TABLE OF CONTENTS

Volume 44, Issue 11 (November 2012)

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Original Articles

Polymer Synthesis and Reactions

Chiral amplification in double-stranded helical polymers through chiral and achiral amidinium–carboxylate salt bridges FREE

Wataru Makiguchi, Shinzo Kobayashi, Yoshio Furusho and Eiji Yashima

Polym J 44: 1071-1076; advance online publication, May 16, 2012; doi:10.1038/pj.2012.70

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m-Terphenyl-based random copolymers of chiral and achiral amidines and its complementary homopolymer of achiral carboxylic acids self-assembled to form complementary double helices with a preferred-handed helical sense via interstrand amidinium–carboxylate salt bridges, thus showing induced cotton effects in the π-conjugated main-chain chromophore regions. A unique amplification of the helical chirality (‘the sergeants and soldiers effect’) was, for the first time, observed during the double-helix formation.

Subject Category: Polymer Synthesis and Reactions

Preparation of 20-nm poly(styrene derivative) particles via polymerization with nonionic surfactant at the phase-inversion temperature FREE

Kiyoshi Suzuki, Kohei Nishiyama, Isao Yamanaka, Takatoshi Koshiba and Shuzaemon Satoh

Polym J 44: 1077-1081; advance online publication, May 16, 2012; doi:10.1038/pj.2012.75

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Poly(styrene derivative) particles, average diameter of which is <30nm, were prepared without ionic emulsifier with nonionic emulsifier polyoxyethylene alkyl phenyl ether by polymerizing monomer, emulsifier, water and initiator mixture at around PIT. Effects of initiator concentration, temperature and monomer type on the average diameter of the generated polymer particles are investigated. Smaller particles are obtained with higher rate of radical generation at PIT. The particles of poly(p-methylstyrene) which have an average diameter of 21nm and a polymer weight fraction of 5% were prepared.

Subject Category: Polymer Synthesis and Reactions

Iodine transfer dispersion polymerization with CHI3 and reversible chain transfer-catalyzed dispersion polymerization with N-iodosuccinimide of methyl methacrylate in supercritical carbon dioxide FREE

Tomoya Taniyama, Taisuke Kuroda, Hideto Minami and Masayoshi Okubo

Polym J 44: 1082-1086; advance online publication, May 23, 2012; doi:10.1038/pj.2012.78

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Iodine transfer dispersion polymerization (dispersion ITP) with CHI3 and reversible chain transfer-catalyzed dispersion polymerization (dispersion RTCP) with N-iodosuccimide (NIS) of methyl methacrylate (MMA) were successfully applied to supercritical carbon dioxide (scCO2) medium. Both polymerizations proceeded smoothly and yielded the polymeric product as a powder. In both systems, the number-average molecular weights increased with increasing conversion and polydispersity (Mw/Mn) was maintained at low values throughout the polymerizations. A chain extension test indicated that PMMA prepared by dispersion ITP and dispersion RTCP in scCO2 had high degrees of livingness.

Subject Category: Polymer Synthesis and Reactions

Synthesis, characterization and properties of amphiphilic block copolymers of 2-hydroxyethyl methacrylate and polydimethylsiloxane prepared by atom transfer radical polymerization FREE

Serkan Bas and Mark D Soucek

Polym J 44: 1087-1097; advance online publication, June 6, 2012; doi:10.1038/pj.2012.86

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Number of aggregations is very small when THF was used compared with methanol and methanol–water. Aggregation of copolymers was difficult in THF due to back-folding and looping of PDMS block. This was unfavorable as it increases free energy of system. This probably resulted in higher CMC of pHEMA-b-PDMS-b-pHEMA copolymers in THF than in methanol. Micellar size of most of triblock copolymers in THF was smaller than in methanol.

Subject Category: Polymer Synthesis and Reactions

Physical Properties of Polymers

Study of the rheological properties and crystallization behavior of branched PP/silicate composites FREE

Kyung Hwa Yoon, Sung Park and Youn Cheol Kim

Polym J 44: 1098-1104; advance online publication, April 25, 2012; doi:10.1038/pj.2012.68

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The slopes of G″–G′ decreased to 1.21 for the long-chain branched-polypropylene (LCB-PP) and 1.07 for PP-F07-S5. A decreased slope indicates an increase in elasticity, shear thinning effect and melt strength. The extending Avrami analysis proposed by Ozawa applied to PP, LCP-PP and the composite. The exponents were 3.6 for PP, 2.4 for LCB-PP and 1.5 for the composite.

Subject Category: Physical Properties of Polymers

Dispersion and release of embelin from electrospun, biodegradable, polymeric membranes FREE

Pablo R Cortez Tornello, Gabriela E Feresin, Alejandro Tapia, Itiara G Veiga, Ângela M Moraes, Gustavo A Abraham and Teresita R Cuadrado

Polym J 44: 1105-1111; advance online publication, May 16, 2012; doi:10.1038/pj.2012.80

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Poly(ε-caprolactone) (PCL) microfiber meshes containing embelin, a poorly water-soluble biactive agent, were prepared by electrospinning. Thermal properties revealed that the crystallinity of embelin was significatively decreased being the drug almost completely dissolved in the PCL fibers. Drug-loading content resulted appropriate for topical applications. Drug-loaded fibrous scaffolds exhibited an increase of 86% in the area-to-volume ratio and provided an effective area per unit mass that was 5.8-fold higher than that presented in drug-loaded films. This polymeric carrier would allow a better in situ bioavailability of embelin.

Subject Category: Physical Properties of Polymers

Polymer Surface and Interfaces

Preparation of hemispherical polystyrene particles utilizing the solvent evaporation method in aqueous dispersed systems FREE

Takuya Tanaka, Tomoe Yamagami, Tatsuhiro Nogami, Hideto Minami and Masayoshi Okubo

Polym J 44: 1112-1116; advance online publication, May 23, 2012; doi:10.1038/pj.2012.71

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Various nonspherical polystyrene (PS) particles were prepared by slow evaporation of toluene from homogeneous PS/hexadecane (HD)/toluene droplets dispersed in surfactant aqueous solutions at room temperature, followed by rapid removal of HD from PS/HD particles with various phase-separated morphologies. The morphology of PS/HD particles could be controlled by tuning each interfacial tension employing various types of surfactants. Consequently, hemispherical PS particles with flat surface were obtained from phase-separated PS/HD/toluene droplets having Janus structure, when Emulgen 931 was used as the surfactant.

Subject Category: Polymer Surface and Interfaces

Functional Polymers

Immobilization of acid phosphatase on a polyaniline/poly(acrylic acid) composite film for use as the anode of a fuel cell driven with L-ascorbic acid 2-phosphate FREE

Toshimasa Homma, Mizuki Kondo, Takashi Kuwahara and Masato Shimomura

Polym J 44: 1117-1122; advance online publication, May 16, 2012; doi:10.1038/pj.2012.81

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An enzyme electrode was fabricated by covalent immobilization of acid phosphatase (ACP) on a polyaniline/poly(acrylic acid) composite film for use as the anode of a fuel cell driven with L-ascorbic acid 2-phosphate (ASA2P). The enzyme electrode showed an activity in biochemical dephosphorylation of ASA2P to ascorbic acid (ASA), and succeeded in electrochemical oxidation of ASA. The ASA2P fuel cell equipped with the enzyme electrode gave a maximum power output of 6.0μWcm−2-anode, reflecting the bioelectrochemical activity of the electrode.

Subject Category: Functional Polymers

Biopolymers, Bio-related Polymer Materials

Studies on photoreactive and biodegradable copolymers composed of poly(ε-caprolactone) and 4-hydroxycinnamic acid FREE

Jihang Li, Huaqing Xu, Na Hu, Dongjian Shi, Weifu Dong, Chao Wu and Mingqing Chen

Polym J 44: 1123-1130; advance online publication, May 23, 2012; doi:10.1038/pj.2012.85

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Fluorescence emission spectra of PCL-co-P4HCA50 with UV irradiation at λ=302nm for various times, and the inset shows the fluorescent intensity changes with UV irradiation time.

Subject Category: Biopolymers, Bio-related Polymer Materials

Polymer Engineering

Preparation and characterization of organosoluble polyimide/BaTiO3 composite films with mechanical- and chemical-treated ceramic fillers FREE

Chia-Yang Lin, Dong-Hau Kuo, Fong-Ren Sie, Ju-Yin Cheng and Guey-Sheng Liou

Polym J 44: 1131-1137; advance online publication, May 16, 2012; doi:10.1038/pj.2012.79

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Our PI/BaTiO3 hybrid composites were prepared by mixing the organosoluble PI derived from one-step polymerization with BaTiO3 in dimethylacetamide, screen printing the pastes to form composite films and drying at 90°C for 24h. The low-temperature process is a key for the PI-based flexible devices to be integrated with flexible electronics. The reported PI/BaTiO3 dielectric films were prepared by a two-step process, which needed to be further imidized at 300°C.

Subject Category: Polymer Engineering

A study of the layered microstructure and electrical resistivity of an injection-molded metallic fiber-filled polymer composites FREE

Haihong Wu, Xingzhi Sun, Gangyi Cai and Zhenfeng Zhao

Polym J 44: 1138-1144; advance online publication, May 23, 2012; doi:10.1038/pj.2012.83

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Our study explored layered microstructures and the resistivity of injection stainless steel fiber-filled polymer composite. Figure 2 in this paper shows the microstructures at different layers of the molding, which was used to discuss the distribution and mass fraction of the fibers in the matrix at different layers. Based on the results of Figure 2, we discussed the effects of injection parameters on the resisitivity of each layer of the molding.

Subject Category: Polymer Engineering

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Notes

Polymer Synthesis and Reactions

End-group stannylation of regioregular poly(3-hexylthiophene)s FREE

Luozheng Zhang, Kazuhito Hashimoto and Keisuke Tajima

Polym J 44: 1145-1148; advance online publication, May 23, 2012; doi:10.1038/pj.2012.84

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Mono- and bis-stannylation at the chain ends of regioregular poly(3-hexylthiophene) (P3HT) were conducted by post-functionalization of P3HT synthesized through Ni-catalyzed Grignard metathesis polymerization. Lithiation of P3HT with s-BuLi and subsequent stannylation with Me3SnCl led to the formation of bis-stannylated P3HT. The highest conversion of 81% was achieved with the additive N,N,N′,N′-tetramethylethylenediamine (TMEDA), which could enhance the stability of the lithiated compound. On the other hand, mono-stannylated P3HT was synthesized without contamination by bis-stannylated P3HT through successive reactions with a Grignard reagent and Me3SnCl.

Subject Category: Polymer Synthesis and Reactions

Polymer Surface and Interfaces

Molecular dynamics simulations for microscopic behavior of water molecules in the vicinity of zwitterionic self-assembled monolayers FREE

Ryo Nagumo, Tatsunori Ito, Kazuki Akamatsu, Ryuji Miura, Ai Suzuki, Hideyuki Tsuboi, Nozomu Hatakeyama, Hiromitsu Takaba and Akira Miyamoto

Polym J 44: 1149-1153; advance online publication, May 9, 2012; doi:10.1038/pj.2012.72

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Microscopic behaviors of explicit water molecules on biocompatible zwitterionic self-assembled monolayer (SAM) surfaces were investigated by molecular dynamics simulations. The orientational distribution of water molecules near the surfaces was evaluated to analyze its structural properties. Consequently, water molecules on the zwitterionic SAMs are randomly oriented. In contrast, those near the surface of poly(vinyl alcohol) are highly oriented, resulting from the structured hydrogen bonding network. Microscopic properties of water molecules on the interfaces would have a key role in the suppression of protein adsorption for zwitterionic biomaterials.

Subject Category: Polymer Surface and Interfaces