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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.

A 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

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.

In this study, an environmentally friendly biosorbent deacetylated konjac glucomannan conjugated soy protein isolate (abbreviated as DKGM-C-SPI) was prepared for Cu(2+) ions removal from aqueous solution. Scanning electron microscopy, Fourier transform infrared spectroscopy and zeta potential analysis revealed successful conjugation of soy protein isolate (SPI) onto deacetylated konjac glucomannan (DKGM) matrix. A comparative adsorption performance of DKGM-C-SPI and DKGM was tested to remove Cu(2+) ions from aqueous solution. DKGM-C-SPI showed the desired adsorption performance for Cu(2+) ions. The adsorption equilibrium of DKGM-C-SPI was achieved within 30 min. The adsorption behavior of DKGM-C-SPI followed a pseudo-second-order reaction model. The maximum Cu(2+) ion adsorption capacities obtained from the Langmuir isotherms fit were shown to be 62.50 mg g(-1) for DKGM-C-SPI and 12.23 mg g(-1) for DKGM. This impressive increase about 5 times in Cu(2+) ion adsorption capacity is attributed to the strong Cu(2+) ion chelating ability of the soy protein isolate (SPI) on the DKGM matrix. These results confirm that the DKGM-C-SPI biosorbent has a potential for Cu(2+) ion extraction from wastewater.

Soy protein isolate (abbreviated as SPI) was chemically immobilized on deacetylated konjac glucomannan (abbreviated as DKGM) in the current work. The obtained porous SPI/DKGM composite beads were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR) and zeta potential analysis. Adsorption performances of porous SPI/DKGM composite beads were tested to remove methylene blue from aqueous solution. Benefiting from the combined merits of SPI, high adsorption capacity and fast adsorption of methylene blue (MB) by porous SPI/DKGM composite beads are achieved. The maximum methylene blue adsorption capacities were shown to be 272.4 mg g −1 for porous SPI–DKGM composite beads. These results confirm that the porous SPI–DKGM composite beads have a potential for methylene blue removal from wastewater.

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.

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.

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.

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.

Two fluorinated diblock copolymers were prepared, characterized, and used to coat cotton fabrics. These copolymers included poly[2-(perfluorohexyl)ethyl acrylate]-block-poly[(triisopropyloxysilyl)propyl methacrylate] (PFHEA-b-PIPSMA) and poly[2-(perfluorohexyl)ethyl acrylate]-block-poly(glycidyl methacrylate) (PFHEA-b-PGMA). The PFHEA block provided the coatings with a low surface tension to help impart water-repellency, while the PIPSMA or PGMA blocks (bearing alkoxysilane or epoxide groups, respectively) allowed the anchoring of the copolymers onto the cotton fibers. A simple coating procedure was used to yield water-repellent cotton fabrics. Water contact angles were measured to evaluate the durability of the treated cotton fabrics after they had been subjected to extraction, washing and laundry tests. These results revealed that cotton fabrics coated with PFHEA-b-PIPSMA were rendered hydrophobic, but their stability was relatively poor. Meanwhile, cotton fabrics coated with PFHEA-b-PGMA exhibited water contact angles higher than 150° and retained their water-repellency even under harsh test conditions.

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 resul...

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°.

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-...

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 Cu 2+ of CuCl 2 at 70 °C. Cu 2+ complexation was confirmed by a conductivity reduction of CuCl 2 after amylose addition. Also, the aggregation state of the amylose changed after Cu 2+ as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). At the Cu 2+ 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 CuS 2 O 3 . At r = 0.70 and 1.41, CuS 2 O 3 precipitated inside the template of Cu 2+ /amylose microspheres as nanoparticles, while a twisted nanowire-like structure was produced at r = 0.92. CuS 2 O 3 decomposed under heating at 100 °C to yield crystalline CuS nanoparticles.

Facing the challenge of environmental degradation in China, a growing number of firms have begun to integrate environmental management systems into their business strategies and develop green innovation strategies. Based on the stakeholder theory, this paper attempts to explore the influences of stakeholders on the implementation of green process and green product innovation. Empirical results show that foreign customers play a significant role in driving companies to adopt strategy of green process and green product innovation. For foreign-invested enterprises, the effect is limited to the adoption of green process innovation. It further reveals that community stakeholders and regulatory stakeholders have no significant effect on the corporate green process and green product innovation. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.

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 (Me 6 TREN) as representatives for di-, tri-, and tetradentate amine ligands, respectively. The ATRP was better controlled, yielding polymers with controlled molecular weights and low polydispersities ( M w / M n 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 Me 6 TREN 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.

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.

In the paper, We will mainly discuss the individualism and collectivism transition in Chinese college students. We select the data from three groups-after 70’s, after 80’s, after 90’s. Then we use the empirical modeling method, after hypothesis & testing, we got the results: (1) In general, Chinese college students are still collectivistic. (2) On the time latitude, the degree of Chinese college students’ collectivism reduced, individualism increased. (3) On the spatial latitude, the object groups of Chinese college students’ collectivism changed, gradually expand from the group of relatives to the society. (4)Within the organization, collectivism changed from vertical to horizontal.