrylate), P(GMA-N3). The grafts used were all end-functionalized by alkyne groups, and the polymers were poly(ethylene glycol) methyl ether (MPEG), polystyrene (PS), and poly(2-cinnamoyloxyethyl methacrylate) (PCEMA), respectively. Evidently, MPEG was water-soluble, PS was soluble in the used oil decahydronaphthalene (DN), and PCEMA was photo-cross-linkable and soluble in neither water nor DN. The grafts denoted as MPEG–C≡CH, PS–C≡CH, and PCEMA–C≡CH were coupled to P(GMA-N3) via click chemistry between the azide and alkyne units. Under the used conditions, the one-pot grafting reactions were quantitative.
Co-reporter:Ganwei Zhang;Guping He;Hailiang Zou;Feng Liu;Chengmin Hou;Hongsheng Luo ;Yuanyuan Tu
Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 8) pp:1852-1864
Publication Date(Web):
DOI:10.1002/pola.26568
Abstract
Fluorinated copolymers with statistical structure of azeotropic or gradient composition were prepared from heterogeneous atom transfer radical copolymerizations of styrene (S) and 2,2,2-trifluoroethyl methacrylate (T). The polymerization kinetic studies show that while the propagation rate constant of S increased with a decreasing S content in the comonomer feed ratio, the propagation rate of T decreased with decreases of the S content in the comonomer feed ratio. The polymerization rate and controllability of the heterogeneous ATRP of S and T were regulated by the solubility of Cu(II)/ligand in the reaction mixture, based on a mechanistic analysis and solubility tests of the Cu(II)/ligand system in the reaction media. The reactivity ratios of S and T were 0.22 and 0.35, as evaluated from kinetic analysis of monomer conversions higher than 35%. These statistical polymers self-assembled in T to form giant vesicles GVs) with broad diameter distribution in the range of 1–10 μm. Unlike the methods normally used to prepare gradient copolymers by spontaneous controlling with feeding model or batch polymerization of comonomers with obvious differences in the reactivity ratio, in this contribution, we report a novel synthetic strategy for preparing gradient copolymers can also be prepared from both monomers with very similar reactivity ratio. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Co-reporter:Yinhui Li, Jiwen Hu, Guojun Liu, Jinheng Shi, Wei Li, Dingshu Xiao
Polymer 2012 Volume 53(Issue 15) pp:3297-3303
Publication Date(Web):6 July 2012
DOI:10.1016/j.polymer.2012.05.015
Synthesized and characterized were silica/amylose composite particles with interesting morphologies which we named as silica/amylase composite core–shell particles. Amylose is soluble in hot water. Ethanol addition to a volume fraction fEtOH of 75% caused amylose to aggregate into globules with diameters ∼50 nm and smaller. After ammonia and tetraethoxysilane (TEOS) addition, TEOS underwent sol-gel reactions in the presence of amylose. The reactions eventually yielded core–shell nanospheres with their core enriched by amylose and shell consisting mostly of fused SiO2-wrapped amylose or SiO2@amylose nanoparticles. Under a given set of experimental conditions, the equilibrium nanospheres had a well-defined size. The shell thickness increased as mS/mA increased, where mS denoted the amount of SiO2 obtainable from the amount of TEOS precursor added and mA denoted the amylose amount. After pyrolysis of the nanospheres prepared at relatively high mS/mA values, interesting hollow silica particles with nano-sized porous walls were obtained.Graphical abstract
Co-reporter:Guping He, Ganwei Zhang, Jiwen Hu, Jianping Sun, Shenyu Hu, Yinhui Li, Feng Liu, Dingshu Xiao, Hailiang Zou, Guojun Liu
Journal of Fluorine Chemistry 2011 Volume 132(Issue 9) pp:562-572
Publication Date(Web):September 2011
DOI:10.1016/j.jfluchem.2011.05.027
We report the preparation of low-fluorinated homopolymer via heterogeneous atom transfer radical polymerization (ATRP) of 2,2,2-trifluoroethyl methacrylate (TFEMA) using 2,2′-bipyridine (bpy), N,N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA), and tris(2-(dimethylamino)ethyl)amine (Me6TREN) as representatives for di-, tri-, and tetradentate amine ligands, respectively. The ATRP was better controlled, yielding polymers with controlled molecular weights and low polydispersities (Mw/Mn ca. 1.11) when bpy was used as a ligand than when PMDETA was used. This was further supported by the results of our kinetic and chain extension studies. However, the ATRP of TFEMA had lower monomer conversions and gel formation when Me6TREN was used as the ligand. Further reported are the thermal-properties, as well as the surface properties of the films from the resulting polymers with different molecular weights.Graphical abstractThis paper reports low-fluorinated homopolymer from heterogeneous atom transfer radical polymerization (ATRP) of 2,2,2-trifluoroethyl methacrylate (TFEMA) using bpy, PMDETA, Me6TREN as representative for di-, tri-, and tetradentate amines ligands, respectively.Highlights► ATRP of 2,2,2-trifluoroethyl methacrylate was carried out using different ligands. ► Kinetic studies were conducted to elucidate the reason for controllabilty of ATRP. ► The thermal-properties of the resulting polymers with different Mn were reported. ► The surface properties of the films from polymers were reported.
Co-reporter:Jianping Sun;Guojun Liu;Dingshu Xiao;Guping He;Rufeng Lu
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 5) pp:1282-1288
Publication Date(Web):
DOI:10.1002/pola.24540
Abstract
Reported here is a novel approach toward efficient preparation of well-defined cylindrical brushes polymer (CBPs) with both hydrophobic and hydrophilic side chains connected to the linear backbone by interfacial “click” chemistry in two immiscible solvents. The CBPs with high grafting density of more than 95% and molecular polydispersity (Mw/Mn) less than 1.12 can be readily synthesized using present approach. On contrary, the CBPs synthesized from the “click” reaction in a single solvent in homogenous state have low grafting density of less than 55% and molecular polydispersity (Mw/Mn) more than 1.78. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Co-reporter:Zhilei Liu;Jianping Sun;Guping He;Yinghui Li ;Ganwei Zhang
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 16) pp:3573-3586
Publication Date(Web):
DOI:10.1002/pola.24137
Abstract
We report here the synthesis of well-defined homopolymer bearing amino acid diamide, poly(N-acryloyl-L-valine N′-methylamide), via reversible addition fragmentation chain transfer (RAFT) polymerization using alkynyl-functionalized 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl-propionic acid propargyl alcohol ester as chain transfer agent (CTA) and 2,2′-azobis(isobutyronitrile) as initiator. The effects of a variety of parameters, such as temperature and solvent, on RAFT polymerization were examined to determine the optimal control of the polymerization. The controlled nature of RAFT polymerization was evidenced by the controllable molecular weight and low-molecular-weight polydispersity index (Mw/Mn) of resulting homopolymers and further demonstrated to have retained end-group functionality by the fact of the successful formation of block copolymers from further RAFT polymerization by using the resultant polymer as macro-CTA, as well as from “click” chemistry. Thermoresponsive property of the prepared polymer was evaluated in terms of the lower critical solution temperature in aqueous solution by measuring the transmittance variation at 500 nm from UV/vis spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3573–3586, 2010
Co-reporter:Zhilei Liu;Jianping Sun;Guojun Liu
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 22) pp:4922-4928
Publication Date(Web):
DOI:10.1002/pola.24286
Abstract
Homopolymers bearing terminal azide and alkyne groups can be coupled via click chemistry to yield diblock copolymers. When performed in solvents that dissolved both homopolymers, the click reaction was found in this study to be inefficient, probably due to the embedding of the reactive end groups inside the random coils of the polymers. The efficiency was only slightly affected by the addition of a small amount of water into the reaction mixture. However, the reaction efficiency increased dramatically near the water volume fraction where one or both of the reacting polymers began to precipitate. Further increases in water content caused the polymer(s) to undergo macroscopic phase separation and the click reaction efficiency decreased once again. A possible explanation for the observed effect of water on the polymer coupling reaction is proposed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Co-reporter:Fabao Zhao;Jianping Sun;Zhilei Liu;Liang Feng
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 3) pp:364-371
Publication Date(Web):
DOI:10.1002/polb.21898
Abstract
Reported here is self-assembly behavior in selective solvent of diblock copolymers with relatively long corona-forming block compared to core-forming block. Three diblock copolymers, poly(ethylene glycol) monomethyl ether-b-poly(methacryloyl-L-leucine methyl ester), also denoted as MPEG-b-PMALM copolymer, were prepared by fixing MPEG block with an average number of repeating units of 115, whereas varying PMALM block with an average number of repeating unit of 44, 23, 9, respectively. Multiple morphologies, such as sphere, cylinder, vesicle, and their coexisted structures from self-assembly of these diblock copolymers in aqueous media by changing block nonselective solvent and initial polymer concentration used in preparation, were demonstrated directly via TEM observation. These results herein might, therefore, demonstrate as an example that a wide range of morphologies can be accessed not only from “crew-cut micelles” but also from “star-micelles” by controlling over preparation strategies. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 364–371, 2010
Co-reporter:Yinhui Li;Jianping Sun;Ganwei Zhang
Colloid and Polymer Science 2010 Volume 288( Issue 5) pp:567-572
Publication Date(Web):2010 March
DOI:10.1007/s00396-010-2184-z
We report here a novel strategy for fabrication of SiO2 hollow microspheres with urchin-like structure based on templates from directed assembly of block copolymer, poly(2-cinnamoyloxyethyl acrylate)-block-poly(acrylic acid-co-styrene) (PCEA-b-P(AA-co-Sty)). The structures of template from directed assembly of copolymers as well as that of as-obtained hollow SiO2 microspheres were observed by a combination technique of optical microscope, scanning electron microscope, and transmission electron microscopy. It is shown that the hollow microspheres consist of aligned SiO2 “spines” radially growing from the core which are induced a favorable growth by the structures of the template from directed assembly of PCEA-b-P(AA-co-Sty). The “spine” density of the hollow SiO2 sphere can be tuned by controlling the structure of the copolymer with different hydrolysis degree of poly(tert-butyl-acrylate) to PAA, and the ultimate size of the resultant SiO2 hollow sphere can be adjusted by solvent and temperature in the sol–gel process, etc.
Co-reporter:Fa Bao Zhao, Zhi Lei Liu, Jian Ping Sun, Liang Feng, Ji Wen Hu
Chinese Chemical Letters 2009 Volume 20(Issue 2) pp:231-234
Publication Date(Web):February 2009
DOI:10.1016/j.cclet.2008.10.044
Reported here is fabrication of optically active micelles with broad range of morphologies in water, such as spheres, cylinders, and vesicles, from self-assembly of poly(ethylene glycol) monomethyl ether-b-poly- (methacryloyl-L-leucine methyl ester) (MPEG-b-PMALM) copolymer, which was prepared via atom transfer radical polymerization (ATRP) from vinyl monomer bearing chiral amino acid moieties, N-methacryloyl L-leucine methyl ester (MALM), using bromine (Br) end-capped poly(ethylene golycol) monomethylether (MPEG-Br) as macroinitiator in the presence of CuBr/Me6TREN as catalytic system.
Co-reporter:Fabao Zhao;Zhilei Liu;Liang Feng;Jianping Sun
Journal of Polymer Science Part B: Polymer Physics 2009 Volume 47( Issue 14) pp:1345-1355
Publication Date(Web):
DOI:10.1002/polb.21739
Abstract
Optically active poly(ethylene glycol) monomethyl ether-b-poly(methacryloyl-L-leucine methyl ester) (denoted as MPEG-b-PMALM) copolymers were prepared via atom transfer radical polymerization (ATRP), using bromine (Br) end-capped poly(ethylene glycol) monomethyl ether (denoted as MPEG-Br) as macroinitiator in the presence of CuBr/tris(2-dimethylaminoethy1)amine (Me6TREN) as catalytic system. Broad range of morphologies, such as spherical, cylindrical, and vesicular micelles, which were prepared by initially dissolving prepared polymer in organic solvent at different concentration followed by addition various amount of water before dialysis against water to remove any added solvent, was observed by transmission electron microscope (TEM). More detailed chiroptical properties of the micelles/aggregates in aqueous solution were evaluated by circular dichroism (CD) spectroscopy as a function of micelles morphologies, polymer concentration, solvents employed, temperature, etc. The micellar solutions exhibit almost the same CD spectra regardless of its morphologies. The intensity of the CD spectra of the cylindrical micelles decreased in the molar ellipticities as the micellar concentration in water was increased. The Cotton effect was markedly changed when the solvent hydrophobicity was changed by addition of trifluoromethyl ethanol (TFME) to water. The intensity of the CD spectra decreased not too much within the temperature range from 20 °C to 90 °C, indicating good stability of the micelles upon temperature variation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1345–1355, 2009
Co-reporter:Shengyu Hu, Shudong Lin, Yuanyuan Tu, Jiwen Hu, Yan Wu, Guojun Liu, Fei Li, Fameng Yu and Tingting Jiang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 9) pp:NaN3526-3526
Publication Date(Web):2016/01/27
DOI:10.1039/C5TA08694A
Aramid nanofiber (ANF)-coated separators were successfully prepared by the dip-coating of a cationized polypropylene (PP) porous separator in an ANF dispersion in DMSO. The ANFs were successfully coated onto the surface of the cationized PP separator as demonstrated by FT-IR and XPS measurements and the ANFs could be directly observed on the surface of the composite separator via SEM and AFM. The ANF-based coating layers became more uniform and denser as more dip-coating cycles were employed. The gas permeabilities of the separators were strongly influenced by the concentrations of the ANF dispersion and the number of dip-coating cycles. The porosity decreased and a narrower pore size distribution was obtained after the ANFs were coated onto the cationized PP separator. The ANF-coated separators were found to exhibit higher dimensional stabilities than the pristine PP separator. The separators exhibited almost identical endothermic peaks in the DSC experiment and a similar shrink temperature in the DMA experiment but the ANF-coated separator exhibited a higher rupture temperature. The ANF-coated separator retained a comparable mechanical strength with that of the pristine PP separator. The ANF coating layer was mechanically stable and durable in the electrolyte. The ANF-coated separator exhibited comparable C-rate performance and cycling performance in LMO/Li cell systems to that of the PDA–PP separator, and showed significantly better C-rate performance and cycling performance than that of the pristine PP separator. The ANF-coated PP separators exhibited improved safety in a hot oven test in comparison with the pristine PP separator. Thus the ANF-coated separators have great potential for use in lithium ion batteries.
Co-reporter:Yang Yang, Lei Miao, Jiwen Hu, Guojun Liu, Yuanyuan Tu, Shudong Lin, Feng Liu, Fei Li, Yan Wu, Ganwei Zhang and Hailiang Zou
Journal of Materials Chemistry A 2014 - vol. 2(Issue 27) pp:NaN10423-10423
Publication Date(Web):2014/04/23
DOI:10.1039/C4TA01481B
An amphiphilic binary graft copolymer polysulfone-graft-[poly(methyl methacrylate)-random-poly(acrylic acid)], PSf-g-(PMMA-r-PAA), was synthesized via a combination of atom transfer radical polymerization (ATRP) and click chemistry. This copolymer and polysulfone (PSf) were used to prepare porous membranes through the phase inversion method, which involved dissolving the polymers in a common solvent N-methyl pyrrolidone (NMP), casting the solution onto a glass plate to obtain a film, and subsequently immersing this film into a coagulant (a mixture of dimethylformamide and water at a given pH). The surfaces of the membrane and its pore walls were covered by the copolymer, and these surfaces were enriched with PAA domains due to the immiscibility of PAA and PSf and the miscibility of PMMA and PSf. More specifically, while the hydrophobic PMMA component served as an anchor to fix the graft copolymer onto the PSf bulk substrate, the hydrophilic PAA component assembled and became exposed at the surfaces of the membrane and the pore walls. Factors influencing this surface AA concentration or carboxyl group content (CGC) enrichment and the surface and pore morphologies of the membranes include the ratio between the amount of the copolymer and PSf in the mixture, the solvent quality of the coagulant for PSf, and the temperature as well as the pH of the coagulant. These factors have been systematically adjusted to optimize the hydrophilization of the PSf membrane and the resultant membranes have been characterized by water contact angle (WCA) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Optimization of the phase inversion process yielded membranes with nearly complete surface coverage by PAA, even when the graft copolymer represented only 8 wt% of the membrane's composition. The hydrophilized membranes exhibited increased water flux and even pH-responsive water flow without adversely affecting their mechanical properties. In addition, these hydrophilic membranes exhibited long-term stability. Therefore, this novel binary amphiphilic graft copolymer-based approach for membrane modification may be of commercial value.
Co-reporter:Ganwei Zhang, Jiwen Hu, Guojun Liu, Hailiang Zou, Yuanyuan Tu, Fei Li, Shengyu Hu and Hongsheng Luo
Journal of Materials Chemistry A 2013 - vol. 1(Issue 20) pp:NaN6237-6237
Publication Date(Web):2013/04/02
DOI:10.1039/C3TA10722A
Random bi-functional copolymers bearing fluorinated units and sol–gel forming units were prepared and used together with silica particles in a one-pot process for preparing superamphiphobic coatings. The copolymers P(FOEA-r-IPSMA) were prepared by atom transfer radical polymerization (ATRP) of 2-(perfluorooctyl)ethyl acrylate (FOEA) and 3-(triisopropyloxy)silylpropyl methacrylate (IPSMA). The uniform silica particles were prepared using a modified Stöber process. Stirring P(FOEA-r-IPSMA), silica, water, and HCl together with substrates triggered the sol–gel reactions of the IPSMA units. These involved first the hydrolysis of IPSMA to yield silanol groups and then the condensation of the IPSMA silanol groups among themselves, and with silanol groups on silica or glass surfaces or with hydroxyl groups on cotton or filter paper. At optimized mass ratios of P(FOEA-r-IPSMA) to silica, the resultant coatings consisted of lightly covered silica particles that were embedded in a crosslinked P(FOEA-r-IPSMA) film. By optimizing the molar ratio between FOEA and IPSMA in P(FOEA-r-IPSMA), the rough particulate coatings on cotton, filter paper, and glass plates exhibited superamphiphobicity. More importantly, the particulate coatings were resistant to solvent extraction and NaOH etching.
Co-reporter:Ganwei Zhang, Jiwen Hu, Yuanyuan Tu, Guping He, Fei Li, Hailiang Zou, Shudong Lin and Gonghua Yang
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 29) pp:NaN19464-19464
Publication Date(Web):2015/06/23
DOI:10.1039/C5CP02751A
The diblock copolymer poly[2,2,2-trifluoroethyl methacrylate-r-styrene]-block-poly[(2-cinnamoyloxyethyl methacrylate)] [P(TFEMA-r-Sty)-b-PCEMA] was synthesized via atom transfer radical polymerization. The copolymer underwent self-assembly in TFEMA/CH2Cl2 to form spherical micelles. Photo-cross-linking of the PCEMA domains of these micelles yielded cross-linked nanoparticles. The cross-linked nanoparticles were subsequently cast from CH2Cl2/methanol solvent mixtures at methanol volume fractions of more than 30% to yield rough surfaces bearing small nanobumps on micron-sized aggregations that were connected together to form cross-linked nanoparticles. These surfaces were superhydrophobic with a water contact angle of 161 ± 1° and a sliding angle of 6 ± 1°. Spraying these nanoparticles onto substrates exhibiting microscale roughness, such as filter paper, by a traditional coating technique also created superhydrophobic surfaces. A thin layer of nanoscale spherical protrusions was observed on the microscale fibers of filter paper by scanning electron microscopy. The coated filter paper samples exhibited a water contact angle and a sliding angle of 153 ± 1° and 9 ± 1°, respectively.
Co-reporter:Hailiang Zou, Shudong Lin, Yuanyuan Tu, Guojun Liu, Jiwen Hu, Fei Li, Lei Miao, Ganwei Zhang, Hongsheng Luo, Feng Liu, Chengmin Hou and Meilong Hu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 37) pp:NaN11260-11260
Publication Date(Web):2013/07/17
DOI:10.1039/C3TA12224G
We report here a simple and reproducible strategy for fabricating highly durable and robust superhydrophobic cotton fabrics (SCFs) from a series of functional diblock copolymers. These diblock copolymers consisted of both poly(glycidyl methacrylate) (PGMA) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) blocks that were synthesized via sequential atom transfer radical polymerization (ATRP). While the PTFEMA block provides the low surface free energy, the PGMA block serves as an anchor and forms covalent bonds with the surfaces of cotton fibers. These covalent bonds are formed via the epoxy ring-opening reaction between the epoxy groups of the PGMA block and the hydroxyl groups on the surface of the cotton fiber, and self-crosslinking of epoxy groups from PGMA chains. Structures exhibiting nano- and microscale roughness were created in one-step by combining copolymer-based nanobumps onto surfaces of micro-sized fibers of the cotton fabric, as confirmed by SEM and AFM analysis. The modified cotton fabrics show excellent water repellency with water contact angles (WCAs) of ∼163° and water sliding angles (WSAs) of ∼3° under optimized conditions. Since the low-fluorinated PTFEMA chains are chemically bound to the cotton fibers, the SCFs possess long-term stability, ultra-high durability and robustness. In particular, these SCFs withstood mechanical abrasion by sandpaper, strong laundering conditions, ultrasonication treatment in tetrahydrofuran (THF) or trifluorotoluene (TFT), soaking in a wide range of organic solvents, as well as acidic and basic aqueous solutions, exposure to UV-irradiation and even refluxing in TFT or THF.
