Antifouling poly(vinylidene fluoride) ultrafiltration membranes containing amphiphilic comb polymer additive

An amphiphilic comb polymer consisting of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) [P(VDF‐co‐CTFE)] main chains and poly(oxyethylene methacrylate) (POEM) side chains was synthesized using direct initiation of the chlorine atoms in CTFE units through atom transfer radical polymerization, as confirmed by ¹H NMR and FTIR spectroscopy. The P(VDF‐co‐CTFE)‐g‐POEM comb polymer was introduced as an additive to prepare poly(vinylidene fluoride) antifouling ultrafiltration membranes. As the contents of comb polymer increased, the mechanical properties of membranes slightly decreased due to the decreased crystallinity of the membranes, as revealed by universal testing machine and X‐ray diffraction. However, water contact angle measurement and X‐ray photoelectron spectroscopy showed that the hydrophilic POEM segments spontaneously segregated on the membrane surfaces. As a result, the antifouling property of the membranes containing P(VDF‐co‐CTFE)‐g‐POEM comb polymer was considerably improved with a slight change of water flux. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 183–189, 2010     

Selective swelling blends of block copolymers for nanoporous membranes with enhanced permeability and robustness

Block copolymers (BCPs) are important precursors to produce membranes with well‐defined porosities. However, it remains challenging to prepare robust and affordable BCP‐based membranes. In this work, cheap commodity styrene‐butadiene‐styrene (SBS) elastic triblock copolymers are mixed with polystyrene‐block‐poly (2‐vinylpyridine) (SV) block copolymers in solutions, leading to macroscopically stable blend films upon casting because of the compatibilizer effect of PS existing in both copolymers. By soaking the blend films in ethanol, the microdomains of poly(2‐vinylpyridine) are selectively swollen and cavitated upon drying, resulting in a hierarchical structure with perforated SV phases interwoven with the SBS phases. The blend membranes with 30% SBS exhibit improved water permeability and mechanical robustness due to the presence of elastic SBS compared to neat SV membranes; meanwhile, the rejections of the blend membranes remain largely unchanged. Moreover, the blend membranes exhibit a pH‐responsive function, and homoporous SV regions are obtained by pre‐aligning the SV phases. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1617–1625     

Synthesis and characterization of novel alternating fluorinated copolymers bearing oligo(ethylene oxide) side chains

The synthesis and characterization of novel poly(CTFE‐g‐oligoEO) graft copolymers [chlorotrifluoroethylene (CTFE) and ethylene oxide (EO)] are presented. First, vinyl ether monomers bearing oligo(EO) were prepared by transetherification of ω‐hydroxyoligo(EO) with ethyl vinyl ether catalyzed by a palladium complex in 70–84% yields. Two vinyl ethers of different molecular weights (three and 10 EO units) were thus obtained. Then, radical copolymerization of the above vinyl ethers with CTFE led to alternating poly(CTFE‐alt‐VE) copolymers that bore oligo(OE) side chains in satisfactory yields (65%). These original poly(CTFE‐g‐oligoEO) graft copolymers were characterized by ¹H, ¹⁹F, and ¹³C NMR spectroscopy. Their molecular weights reached 19,000 g mol^?1, and their thermal properties were investigated while their glass transition temperatures ranged between ?42 and ?36 °C. Their thermogravimetric analyses under air showed decomposition temperatures of 270 °C with 10% weight loss (T_d,10%). These novel copolymers are of potential interest as polymer electrolytes in lithium ion batteries, showing room temperature conductivities ranging from 4.49 × 10^?7 to 1.45 × 10^?6 S cm^?1 for unplasticized material. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and characterization of original alternated fluorinated copolymers bearing glycidyl carbonate side groups

A vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as ¹H, ¹⁹F, and ¹³C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol^?1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (T_d,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and properties of sulfonated multiblock copoly(ether sulfone)s by a chain extender

A new series of sulfonated multiblock copoly(ether sulfone)s applicable to proton exchange membrane fuel cells was synthesized. The multiblock copolymers were synthesized by the nucleophilic aromatic substitution of hydroxyl‐terminated oligomers in the presence of highly reactive decafluorobiphenyl (DFB) as a chain extender. Because of the high reactivity of DFB, the ether–ether interchange reaction, which could lead to a randomized polymer architecture, was prevented, and multiblock copolymers with high molecular weights were easily produced. The multiblock copolymers gave tough, flexible, and transparent membranes by solution casting. The ion exchange capacity values could be easily controlled by changing the sulfonated block ratios in the copolymers. The resulting membranes demonstrated good oxidative and dimensional stability and significantly higher proton conductivity than sulfonated random poly(ether sulfone) copolymers. The morphologies of the membranes were investigated by tapping mode atomic force microscopy, which showed that the multiblock membranes had a clear hydrophilic/hydrophobic separated structure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3947–3957, 2008     

Tailoring poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) microstructure and physicochemical properties by exploring its binary phase diagram with dimethylformamide

Poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) (PVDF‐CTFE) membranes were prepared by solvent casting from dimethylformamide (DMF). The preparation conditions involved a systematic variation of polymer/solvent ratio and solvent evaporation temperature. The microstructural variations of the PVDF‐CTFE membranes depend on the different regions of the PVDF‐CTFE/DMF phase diagram, explained by the Flory‐Huggins theory. The effect of the polymer/solvent ratio and solvent evaporation temperature on the morphology, degree of porosity, β phase content, degree of crystallinity, mechanical, dielectric, and piezoelectric properties of the PVDF‐CTFE polymer were evaluated. In this binary system, the porous microstructure is attributed to a spinodal decomposition of the liquid‐liquid phase separation. For a given polymer/solvent ratio, 20 wt % , and higher evaporation solvent temperature, the β phase content is around 82% and the piezoelectric coefficient, d₃₃, is ? 4 pC/N © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 761–773     

Synthesis and characterization of grafted/crosslinked proton conducting membranes based on amphiphilic PVDF copolymer

A novel graft copolymer consisting of a poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) backbone and poly(glycidyl methacrylate) side chains, that is, P(VDF‐co‐CTFE)‐g‐PGMA, was synthesized through atom transfer radical polymerization (ATRP) using CTFE units as a macroinitiator. Successful synthesis and microphase‐separated structure of the polymer were confirmed by ¹H NMR, FTIR spectroscopy, and TEM. As‐synthesized P(VDF‐co‐CTFE)‐g‐PGMA copolymer was sulfonated by sodium bisulfite, followed by thermal crosslinking with sulfosuccinic acid (SA) via the esterification to produce grafted/crosslinked polymer electrolyte membranes. The IEC values continuously increased with increasing SA content but water uptake increased with SA content up to 10 wt %, above which it decreased again as a result of competitive effect between crosslinking and hydrophilicity of membranes. At 20 wt % of SA content, the proton conductivity reached 0.057 and 0.11 S/cm at 20 and 80 °C, respectively. The grafted/crosslinked P(VDF‐co‐CTFE)‐g‐PGMA/SA membranes exhibited good mechanical properties (>400 MPa of Young's modulus) and high thermal stability (up to 300 °C), as determined by a universal testing machine (UTM) and TGA, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1110–1117, 2010     

Synthesis and characterization of multiblock partially fluorinated hydrophobic poly(arylene ether sulfone)‐hydrophilic disulfonated poly(arylene ether sulfone) copolymers for proton exchange membranes

Hydrophobic‐hydrophilic sequence multiblock copolymers, based on alternating segments of phenoxide terminated fully disulfonated poly(arylene ether sulfone) (BPS100) and fluorine‐terminated poly(arylene ether sulfone) (6FBPS0) were synthesized and evaluated for application as proton exchange membranes. By utilizing mild reaction conditions the ether–ether interchange reactions were minimized, preventing the randomization of the multiblock copolymers. Tough, ductile, transparent membranes were solution cast from the block copolymers and were characterized with regard to intrinsic viscosity, morphology, water uptake, and proton conductivity. The conductivity values of the 6FBPS0‐BPSH100 membranes were compared to Nafion 212 and a partially fluorinated sulfonated poly(arylene ether sulfone) random copolymer (6F40BP60). The nanophase separated morphology was confirmed by transmission electron microscopy and small angle X‐ray scattering, and enhanced proton conductivity at reduced relative humidity was observed with longer block lengths. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Grafting polymerization of styrene onto alternating terpolymers based on chlorotrifluoroethylene,hexafluoropropylene, and vinyl ethers,and their modification into ionomers bearing ammonium side‐groups

The grafting polymerization of styrene initiated by the alkyl chloride groups of poly(CTFE‐alt‐VE) and poly[(CTFE‐alt‐VE)‐co‐(HFP‐alt‐VE] copolymers (where CTFE, HFP, and VE stand for chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and vinyl ether (VE), respectively) followed by the chemical modification of the polystyrene grafts are presented. First, the fluorinated alternating copolymers were produced by radical copolymerization of CTFE (with HFP) and VE. Second, atom transfer radical polymerization enabled the grafting polymerization of styrene in the presence of the poly(CTFE‐alt‐VE)‐macroinitiator using the alkyl chloride group of CTFE as the initiation site. Kinetics of the styrene polymerization indicated that such a grafting had a certain controlled character. For the first time, grafting of polystyrene onto alternating fluorinated copolymers has been achieved. Differential scanning calorimetry thermograms of these graft copolymers exhibited two glass transition temperatures assigned to both amorphous domains of the polymeric fluorobackbone (ranging from ?20 to +56 °C) and the polystyrene grafts (ca. 95 °C). The thermostability of these copolymers increased on grafting. Thermal degradation temperatures at 5% weight loss were ranging from 193 to 305 °C when the polystyrene content varied from 81 to 27%. Third, chloromethylation of the polystyrene grafts followed by the cationization of the chloromethyl dangling groups led to original ammonium‐containing graft copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and characterization of partially disulfonated hydroquinone‐based poly(arylene ether sulfone)s random copolymers for application as proton exchange membranes

Partially disulfonated hydroquinone (HQ)‐based poly(arylene ether sulfone) random copolymers were synthesized and characterized for application as proton exchange membranes. The copolymer composition was varied in the degree of disulfonation. The copolymers were characterized by ¹H NMR, Differential Scanning Calorimetry (DSC), and other analytical techniques. The copolymer with a 25% degree of disulfonation showed the best balance between water uptake and proton conductivity. The copolymers showed substantially reduced methanol permeability compared with Nafion® and satisfactory direct methanol fuel cell performance. The methanol selectivity improved significantly in comparison to Nafion® 117. At a given ionic composition, the HQ‐based system showed higher water uptake and proton conductivity than the biphenol‐based (BPSH‐xx) poly(arylene ether sulfone)s copolymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 384–391, 2009     

Bis‐dendritic polyethylene prepared by ring‐opening metathesis polymerization in the presence of bis‐dendritic chain transfer agents

The synthesis of ABA triblock copolymers is described, in which the A blocks are poly(benzyl ether) dendrons and the B block is polycyclooctene or polyethylene. Bis‐dendritic cis‐olefins were synthesized and used as chain transfer agents in ring‐opening metathesis polymerization of cyclooctene in a process that inserts the dendrons at the polymer chain‐ends. Evaluation of the polymer products by spectroscopic, chromatographic, and titration methods supports their triblock structure. Hydrogenation of the unsaturated polycyclooctene B‐block of these ABA triblock copolymers provides the first reported synthesis of bisdendritic polyethylene. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5429–5439, 2005     

Dendritic poly(benzyl ether)‐b‐poly(N‐vinylcaprolactam) block copolymers: Self‐organization in aqueous media,thermoresponsiveness and biocompatibility

Four generations of new amphiphilic thermoresponsive linear‐dendritic block copolymers (LDBCs) with a linear poly(N‐vinylcaprolactam) (PNVCL) block and a dendritic poly(benzyl ether) block are synthesized by atom transfer radical polymerization (ATRP) of N‐vinylcaprolactam (NVCL) using dendritic poly(benzyl ether) chlorides as initiators. The copolymers have been characterized by ¹H NMR, FTIR, and GPC showing controlled molecular weight and narrow molecular weight distribution (PDI ≤ 1.25). Their self‐organization in aqueous media and thermoresponsive property are highly dependent on the generation of dendritic poly(benzyl ether) block. It is observed for the LDBCs that the self‐assembled morphology changes from irregularly spherical micelles, vesicles, rod‐like large compound vesicles (LCVs), to the coexistence of spherical micelles and rod‐like LCVs, as the generation of the dendritic poly(benzyl ether) increases. The results of a cytotoxicity study using an MTT assay method with L929 cells show that the LDBCs are biocompatible. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 300–308     

Comparative effect of phthalazinone units in sulfonated poly(arylene ether ether ketone ketone) copolymers as proton exchange membrane materials

A new series of aromatic poly(arylene ether ether ketone ketone) copolymers containing pendant sulfonic acid groups (SPAEEKK‐D) were synthesized from commercially available monomers 1,3‐bis(4‐fluorobenzoyl)‐benzene, sodium 6,7‐dihydroxy‐2‐naphthalenesulfonate, and 4‐(4‐hydroxyphenyl)‐2,3‐phthalazin‐1‐one (DHPZ). Structure–property relationships of the phthalazinone SPAEEKK‐D series poly(arylene ether ether ketone ketone) copolymer were compared with copolymers SPAEEKK‐B and SPAEEKK‐H containing different diols such as 4,4′‐biphenol and hydroquinone, respectively, prepared in our earlier work. Ion exchange capacity (IEC_w, weight‐based; IEC_v, volume‐based), thermal stabilities, swelling, proton and methanol transport properties of the membranes were investigated in relation to their structures and compared with those of perfluorinated ionomer (Nafion 117). The SPAEEKK‐D membrane incorporating the phthalazinone monomer DHPZ showed relatively lower water uptake and methanol permeability compared with earlier SPAEEKK‐B and SPAEEKK‐H membranes incorporating biphenol and hydroquinone monomers, respectively. Inclusion of phthalazinone in the SPAEEKK‐D copolymers led to lower water absorption, enabling increased proton exchange concentrations in the hydrated polymer matrix that resulted in more desirable membrane properties for future direct methanol fuel cell applications. The SPAEEKK‐D membranes also showed improved mechanical and thermal properties and oxidative stability compared with the earlier SPAEEKK‐B and ‐H membranes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 989–1002, 2008     

Investigation of sulfonated poly(ether ether ketone sulfone)/heteropolyacid composite membranes for high temperature fuel cell applications

The sulfonated poly(ether ether ketone sulfone) (SPEEKS)/heteropolyacid (HPA) composite membranes with different HPA content in SPEEKS copolymers matrix with different degree of sulfonation (DS) were investigated for high temperature proton exchange membrane fuel cells. Composite membranes were characterized by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR band shifts suggested that the sulfonic acid groups on the copolymer backbone strongly interact with HPA particles. SEM pictures showed that the HPA particles were uniformly distributed throughout the SPEEKS membranes matrix and particle sizes decreased with the increment of copolymers' DS. The holes were not found in SPEEKS‐4/HPA30 (consisting of 70% SPEEKS copolymers with DS = 0.8 and 30% HPA) composite membrane after composite membranes were treated with boiling water for 24 h. Thermal stabilities of the composite membranes were better than those of pure sulfonated copolymers membranes. Although the composite membranes possessed lower water uptake, it exhibited higher proton conductivity for SPEEKS‐4/HPA30 especially at high temperature (above 100 °C). Its proton conductivity linearly increased from 0.068 S/cm at 25 °C to 0.095 S/cm at 120 °C, which was higher than 0.06 S/cm of Nafion 117. In contrast, proton conductivity of pure SPEEKS‐4 membrane only increased from 0.062 S/cm at 25 °C to 0.078 S/cm at 80 °C. At 120 °C, proton conductivity decreased to poor 0.073 S/cm. The result indicated that composite membranes exhibited high proton conductivity at high temperature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1967–1978, 2006     

Synthesis and solution properties of anionic linear–dendritic block amphiphiles

The design and synthesis of novel linear–dendritic diblock amphiphiles with linear poly(acrylic acid) (PAA) as the hydrophilic block and dendritic poly(benzyl ether) as the hydrophobic block are described. The synthetic process consisted of two steps: a poly(methyl acrylate) (PMA)–poly(benzyl ether) dendrimer series were synthesized with atom transfer radical polymerization, and through the hydrolysis of linear PMA block into PAA, amphiphilic block copolymers, the PAA–poly(benzyl ether) dendrimer series, were obtained. The copolymers were characterized by ¹H NMR, Fourier transform infrared, and size exclusion chromatography and exhibited well‐defined architectures and low polydispersities. When the generation number of the dendritic block (G_i) less or equal to 3 and the degree of polymerization of the linear chain (n) was greater than 10, the amphiphiles were water‐soluble. The solution intrinsic viscosity increased with both the length of linear chain and the generation number of the dendritic block. The results obtained demonstrate that dendritic blocks play an unusual role in aqueous solutions of amphiphiles. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4282–4288, 2000     

Direct copolymerization of sulfonated poly(phthalazinone arylene ether)s for proton‐exchange‐membrane materials

Sulfonated poly(phthalazinone ether ketone) (SPPEK) copolymers and sulfonated poly(phthalazinone ether sulfone) (SPPES) copolymers containing pendant sodium sulfonate groups were prepared by direct copolymerization. The reaction of disodium 3,3′‐disulfonate‐4,4′‐difluorobenzophenone (SDFB‐Na), 4,4′‐difluorobenzophenone (DFB), and 4‐(4‐hydroxyphenyl)‐1(2H)‐phthalazinone (DHPZ) at 170 °C in N‐methyl‐2‐pyrrolidione containing anhydrous potassium carbonate gave SPPEKs. SPPESs were similarly obtained with 3,3′‐disulfonate‐4,4′‐difluorophenyl sulfone, 4‐fluorophenyl sulfone (DFS), and DHPZ as monomers. The sulfonic acid groups, being on deactivated positions of the polymer backbone, were expected to be hydrolytically more stable than postsulfonated polymers. Fourier transform infrared and ¹H NMR were used to characterize the structures and degrees of sulfonation of the sulfonated polymers. Membrane films of SPPEKs with SDFB‐Na/DFB molar feed ratios of up to 60/40 and SPPESs with sulfonated 4‐fluorophenyl sulfone/DFS molar feed ratios of up to 50/50 were cast from N,N‐dimethylacetamide polymer solutions. Membrane films in acid form were then obtained by the treatment of the sodium‐form membrane films in 2 N sulfuric acid at room temperature. An increase in the number of sulfonate groups in the copolymers resulted in an increased glass‐transition temperature and enhanced membrane hydrophilicity. The sodium‐form copolymers were thermally more stable than their acid forms. The proton conductivities of the acid‐form copolymers with sulfonated monomer/unsulfonated monomer molar feed ratios of 0.5 and 0.6 were higher than 10^?2 S/cm and increased with temperature; they were less temperature‐dependent than those of the postsulfonated products. SPPESH‐50 showed higher conductivity than the corresponding postsulfonated poly(phthalazinone ether sulfone). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2731–2742, 2003     

Effect of ammonium groups on the properties and alkaline stability of poly(arylene ether)‐based anion exchange membranes

Five kinds of ammonium groups functionalized partially fluorinated poly(arylene ether) block copolymer membranes were prepared for investigating the structure–property relationship as anion exchange membranes (AEMs). Consequently, the pyridine (PYR)‐modified membrane showed the highest alkaline and hydrazine stability in terms of the conductivity, water uptake, and dry weight. The chloromethylated precursor block copolymers were reacted with amines, such as trimethylamine, N‐butyldimethylamine, 1‐methylimidazole, 1,2‐dimethylimidazole, and PYR to provide the target quaternized poly(arylene ether)s. The structures of the polymers, as well as model compounds and oligomers were well characterized by ¹H NMR spectra. The obtained AEMs were subjected to water uptake and hydroxide ion conductivity measurements and stabilities in aqueous alkaline and hydrazine media. The pyridinium‐functionalized quaternized polymers membrane showed the highest alkaline and hydrazine stability with minor losses in the conductivity, water uptake, and dry weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 383–389     

Synthesis of poly(vinyl ether)‐based,ABA triblock‐type thermoplastic elastomers with functionalized soft segments and their gas permeability

The ABA‐type triblock copolymers consisting of poly(2‐adamantyl vinyl ether) [poly(2‐AdVE)] as outer hard segments and poly(6‐acetoxyhexyl vinyl ether) [poly(AcHVE)], poly(6‐hydroxyhexyl vinyl ether) [poly(HHVE)], or poly(2‐(2‐methoxyethoxy)ethyl vinyl ether) [poly(MOEOVE)] as inner soft segments were synthesized by sequential living cationic polymerization. Despite the presence of polar functional groups such as ester, hydroxyl, and oxyethylene units in their soft segments, the block copolymers formed elastomeric films. The thermal and mechanical properties and morphology of the block copolymers showed that the two polymer segments of these triblock copolymers were segregated into microphase‐separated structure. Effect of the functional groups in the soft segments on gas permeability was investigated as one of the characteristics of the new functional thermoplastic elastomers composed solely of poly(vinyl ether) backbones. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1114–1124     

Thermoresponsive PPEGMEA‐g‐PPEGEEMA well‐defined double hydrophilic graft copolymer synthesized by successive SET‐LRP and ATRP

A series of well‐defined double hydrophilic graft copolymers containing poly[poly(ethylene glycol) methyl ether acrylate] (PPEGMEA) backbone and poly[poly(ethylene glycol) ethyl ether methacrylate] (PPEGEEMA) side chains were synthesized by the combination of single electron transfer‐living radical polymerization (SET‐LRP) and atom transfer radical polymerization (ATRP). The backbone was first prepared by SET‐LRP of poly(ethylene glycol) methyl ether acrylate macromonomer using CuBr/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained comb copolymer was treated with lithium diisopropylamide and 2‐bromoisobutyryl bromide to give PPEGMEA‐Br macroinitiator. Finally, PPEGMEA‐g‐PPEGEEMA graft copolymers were synthesized by ATRP of poly(ethylene glycol) ethyl ether methacrylate macromonomer using PPEGMEA‐Br macroinitiator via the grafting‐from route. The molecular weights of both the backbone and the side chains were controllable and the molecular weight distributions kept narrow (M_w/M_n ≤ 1.20). This kind of double hydrophilic copolymer was found to be stimuli‐responsive to both temperature and ion (0.3 M Cl^? and SO). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 647–655, 2010     

Composite ultrafiltration membranes with tunable properties based on a self‐assembling block copolymer/homopolymer system

Composite ultrafiltration membranes were fabricated by coating a thin film of self‐assembling polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) block copolymers and poly(acrylic acid) homopolymers on top of a support membrane. Block copolymers self‐assembled into a nanostructure where the minority component forms cylinders, whereas homopolymers reside in the core of the cylinders. Selective removal of the homopolymers led to the formation of pores. The morphology of the polymer layer was controlled by varying the content of homopolymers or polymer concentration of the coating solution, which led to membranes with different molecular weight cutoffs (MWCOs) and permeabilities. Uniform pores were obtained using low homopolymer contents, whereas high homopolymer contents caused macrophase separation and resulted in large polydisperse pores or craters at the surface. The thickness of the block copolymer film also influenced the structure and performance of the membranes, where a thicker film results in a strong decrease in permeability but a lower MWCO. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1546–1558