Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 50 Issue 8

15 April 2012

Volume 50, Issue 8

Pages i–ii, 523–589

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Full Papers
    5. Erratum
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      Cover Image, Volume 50, Issue 8 (pages i–ii)

      Version of Record online: 2 MAR 2012 | DOI: 10.1002/polb.23062

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      Spherulitic morphology in block copolymers composed of miscible crystalline components show unique structures that are different from those in blends, as presented by Takayuki Ikehara, Hideo Kurihara, and Toshiyuki Kataoka on page 563. This is ascribed to the chain connectivity; the blocks of one component are confined between crystalline lamellae of the other component. The crystallization of the confined polymer is suppressed even if it is the component with the higher melting point. When the confining lamellae are melted in a heating process, the released component immediately nucleates and creates many crystals. Then, they continue growing with dendritic morphology.

  2. Reviews

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    3. Reviews
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      Electrostrictive polymers for mechanical energy harvesting (pages 523–535)

      Mickaël Lallart, Pierre-Jean Cottinet, Daniel Guyomar and Laurent Lebrun

      Version of Record online: 6 FEB 2012 | DOI: 10.1002/polb.23045

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      Research into the use of electrostrictive polymers—materials that deform under the influence of an electric field—for energy generation has been growing in intensity over the last few years. Light weight, low cost, and flexibility in both shape and mechanical deformation make them ideal for applications. This review examines the recent advances in the field, the principles, mechanisms, and advantages, as well as focuses on the future challenges in the main research.

  3. Full Papers

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Full Papers
    5. Erratum
    1. Manufacture and demonstration of organic photovoltaic-powered electrochromic displays using roll coating methods and printable electrolytes (pages 536–545)

      Jacob Jensen, Henrik F. Dam, John R. Reynolds, Aubrey L. Dyer and Frederik C. Krebs

      Version of Record online: 17 JAN 2012 | DOI: 10.1002/polb.23038

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      Organic and polymeric electrochromics are attractive for their ease of processing printable materials and low power consumption. The efficient and fast manufacture of large area flexible electrochromic devices on polyester substrates through roll coating is demonstrated using both spray and slot-die coating methods. Product integration is demonstrated in a stand-alone electrochromic device powered by roll-to-roll coated and printed polymer solar cell modules. Key to the structure is a printable electrolyte system that allows for good adhesion between the individual layers of the multilayer device.

    2. Measurement of size-dependent glass transition temperature in electrospun polymer fibers using AFM nanomechanical testing (pages 546–551)

      Wei Wang and Asa H. Barber

      Version of Record online: 29 DEC 2011 | DOI: 10.1002/polb.23030

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      The thermal behavior of electrospun fibers with differing diameters is governed by polymer chain entanglements formed in the electrospinning process. The glass transition temperature (Tg) of individual electrospun poly-vinyl alcohol fibers was measured here using atomic force microscopy (AFM)-based nanomechanical bending and indentation testing during fiber heating. A drop in the bulk polymer Tg was recorded when the fiber diameter decreased below 250 nm, which indicated polymer chain confinement within the electrospun fiber.

    3. Anion exchange membranes derived from nafion precursor for the alkaline fuel cell (pages 552–562)

      Holly L. S. Salerno, Frederick L. Beyer and Yossef A. Elabd

      Version of Record online: 29 DEC 2011 | DOI: 10.1002/polb.23033

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      Nafion-based anion exchange membranes (AEMs) are synthesized via amination of the Nafion precursor membrane with 1,4-dimethylpiperazine and subsequent ion exchange. These AEMs possess high thermal stability and different thermal transition temperatures compared to Nafion, while small-angle X-ray scattering reveals a similar ionic morphology. The high chemical and thermal stability and good hydroxide conductivities of these Nafion-based AEMs provide a promising alternative for alkaline fuel cells.

    4. Spherulitic growth in block copolymers and blends of miscible crystalline polymers (pages 563–571)

      Takayuki Ikehara, Hideo Kurihara and Toshiyuki Kataoka

      Version of Record online: 5 JAN 2012 | DOI: 10.1002/polb.23036

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      Crystallization and the formation of interpenetrating spherulites can create characteristic morphology in miscible copolymers. Spherulitic growth and morphology in block copolymers with two miscible crystalline components are reported, and the results are compared with those of the blends. The connectivity between the block chains in the copolymers influences the lamellar stack structures and crystallization dynamics. Copolymers form interpenetrating spherulites, where spherulites of one component grow in those of the other component, as in the blends.

    5. Synthesis of PVDF/BiFeO3 nanocomposite and observation of enhanced electrical conductivity and low-loss dielectric permittivity at percolation threshold (pages 572–579)

      Debabrata Bhadra, Md. G. Masud, S. Sarkar, J. Sannigrahi, S. K. De and B. K. Chaudhuri

      Version of Record online: 31 JAN 2012 | DOI: 10.1002/polb.23041

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      Multiferroic polymer composite films consisting of an insulating polymer host (PVDF) and multiferroic BiFeO3 nanoparticles are promising device grade materials for smart capacitor applications requiring high dielectric permittivity and low loss. A flexible, two-phase polymer nanocomposite thick film was designed using simple hot molding, and the dielectric and ferroelectric properties of these composite were investigated. The composite possessed extraordinarily high dielectric permittivity (∼103) and low dielectric loss (∼0.18) at the percolation threshold (fc = 0.12) and good ferroelectric character.

    6. The friction coefficient on polycarbonate as a function of the contact pressure and nanoscale roughness (pages 580–588)

      A. Rubin, C. Gauthier and R. Schirrer

      Version of Record online: 1 FEB 2012 | DOI: 10.1002/polb.23046

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      The surface mechanical properties of many polymeric materials are of major interest to ensure their longevity for applications such as overcoats that enhance frictional properties in bearings and gears, biomedical implants, and so on. In this article, the frictional properties of polycarbonate surfaces are examined using sliding experiments with spherical indenters. The mechanisms responsible for the friction observed, along with the effects of experimental parameters such as contact pressure, are discussed.

  4. Erratum

    1. Top of page
    2. Cover Image
    3. Reviews
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    5. Erratum
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      Erratum: Graphitic nanofillers in PMMA nanocomposites—an investigation of particle size and dispersion and their influence on nanocomposite properties (page 589)

      T. Ramanathan, S. Stankovich, D. A. Dikin, H. Liu, H. Shen, S. T. Nguyen, K. Putz and L. C. Brinson

      Version of Record online: 31 JAN 2012 | DOI: 10.1002/polb.23037

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