Journal of Polymer Science Part A: Polymer Chemistry

Surface-initiated ATRP was applied for the step-by-step growth of the biomimetic amphiphilic block copolymer membrane on a gold support. Different thicknesses of membranes were achieved through the variation of the polymerization conditions. The OH-groups of the hydrophilic polymer blocks can be further functionalized to tune the membrane properties. Synthesis, characterization, and solvent-responsive properties of the amphiphilic triblock copolymer membrane are presented. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com]

Thiol-ene-acrylate ternary systems involve simultaneous photopolymerization of a multifunctional thiol, multifunctional ene, and multifunctional acrylate. In contrast, thiol-ene networks based on oligomeric thiols utilize an amine-catalyzed Michael reaction between multifunctional thiols and multifunctional acrylates. These oligomeric thiols are then copolymerized with a multifunctional ene to form a network with the same chemical components as the ternary network but with a different glass transition temperature.

Synthesis of poly(acrylonitrile-co-methyl methacrylate-co-methyl acrylate) with controlled molecular weight and low polydispersity was carried out using atom transfer radical polymerization conditions. The stereosequence analysis of synthesized terpolymers was performed with the help of 2D HSQC and TOCSY spectra. Complex and overlapped region in ¹H and ¹³C{¹H} NMR spectra were resolved completely to different configurational and compositional sequences.

Novel segmented polyurea elastomers containing hydrolytically/oxidatively stable soft polyisobutylene (PIB) segments were synthesized and characterized. The hydrolytic/oxidative stability of PIB-based polyureas is unprecedented. Upon exposure to boiling water or concentrated nitric acid, PIB-based polyureas survived without much degradation. We hypothesize that the vulnerable hard urea segments are shielded by the continuous inert soft PIB matrix. Rubbery PIB-based polyureas exhibit combinations of mechanical properties suitable for biomedical applications. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

The use of automated synthesizers in materials research has received much attention, but several challenges, including toxic chemical handling and the accuracy of liquid and solid dispensing, have not been thoroughly addressed. This article explores the advantages and challenges of using automated polymer synthesis. Automated synthesis procedures for carbodiimide-mediated polyesterification, phosgenation of diphenols, free radical, and reversible addition-fragmentation chain-transfer (RAFT) polymerizations are investigated and evaluated relative to manual ones.

H-shaped terpolymers composed of PtBA as the main chain, PS and PEO as the side chains were successfully synthesized through ATRC reaction. The moderate coupling efficiency for the formation of H-shaped ABCAB terpolymer was obtained. The increase of the coupling temperature is favorable to improve the coupling efficiency, but the ideal reaction temperature is 90 °C. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Methyl methacrylate/tert-butyl methacrylate gradient copolymers having linear and hyperbolic composition profiles were synthesized via a model-based computer-controlled semi-batch atom transfer radical copolymerization (ATRcoP) process.

Core-shell type hyperbranched polymers that can form unimolecular micelles and reverse micelles, in aqueous and hydrocarbon medium, respectively, were synthesized via two approaches, namely AB₂ + A-R and A₂ + B₃ + A-R type copolymerizations. Dye-uptake measurements revealed that the polymers prepared via AB₂ + A-R approach exhibited a significantly larger uptake compared with those prepared via the A₂ + B₃ + A-R approach, suggesting that the later approach yields polymers with significantly lower branching levels, which form less compact structures. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Novel thermoresponsive copolymers with well-controlled shapes and structures, that is, linear PAN-b-PNIPAM, comb-like PAN-co-(PHEMA-g-PNIPAM), and PAN-b-(PHEMA-g-PNIPAM), were synthesized by a combination of RAFT polymerization and ATRP. The temperature-dependence of surface wettability is obviously affected by the copolymer shapes and the length of PNIPAM block. These thermoresponsive copolymers are latent materials for functional fibers and membranes. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Cationic air- and moisture-stable palladium(II) phosphine carboxylate complexes are proven to be exceedingly active and latent catalysts for addition polymerization of norbornene; preliminary studies have implicated cationic “Pd-H” species as the catalytically active species responsible for norbornene polymerization.

A series of modified thiophene groups containing PPV-based polymers has been synthesized through a Horner coupling reaction. The polymers were designed to possess different rigid thiophene groups in polymer backbones. The physical and optical properties of the polymers were carefully characterized. Studies of the atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis of the polymer thin films revealed that all the polymers were amorphous structure. Field-effect transistors (FET) exhibit that the relatively rigid polymer, PPTVT gave better FET device performance, which depend on the elongation of conjugation length and better π–π stacking of polymer chains in amorphous region. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Commercially available poly(VDF-co-HFP) copolymers are grafted with a novel amine bearing para-sulfonic acid aromatic group. The grafting mechanism includes first a dehydrofluorination of the fluorinated backbone, then the addition of the amine onto dehydrofluorinated macromolecules, and finally a rearrangement leading to an imine.

The photophysical and electrochemical properties and photovoltaic performance of two novel series of multi-triarylamine-substituted carbazole-based dendrimers G₂-OTP(n)-G₂ (n = 6–8) and G₂-OT(n)BTD-G₂ (n = 2, 4, 6) showed a strong dependence on the chemical structures and conjugation length of the oligothiophene core.

Copolymers PFG1∼PFG4 containing 0.006–0.5 mol % 2,5-dihexyloxy-1,4-bis(2-phenyl-2-cyanovinyl)benzene (chromophore) were synthesized as blue and green emitting hosts. The chromophores act as charge trapping sites due to its narrow band gap (ca. 2.56 eV). The performance of their EL devices was improved (2080 cd/m2 → 6790 cd/m2) with increased chromophore content. In addition, white EL device was fabricated using blend of PFG2 and red phosphor Ir(piq)2(acac) as emitting layer, with maximum brightness and CIE coordinate were 4120 cd/m2 and (0.31, 0.28), respectively.

Ring-opening copolymerization of L-lactide (LA) and novel cyclic carbonate monomer 5-methyl-5-cinnamoyloxymethyl-1,3-dioxan-2-one (MC) containing a cinnamate moiety leads to a random copolymer P(LA-co-MC). The UV irradiation-induced photo-crosslinking of the pendant cinnamate moiety was investigated by exposing it to a UV light of 365 nm. This approach can be adapted to other chromophores displaying photoreactivity and other aliphatic polyesters that are promising for cell or tissue engineering applications.

The usefulness of all commercial lanthanide triflates as catalysts for polycondensations of aliphatic diols and dicarboxylic acids was evaluated.

Two types of multiarm star block copolymers: (polystyrene)_m-poly(divinylbenzene)-poly(methyl methacrylate)_n, (PS)_m-polyDVB-(PMMA)_n and (polystyrene)_m-poly(divinylbenzene)-poly(tert-butyl acrylate)_k, (PS)_m-polyDVB-(PtBA)_k were successfully prepared via a combination of cross-linking and Diels–Alder click reactions based on “arm-first” methodology. For this purpose, multiarm star polymer with anthracene functionality as reactive periphery groups was prepared by a cross-linking reaction of divinyl benzene using α-anthracene end functionalized polystyrene (PS-Anth) as a macroinitiator. Thus, obtained multiarm star polymer was then reacted with furan protected maleimide-end functionalized polymers: PMMA-MI or PtBA-MI at reflux temperature of toluene for 48 h resulting in the corresponding multiarm star block copolymers via Diels–Alder click reaction. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com]

A series of polyacrylates containing a different number of 1H-1,2,3-triazole pendants have been successfully synthesized via conventional free radical polymerization. Proton conductivity measurements were made using impedance spectroscopy. Introduction of more than one triazole per repeat unit did not result in an increase in conductivity as it was offset by the accompanying increase in T_g.

ATRP-synthesized polystyrene-b-poly(4-vinylbenzoic acid) block copolymers can self-assemble in toluene to form micelle-like nanoparticles. The reactive micelles, generated after addition of TMA, can be used as organic supports for iron catalyst in ethylene polymerization. They enable the production of polyethylene beads with a spherical morphology. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com]

A nearly monochromatic red electroluminescent nonconjugated polymer containing carbazole segments and phenanthroline [Eu(β-diketonate)₃] moieties was synthesized via free radical copolymerization, fully characterized, and incorporated into light emitting diodes as emitting layer. The design-cum-synthesis approach allows promising molecular architecture to realize efficient red LEDs based on Eu-chelated polymers. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

A fluorescent hyperbranched copolymer (HTP) and a linear copolymer (PTP) as a reference sample to HTP, both containing triphenylamine and divinyl bipyridyl units, were synthesized via Heck coupling reaction from 5,5′-Divinyl-2,2′-bipyridyl with tris(4-bromophenyl)amine and with 4,4′-dibromotriphenylamie, respectively. The spectroscopic results of HTP and PTP indicated that hyperbranched conjugated structure increases the effective conjugation length, as compared with corresponding linear conjugated structure. The quenching effect of HTP is more sensitive toward transition metal than linear copolymer PTP.

Biodegradable, hyperbranched polyesters were prepared by polycondensation of 1,1,1-tris(hydroxymethyl) ethane and dimethyl esters of aliphatic dicarboxylic acid using new bismuth-based catalysts. These Bi-catalysts combine two advantages: low toxicity and fewer side reactions.

Dibenzofulvene (DBF), which is known to afford a polymer having π-stacked conformation, was polymerized anionically using potassium menthoxide synthesized from (−)-menthol and KH as initiator. The obtained polymer having a chiral menthoxy group at the terminal was optically active and indicated circular dichroism (CD) absorption bands in the absorption wavelength range of fluorenyl group, indicating that a single-handed helical conformation was induced to the π-stacked chain by the influence of the terminal group. Theoretical CD calculation indicated that the polymer has a left-handed helical conformation.

Novel aliphatic copolyesters, fully based on renewable resources, are synthesized by ring opening polymerisation of two cyclic monomers derived from plant carbohydrates, L-lactide from starch fermentation and a hydroxylactone ((1R,5S)-1-hydroxy-3,6-dioxabicyclo [3.2.1] octan-2-one) from cellulose pyrolysis. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

2-Dicyclohexyl- and 2-diphenylphosphinophenol, CCHH and PPHH, react with Ni(1,5-COD)₂ to form catalysts for polymerization of ethylene in or copolymerization with α-olefins. The more P-basic CCHH/Ni catalyst allows concentration-dependent incorporation of olefins to give copolymers with isolated side groups, whereas the PPHH/Ni catalyst undergoes only stabilizing interactions with most olefins and leads to oligomers with no or marginal olefin incorporation.

Styrene/PEGylated–fluoroalkyl styrene block copolymers were synthesized by ATRP. The surface microphase structure in thin films of the copolymers was investigated using grazing incidence small angle X-ray scattering (GISAXS). It was found that diverse surface morphologies could be created by the macromolecular engineering of the block copolymers. The Figure shows 2-dimensional GISAXS images of the lamellar morphology of block copolymer S51Sz6 at X-ray incidence angles α_i below (a) and above (b) the critical incidence angle. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

A series of triphenylamine-based polymers containing electron-donating methoxy (OCH₃) and electron-withdrawing cyano or nitro (CN or NO₂) substituents in the main chains have been designed and studied. These conjugated polymers (P1–P3) could be readily prepared by oxidative coupling polymerization from monomers (M1-M3) using FeCl₃ as an oxidant. The P2 and P3 exhibited moderate high T_g values (203–205 °C) and thermal stability. These polymers in NMP solution showed UV–vis absorption around 288–404 nm and photoluminescence peaks around 435–492 nm. P1–P3 showed reversible oxidation redox couples at E_onset = 0.67, 0.99, and 1.00 V in solution of 0.1 M tetrabutylammonium perchlorate (TBAP)/acetonitrile (CH₃CN), respectively. M3 and P3 also exhibited reversible reduction redox couples at E_onset = −1.04 and −1.03 V. These polymers also revealed electrochromic characteristic changing color at different potential. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Polytransesterification reaction carried out to obtain a high-molecular weight poly(ethylene 2,5-furandicarboxilate) with a regular structure and high degree of crystallinity.

This article deals with the end-group functionalization of ROM-polymers using acrylates. After preparation of the corresponding (block co-)polymers with (H₂IMes)(pyridine)₂RuCl₂(=CHPh) as the initiator acrylates were added to the reaction mixture and functionalization of one terminus of the polymer was achieved.

A new method for immobilizing horseradish peroxidase (HRP) in the enzymatic synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) is reported. This method is based on 3,4-ethylenedioxythiophene monomer droplets created due to its poor solubility in water and in the stabilization effect that these monomer droplets show on the enzyme activity. A biphasic catalytic system is created where the enzyme is encapsulated inside the monomer phase and the other components such as H₂O₂ oxidant and poly(sodium 4-styrenesulphonate) (PSS) template are in the aqueous phase. After reaction the remaining EDOT/HRP phase is easily recovered and reused several times showing highly reproducible conjugation lengths as well as electrical conductivity values of 2.10⁻³ S/cm. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

To enable gene transcription or lac operon transcription, isopropyl β-D-thiogalactoside (IPTG) and allolactose can bind to the lac repressor. New S-glycodendrimers for activation of the lac operon were synthesized by S-glycosidation and DCC-HOBt coupling with a poly(amidoamine) dendrimer. Expression of artificial protein was performed for Escherichia coli using these glycodendrimers as the inducers. Cells encoded with green fluorescent protein (GFP) were induced with the glycoconjugates. After expression at 37 °C for 4 h, fluorescence emissions were actually observed through visual observation, which indicated that S-glycodendrimer acted as an inducer for protein biosynthesis. Quantitative analysis using fluorescence spectrometer was carried out to evaluate the activity. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

PMMA samples were prepared with different free radical initiators, and it was found that samples from tert-butyloxy radicals have a higher T_g. The viscosity–molecular weight study showed that the PMMA with lower T_g has higher viscosity than that of the PMMA with higher T_g when they have the same molecular weight. This indicated that when MMA is polymerized with tert-butyloxy radicals some branched polymers were produced, which resulted in the decreased segmental mobility of the polymer chain and an increased T_g.