Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 51 Issue 11

June 2013

Volume 51, Issue 11

Pages i–ii, 855–925

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Perspectives
    4. Full Papers
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      Cover Image, Volume 51, Issue 11 (pages i–ii)

      Version of Record online: 19 APR 2013 | DOI: 10.1002/polb.23299

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      Uniform thin films of polymer blends can be produced through spin-coating, which is used as a research tool and on an industrial scale for the production of light-emitting diodes, and more recently organic photovoltaic devices. Toolan et al. present, on page 875, the direct observation of morphological developments during the spin-coating of blends of polystyrene and poly(methyl methacrylate), using their recently developed technique of high-speed stroboscopic interference microscopy. They show that the mechanism by which the final morphology is formed is through domain coarsening when rich in solvent, before vitrification occurs and fixes the phase-separated structure. This study also opens the possibility of introducing feedback during spin-coating, to affirm greater control over morphological development, which could lead to the production of more efficient organic electronic devices.

  2. Perspectives

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      Liquid crystal functionalization of electrospun polymer fibers (pages 855–867)

      Dae Kyom Kim, Minsik Hwang and Jan P. F. Lagerwall

      Version of Record online: 29 MAR 2013 | DOI: 10.1002/polb.23285

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      Electrospinning provides a convenient means of functionalizing polymer fibers with liquid crystals, giving them strong response function and new application potential. As shown in this Perspective, this novel class of composite provides an excellent platform for innovative cross fertilization between various current fields of polymer and liquid crystal science. The current state of the art of the field and possible future directions are discussed, particularly for applied research.

  3. Full Papers

    1. Top of page
    2. Cover Image
    3. Perspectives
    4. Full Papers
    1. Improved phase separation in polymer solar cells by solvent blending (pages 868–874)

      Christian Kästner, Burhan Muhsin, Andreas Wild, Daniel A. M. Egbe, Silke Rathgeber and Harald Hoppe

      Version of Record online: 2 APR 2013 | DOI: 10.1002/polb.23286

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      Thin-film blend morphology and solar cell performance is systematically studied as a function of solvent composition (chlorobenzene to chloroform ratio) and polymer to fullerene ratio, showing that the blend morphology of the investigated system becomes independent of the supporting solvent for high-fullerene concentrations. Deposition from solvent blends rather than from pure chlorobenzene facilitates beneficial phase separation between polymer and fullerene, leading to improved charge transport properties (short-circuit currents) at lower fullerene concentrations.

    2. Direct observation of morphological development during the spin-coating of polystyrene–poly(methyl methacrylate) polymer blends (pages 875–881)

      Daniel T. W. Toolan, Ehtsham ul Haq, Alan Dunbar, Stephen Ebbens, Nigel Clarke, Paul D. Topham and Jonathan R. Howse

      Version of Record online: 27 MAR 2013 | DOI: 10.1002/polb.23288

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      The real-space direct observation of the phase separation of high molecular weight polystyrene and poly(methyl methacrylate) is accomplished using the technique of high-speed stroboscopic interference microscopy. Through varying the rotational rate, the formation of a range of phase-separated bicontinuous morphologies of differing length-scales can be observed. The mechanism by which the morphology is formed is shown to be through domain coarsening when rich in solvent, before vitrificaiton occurs and fixes the phase-separated structure.

    3. Effect of biaxial orientation on dielectric and breakdown properties of poly(ethylene terephthalate)/poly(vinylidene fluoride-co-tetrafluoroethylene) multilayer films (pages 882–896)

      Joel M. Carr, Matthew Mackey, Lionel Flandin, Donald Schuele, Lei Zhu and Eric Baer

      Version of Record online: 8 MAR 2013 | DOI: 10.1002/polb.23277

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      Multilayer films containing alternating layers of poly(ethylene terephthalate) and poly(vinylidene fluoride-co-tetrafluoroethylene) were fabricated using forced assembly multilayer coextrusion. These materials exhibit enhanced dielectric, breakdown, and energy density properties as a result of multilayered structure. Additionally, the synergistic combination of multilayering and biaxial orientation was used to further improve these properties. Biaxial stretching effectively manipulates the confined structures of both layers, which has a direct influence on the dielectric and breakdown properties.

    4. Plastic deformation behavior of polypropylene sheet with transversal orientation (pages 897–906)

      Panitha Phulkerd, Hiroki Hagihara, Shogo Nobukawa, Yohei Uchiyama and Masayuki Yamaguchi

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/polb.23278

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      A polypropylene (PP) sheet in which molecules orient perpendicular to the flow direction is successfully prepared by taking advantage of a peculiar crystal growth of PP from needle-shaped nucleating agents. The deformation mechanism during stretching, including the void formation, is studied for this sheet. It is found that stretching in the machine direction generates a microporous film. In contrast, a shear yielding deformation is dominant without microvoid formation when stretched in the transverse direction.

    5. Relaxation dynamics of stretched polymer chains traced by shear induced Shish-Kebab structure (pages 907–914)

      Xi Jiang, Qi Liao, Jianjun Zhou, Zhaohui Wang, Chiming Chan and Lin Li

      Version of Record online: 11 MAR 2013 | DOI: 10.1002/polb.23281

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      Shear- or flow-induced orientation of a polymer melt, in particular shish-kebab formation, has significant effects on the polymer properties. In this work, the time dependence of length of the isolated shish-kebab structure and the stress dependence of the kebab density along the direction of shish was studied. The shear-oriented polymer melts show the relaxation dynamics of worm-like chains, where the length deficit of the isolated shish-kebab structure is scaled with the relaxation time as a power of 1/3.

    6. Mechanical properties of perfluoro sulfonated acids: The role of temperature and solute activity (pages 915–925)

      Qiao Zhao and Jay Benziger

      Version of Record online: 11 MAR 2013 | DOI: 10.1002/polb.23284

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      Perfluorosulfonic acids (PFSAs) are employed as electrolytes in fuel cells. The rigidity of PFSAs changes significantly between 50 and 90 °C. Below this temperature water absorption makes the PFSA more flexible, above this temperature water absorption makes the PFSA more rigid. Increasing the temperature where the rigidity changes can improve the expected lifetime of membranes in fuel cells.

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