Journal of Polymer Science Part A: Polymer Chemistry

Cover image for Vol. 51 Issue 7

1 April 2013

Volume 51, Issue 7

Pages i–iv, 1475–1683

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Highlight
    4. Rapid Communication
    5. Articles
    1. You have free access to this content
      Cover Image, Volume 51, Issue 7 (pages i–ii)

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/pola.26633

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      On page 1533, Adam B. Braunschweig and colleagues investigate the suitability of different polymer compositions of tip arrays for polymer pen lithography (PPL), and the mandala of tip arrays represents the nearly limitless number of polymer combinations that could be suitable for PPL printing. In the center is an optical microscopy image of a pen array, with the chemical structures of different polymers (polydimethylsiloxane, poly(methyl methacrylate), poly([methyl methacrylate]-co-[butyl methacrylate]), and poly(3-mercaptopropylmethylsiloxane)) that were explored to generate the pen arrays. In the corners of the mandala are scanning electron micrographs of pyramidal tips within these arrays. The mandala is superimposed on images and graphs that represent the time- and force-dependent printing that are the hallmarks of this powerful nanolithography technique.

    2. You have free access to this content
      Inside Cover, Volume 51, Issue 7 (pages iii–iv)

      Version of Record online: 27 FEB 2013 | DOI: 10.1002/pola.26634

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      Research in polymer science and engineering is moving from classical methodologies to advanced analytical strategies in which mass spectrometry (MS)-based techniques play a crucial role. The molecular complexity of polymers requires new characterization tools and approaches to elucidate the detailed structural information. In the work by Ulrich S. Schubert and colleagues on page 1595, a comparison study using different tandem MS techniques (ESI, APCI, and MALDI MS/MS) is reported to provide insights into the macromolecular structure of polymers with the aid of a special MS/MS data interpretation software. The application of a tailor-made software is shown to analyze complex MS/MS data, and it is shown that this kind of software will be helpful for polymer scientists to identify fragmentation products obtained by tandem MS, for instance in the fields of proteomics, metabolomics, genomics, and glycomics.

  2. Highlight

    1. Top of page
    2. Cover Image
    3. Highlight
    4. Rapid Communication
    5. Articles
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      Soft ionization mass spectroscopy: Insights into the polymerization mechanism (pages 1475–1505)

      Alexander H. Soeriyadi, Michael R.Whittaker, Cyrille Boyer and Thomas P. Davis

      Version of Record online: 21 JAN 2013 | DOI: 10.1002/pola.26536

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      Soft ionization mass spectroscopy is a powerful technique for characterizing polymer structures. A brief description of the different spectrometric techniques available for polymer analyses, including MALDI-TOF, ESI-MS, and other recent methods, is given. The techniques are compared and the limitations and advantages are discussed. The possible side reactions that can occur during MALDI-TOF analysis are detailed and the importance of correct sample preparation is emphasized. ESI-MS is also given attention and emphasis is placed on the limitations and optimization of samples for successful analyses.

  3. Rapid Communication

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    4. Rapid Communication
    5. Articles
    1. Photovoltaics of donor–acceptor polymers based on benzodithiophene with lateral thiophenyl and fluorinated benzothiadiazole (pages 1506–1511)

      Feiyan Wu, Daijun Zha, Lie Chen and Yiwang Chen

      Version of Record online: 21 JAN 2013 | DOI: 10.1002/pola.26545

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      A low band gap alternative polymer was synthesized. The polymer contained benzodithiophenes with lateral thiophenes and fluorinated benzothiadiazole. The polymer possessed broad absorption and high Voc. The PCE of the device with PC61BM achieved 4.8% without annealing and additive.

  4. Articles

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    3. Highlight
    4. Rapid Communication
    5. Articles
    1. Photovoltaic performance enhancement using fluorene-based copolymers containing pyrene units (pages 1512–1519)

      Chang Eun Song, In-Nam Kang, Ji-Hoon Kim, Do-Hoon Hwang, Jong-Cheol Lee, Taek Ahn, Won Suk Shin, Sang-Jin Moon and Sang Kyu Lee

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26525

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      A series of polyfluorene-based copolymers with pyrene units have been synthesized and characterized for use in polymer solar cells. Under optimized conditions, the polymers display PCEs for the PSCs in the range 1.99–3.37% under AM 1.5 illumination (100 mW cm−2). The PCEs of polymer solar cells are improved from 2.11% for devices prepared without pyrene to 3.37% for devices prepared with pyrene.

    2. Synthesis and structural characterization of a nickel(II) precatalyst bearing a β-triketimine ligand and study of its ethylene polymerization performance using response surface methods (pages 1520–1532)

      Nona Ghasemi Hamedani, Hassan Arabi, Gholam Hossein Zohuri, Francis S. Mair and Andrew Jolleys

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26522

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      In this contribution, the synthesis of a β-triketimine ligand ({2,4,6-CH3C6H2NC(CH3)}3CH) and its Ni complex has been reported as a catalyst precursor for ethylene polymerization. Response surface method (RSM) has been applied successfully for investigation of operational conditions; it provides predictive models for activity, weight-average molecular weight (Mw), and crystallinity with adequate goodness-of-fit. It also provides operational conditions for reaching user-defined values of activity, Mw, and crystallinity. The resultant activities challenge the best achieved with nickel bearing β-diimine-derived ligands.

    3. Spotlight Article

      Materials for the preparation of polymer pen lithography tip arrays and a comparison of their printing properties (pages 1533–1539)

      Xiao Zhong, Nevette A. Bailey, Kevin B. Schesing, Shudan Bian, Luis M. Campos and Adam B. Braunschweig

      Version of Record online: 26 DEC 2012 | DOI: 10.1002/pola.26513

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      Tip-arrays for polymer pen lithography (PPL) were prepared from poly(dimethyl siloxane), poly(methyl methacrylate), poly([methyl methacrylate]-co-[butyl methacrylate]), and poly(3-mercaptopropylmethylsiloxane) to explore the role of polymer mechanical properties on the force-dependent ink transfer. Ink was transferred successfully for all materials except poly([methyl methacrylate]-co-[butyl methacrylate]), and it was foundthat the relationship between force and feature edge length is governed by the mechanical properties of the polymers that comprise the tip-arrays.

    4. Titanium(IV) nonmetallocene complex catalyzed aqueous homopolymerization and copolymerization of styrene and methyl methacrylate: An Environmentally friendly approach to ultrahigh molecular weight polymer nanoparticles (pages 1540–1549)

      Sudip K. De and Manish Bhattacharjee

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26520

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      A new titanium complex bearing an asymmetric ligand has been synthesized and characterized. This complex has been found to catalyze aqueous homopolymerization and copolymerization of MMA and styrene at room temperature to afford polymer nanoparticles. The polymers obtained are of very high molecular weights.

    5. Perylene diimide copolymers with dithienothiophene and dithienopyrrole: Use in n-channel and ambipolar field-effect transistors (pages 1550–1558)

      Shiming Zhang, Yugeng Wen, Weiyi Zhou, Yunlong Guo, Lanchao Ma, Xingang Zhao, Zhen Zhao, Stephen Barlow, Seth R. Marder, Yunqi Liu and Xiaowei Zhan

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26521

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      Electron-transporting or ambipolar solution-processable polymers consisting of perylene diimide (PDI) acceptor moieties alternating with dithienothiophene (DTT), N-dodecyl-dithienopyrrole (DTP), or oligomers of these donor groups have been synthesized. In addition to varying the donor, the N,N′ substiuents of the PDIs have also been varied. The thermal, optical, electrochemical, and charge-transport properties of the polymers have been investigated. There is considerable variation in the charge transport properties of the polymers with the chemical structures.

    6. In situ Cu(0)-mediated single electron transfer living radical polymerization of methyl methacrylate using nickel powder (pages 1559–1564)

      Xiao-Hui Liu, Yun-Hai Yu, Di Jia, Bo-Wen Cheng, Fei-Jun Zhang, Hui-Na Li, Peng Chen and Shan Xie

      Version of Record online: 7 JAN 2013 | DOI: 10.1002/pola.26524

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      Single electron transfer living radical polymerization of methyl methacrylate catalyzed by the in situ prepared Cu(0) at ambient temperature was first examined using various metallic powders, including Zn(0), Ni(0), Mg(0), and Fe(0). The polymerization initiated with the Ni(0)/EBiB/CuBr2/PMDETA system exhibited optimal living/controlled nature and generated polymers with PDI as low as 1.04 for 75.27% conversion and controlled molecular weights close to theoretical values. A wide of range of Cu(II) salts were also investigated as catalyst sources instead of CuBr2. The recycling of Ni(0) was very convenient due to its magnetic property, which enables its extensive application.

    7. Donor–acceptor (donor) polymers with differently conjugated side groups at the acceptor units for photovoltaics (pages 1565–1572)

      Hongmei Qin, Lisheng Li, Tianxiang Liang, Xiaobin Peng, Junbiao Peng and Yong Cao

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26526

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      Four D-A polymers with the same main chain based on benzodithiophene and quinoxaline but with differently conjugated donor groups at the acceptor units are synthesized to investigate the impact of the conjugated side chains at the acceptor units on the photovoltaic properties of D-A polymers. The performance of the solar cells increases when thienyl or phenylene thienyl groups are used, but decreases when additional thienyl groups are added at the side chains.

    8. Dispersion RAFT polymerization of 4-vinylpyridine in toluene mediated with the macro-RAFT agent of polystyrene dithiobenzoate: Effect of the macro-RAFT agent chain length and growth of the block copolymer nano-objects (pages 1573–1584)

      Meihan Dan, Fei Huo, Xu Zhang, Xiaohui Wang and Wangqing Zhang

      Version of Record online: 5 JAN 2013 | DOI: 10.1002/pola.26527

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      The dispersion RAFT polymerization of 4-vinylpyridine in toluene in the presence of the polystyrene dithiobenzoate (PS-CTA) macro-RAFT agent with different chain lengths is discussed. It is found that that the PS-CTA chain length exerts a great influence on the polymerization kinetics, the particle nucleation and the particle morphology of the synthesized block copolymers. That is, short PS-CTA generally leads to fast RAFT polymerization and fast particle nucleation, and tends to produce large-sized vesicles or large-compound micelles.

    9. Highly efficient ethylene/norbornene copolymerization by o-Di(phenyl)phosphanylphenolate-based half-titanocene complexes (pages 1585–1594)

      Xiao-Yan Tang, Yong-Xia Wang, Bai-Xiang Li, Jing-Yu Liu and Yue-Sheng Li

      Version of Record online: 8 JAN 2013 | DOI: 10.1002/pola.26528

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      A series of o-di(phenyl)phosphanylphenolate-based half-titanocene complexes CpTiCl2[O-2-R1-4-R2-6-(Ph2P)C6H2] have been synthesized. Surprisingly, notable improvements in the catalytic activity were observed if introducing norbornene (NBE) into the system, and catalytic activity was more than 100 times larger than that of ethylene homopolymerization in the case of Ph3CB(C6F5)4/iBu3Al as cocatalyst. By carrying out DFT calculations, the active species is predicted and the role of NBE is identified.

    10. ESI, APCI, and MALDI tandem mass spectrometry of poly(methyl acrylate)s: A comparison study for the structural characterization of polymers synthesized via CRP techniques and the software application to analyze MS/MS data (pages 1595–1605)

      Esra Altuntaş, Andreas Krieg, Anja Baumgaertel, Anna C. Crecelius and Ulrich S. Schubert

      Version of Record online: 28 JAN 2013 | DOI: 10.1002/pola.26529

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      A comparison study of poly(methyl acrylate)s (PMA) using different (tandem) mass spectrometry techniques (ESI, APCI, MALDI MS, and MS/MS) is reported to provide insights into the macromolecular structure. Collision-induced dissociation (CID) experiments are performed to examine the fragmentation pathways of PMAs synthesized via various controlled radical polymerization (CRP) techniques. Fragmentation products are identified with the help of a dedicated tandem MS data interpretation software.

    11. Spotlight Article

      Unexpected efficiency of cyclic amidine catalysts in depolymerizing poly(ethylene terephthalate) (pages 1606–1611)

      Kazuki Fukushima, Daniel J. Coady, Gavin O. Jones, Hamid A. Almegren, Abdullah M. Alabdulrahman, Fares D. Alsewailem, Hans W. Horn, Julia E. Rice and James L. Hedrick

      Version of Record online: 9 JAN 2013 | DOI: 10.1002/pola.26530

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      This article describes the studies on the catalytic activity of several nitrogen-based organic catalysts for the depolymerization of poly(ethylene terephthalate) (PET), in which a few cyclic amidines work more effectively than a potent, bifunctional guanidine-based catalyst 1,5,7-triazabicyclo-[4,4,0]-dec-5-ene (TBD) in the presence of short-chain diols that play a role in activation of carbonyl groups through hydrogen bonding. Further studies show that the catalytic efficiency at the above specific conditions depends only on the extent of activation of a hydroxyl group rather than simply the pKa of the bases. For glycolysis with excess short-chain alkanediols, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is the best catalyst. In contrast, TBD shows outstanding catalytic activity in depolymerizations of PET with mono-alcohols and longer-chain diols.

    12. Novel pH-responsive mixed-charge copolymer brushes based on carboxylic acid and quaternary amine monomers (pages 1612–1619)

      Serkan Demirci, Selin Kinali-Demirci and Tuncer Caykara

      Version of Record online: 7 JAN 2013 | DOI: 10.1002/pola.26532

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      In this study, highly pH-responsive mixed-charged copolymer brushes are reported containing negatively charged carboxylic acid monomers (4-vinylbenzoic acid) and positively charged quaternary amine monomers ((ar-vinylbenzyl)trimethylammonium chloride) via reversible addition–fragmentation chain transfer-mediated polymerization. The brushes have negative charge under neutral and basic conditions, and are positively charged under acidic conditions owing to the protonation of the carboxylic acid groups.

    13. Spotlight Article

      pH-responsive destabilization and facile bioconjugation of new hydroxyl-terminated block copolymer micelles (pages 1620–1629)

      Behnoush Khorsand and Jung Kwon Oh

      Version of Record online: 9 JAN 2013 | DOI: 10.1002/pola.26533

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      New hydroxyl-terminated amphiphilic block copolymer micellar aggregates having pendant t-butyl groups for pH-responsiveness and terminal OH groups for bioconjugation synthesized by a consecutive atom transfer radical polymerization in the presence of an OH-terminated bromine initiator.

    14. Effect of a cocatalyst modifier in the synthesis of ultrahigh molecular weight polyethylene having reduced number of entanglements (pages 1630–1635)

      Dario Romano, Efren Alberto Andablo-Reyes, Sara Ronca and Sanjay Rastogi

      Version of Record online: 9 JAN 2013 | DOI: 10.1002/pola.26534

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      The use of a phenol-modified methylaluminoxane (MAO) cocatalyst for the synthesis of ultrahigh molecular weight polyethylene with a reduced number of entanglements is presented. The research aims, with the help of rheological analyses, to study the effects that a cocatalyst modifier has on the catalytic system performance and on the polymer produced. The results suggest that on using the phenol-modified MAO as cocatalyst, a higher number of active sites are obtained.

    15. One-step synthesis of a thienylenepyridazinylenethienylene-based coil-rod-coil copolymer with enhanced emission and improved fluorescence stability (pages 1636–1644)

      Wei Wu, Haibo Xu, Dezhi Shen, Tian Qiu and Li-Juan Fan

      Version of Record online: 9 JAN 2013 | DOI: 10.1002/pola.26535

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      A coil-rod-coil copolymer (PEG-OEPETPT-PEG) has been synthesized in one-step via Sonogashira coupling polymerization using two bifunctional small molecular mononers to form the conjugated block and one monofunctional macromolecular monomer as the coil block. The introduction of the coil onto the conjugated block retards the aggregation induced by water and therefore enhances the emission and improves the fluorescence stability of PEG-OEPETPT-PEG compared to the conjugated polymer counterpart without the coils.

    16. One-pot synthesis of precise polyisoxazoles by click polymerization: Copper (I)-catalyzed 1,3-dipolar cycloaddition of nitrile oxides with alkynes (pages 1645–1650)

      Yan Li and Bin Cheng

      Version of Record online: 12 JAN 2013 | DOI: 10.1002/pola.26537

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      In one pot, two-click reactions take place sequentially by adding the reactants step by step. The first click reaction is to produce the monomer for the second click polymerization. The click polymerization differs from the general click polymerization with the reaction of diazide and dialkyne. Nitrile oxides, produced in situ by the first click reaction, are used instead of azides, avoiding the poisonousness and explosiveness. The 3,5-disubstitute polyisoxazoles are produced by the copper(I) catalyzed 1,3-dipolar cycloaddition of nitrile oxides and alkynes with Mw/Mn < 1.2.

    17. Anionic ring-opening polymerization of a five-membered cyclic carbonate having a glucopyranoside structure (pages 1651–1655)

      Motohisa Azechi, Kozo Matsumoto and Takeshi Endo

      Version of Record online: 9 JAN 2013 | DOI: 10.1002/pola.26538

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      The effect of polymerization conditions on anionic ring-opening polymerization behaviors of the five-membered cyclic carbonate, MBCG, is investigated. The corresponding polymers are obtained in high yield by using stronger nucleophilic initiators such as n-butyllithium, lithium tert-butoxide, sodium tert-butoxide, potassium tert-butoxide, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

    18. A cyclic selenium-based reversible addition-fragmentation chain transfer agent mediated polymerization of vinyl acetate (pages 1656–1663)

      Yiyu Zhan, Zhengbiao Zhang, Xiangqiang Pan, Jian Zhu, Nianchen Zhou and Xiulin Zhu

      Version of Record online: 17 JAN 2013 | DOI: 10.1002/pola.26539

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      A cyclic selenium-based RAFT agent, RAFT-Se, was utilized in the RAFT polymerizations of VAc. RAFT-Se showed better control over molecular weights than its analog, RAFT-S. One or more RAFT-Se was incorporated into the resultant poly(VAc) main chain due to the cyclic structure. Considering the biofunction of PVAc-related polymer and the Se-containing material, this work undoubtedly presents a good junction of both.

    19. Synthesis of well-defined comb-like graft (co)polymers by nucleophilic substitution reaction between living polymers and polyhalohydrocarbon (pages 1664–1671)

      Yichao Lin, Jun Zheng, Feng Liu and Tao Tang

      Version of Record online: 12 JAN 2013 | DOI: 10.1002/pola.26540

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      A modular synthesis approach with living anionic polymerization is presented for the preparation of well-defined graft (co)polymers. Hydrozirconation of 1,2-polybutadiene and halogenolysis is achieved for controlled synthesis of the reactive backbone, which was coupled with living polymers for well-defined graft polymers. Both the backbone and the side chain are nicely designed by living anionic polymerization, for series graft polymers with tunable size, chemical composition, and grafting density.

    20. Synthesis and electro-optical properties of polyfluorene modified with randomly distributed electron-donor and rotaxane electron-acceptor structural units in the main chain (pages 1672–1683)

      Aurica Farcas, Silvia Janietz, Valeria Harabagiu, Philippe Guegan and Pierre-Henri Aubert

      Version of Record online: 24 JAN 2013 | DOI: 10.1002/pola.26546

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      Host-guest complexation of 9-dicyanomethylenefluorene (an electron-accepting molecule) into γCD cavities leads to the improvement of the fluorescence efficiency by protection from solvent quenching (decreasing nonradiative decay pathways), and hinders the aggregation tendency with beneficial effects on morphological and adhesion properties.