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Li F.,CAS Guangzhou Institute of Chemistry | Li F.,Chinese Academy of Sciences | Li F.,University of Chinese Academy of Sciences | Li F.,Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics | And 28 more authors.
Polymer Chemistry | Year: 2015

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. © The Royal Society of Chemistry. Source


Mo Y.,CAS Guangzhou Institute of Chemistry | Mo Y.,Chinese Academy of Sciences | Mo Y.,University of Chinese Academy of Sciences | Mo Y.,Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics | And 20 more authors.
RSC Advances | Year: 2016

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. © 2016 The Royal Society of Chemistry. Source


Hu S.,CAS Guangzhou Institute of Chemistry | Hu S.,University of Chinese Academy of Sciences | Hu S.,Chinese Academy of Sciences | Hu S.,Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics | And 27 more authors.
Journal of Materials Chemistry A | Year: 2016

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. © 2016 The Royal Society of Chemistry. Source


Miao L.,Foshan University | Miao L.,CAS Guangzhou Institute of Chemistry | Miao L.,Chinese Academy of Sciences | Miao L.,Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics | And 22 more authors.
Carbohydrate Polymers | Year: 2016

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. © 2015 Elsevier Ltd. All rights reserved. Source


Zhang G.,Huanggang Normal University | Zhang G.,CAS Guangzhou Institute of Chemistry | Zhang G.,Chinese Academy of Sciences | Zhang G.,Guangdong Provincial Key Laboratory of Organic Polymer Materials for Electronics | And 21 more authors.
Physical Chemistry Chemical Physics | Year: 2015

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. This journal is © the Owner Societies. Source

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