Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 50 Issue 5

1 March 2012

Volume 50, Issue 5

Pages i–ii, 305–377

  1. Cover Image

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

      Version of Record online: 20 JAN 2012 | DOI: 10.1002/polb.23042

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      The search for an inexpensive, flexible, and light-weight electrode for batteries and supercapacitors has led to wide-ranging investigations on polypyrrole because of its easy electrochemical processability, high charge storage ability, biocompatibility, and good thermal and environmental stability. The interaction between the anion and the polymer chain holds the key to the genesis of its structural, optical, and electrical properties. The inorganic anions show 3D-type growth leading to fractal morphology whereas organic anions form a compact stack with the polymer backbone exhibiting a laminar structure. The investigation by Rajiv K. Singh, Amit Kumar, Khushboo Agarwal, Mahesh Kumar, H. K. Singh, Pankaj Srivastava, and Ramadhar Singh on page 347 reveals that the anions used for polymerization have considerable impact on the growth mechanism.

  2. Reviews

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    3. Reviews
    4. Communications
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      Advanced materials based on polymer cocrystalline forms (pages 305–322)

      Gaetano Guerra, Christophe Daniel, Paola Rizzo and Oreste Tarallo

      Version of Record online: 5 JAN 2012 | DOI: 10.1002/polb.23035

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      Polymeric cocrystalline forms present low-molecular-mass guest molecules in cavities, channels or layers, as defined by the crystalline organization of a polymer host. Cocrystalline films with active guest molecules, as reviewed here, have found optical, magnetic and electric applications. In a few cases, the polymer host structure remains essentially unaltered after guest removal, thus leading to the formation of nanoporous crystalline forms, which are extremely efficient for molecular separations and sensors.

  3. Communications

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    3. Reviews
    4. Communications
    5. Full Papers
    1. Core extractable nano-objects: Manipulating triblock copolymer micelles (pages 323–327)

      Lei Gao, Ke Zhang, Bo Peng, Yi Shi and Yongming Chen

      Version of Record online: 6 DEC 2011 | DOI: 10.1002/polb.23009

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      Stimuli-responsive block copolymers can form various morphologies depending on, for example, pH, temperature, or proper choice of solvent. By changing the dispersing solvent, the structure of nano-objects from triblock copolymer micelles can be manipulated from solid to hollow spheres. The transition is attributed to the migration of core-block chains across the crosslinked shells of the micelles and makes them attractive for applications such as encapsulation for drug and gene delivery.

  4. Full Papers

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Communications
    5. Full Papers
    1. Characterization of the mesostructure of HDPE under “in situ” uniaxial tensile test by incoherent polarized steady-light transport (pages 328–337)

      A. Blaise, C. Baravian, J. Dillet, L.J. Michot and S. André

      Version of Record online: 13 DEC 2011 | DOI: 10.1002/polb.23020

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      When high density polyethylene is stretched, it noticeably whitens in the deformed region, indicating an increase in turbidity. To quantify the whitening of semicrystalline polymers during in situ drawing, a new technique based on incoherent polarized light scattering is presented, elucidating what happens in the microstructure. It can be applied to solid or liquid systems when changes in turbidity occur by some internal processes at the microscale. This low-cost technique provides the same type of results as those obtained using synchrotron X-ray microtomography.

    2. Correlating backbone-to-backbone distance to ionic conductivity in amorphous polymerized ionic liquids (pages 338–346)

      David Salas-de la Cruz, Matthew D. Green, Yuesheng Ye, Yossef A. Elabd, Timothy E. Long and Karen I. Winey

      Version of Record online: 15 DEC 2011 | DOI: 10.1002/polb.23019

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      By varying the chemical structure of ionic liquid monomers, the morphology and ionic conductivity of polymerized ionic liquids can be controlled. The morphology and ionic conductivity of poly(1-n-alkyl-3-vinylimidazolium)-based poly(nVIM-X) homopolymers polymerized from ionic liquids are investigated as a function of the alkyl chain length and counterion type. X-ray scattering of the homopolymers provides morphological information to determine ionic conductivity. While increasing the pendant length can decrease Tg to increase conductivity, this also increases the intermolecular separation, which acts to decrease ionic conductivity.

    3. DC electrical conduction and morphological behavior of counter anion-governed genesis of electrochemically synthesized polypyrrole films (pages 347–360)

      Rajiv K. Singh, Amit Kumar, Khushboo Agarwal, Mahesh Kumar, H. K. Singh, Pankaj Srivastava and Ramadhar Singh

      Version of Record online: 29 NOV 2011 | DOI: 10.1002/polb.23006

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      Because of its high charge storage ability, polypyrrole (PPY) is a good candidate for applications in batteries or supercapacitors. The growth mechanism of PPY is influenced by the nature of dopant anion used for polymerization. Doping with an inorganic anion leads to fractal growth, whereas the aromatic interaction between organic dopant anion and π-conjugation of the polymer backbone leads to laminar growth. The interaction between dopant anion and polymer chain is, therefore, a key factor influencing structural, optical, and electrical properties.

    4. On the formation mechanism for electrically generated exciplexes in a carbazole–pyridine copolymer (pages 361–369)

      Anna Hayer, Tanguy Van Regemorter, Bianca Höfer, Chris S. K. Mak, David Beljonne and Anna Köhler

      Version of Record online: 13 DEC 2011 | DOI: 10.1002/polb.23011

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      Understanding the formation of exiplexes is essential to improving device efficiency of organic light-emitting diodes (OLEDs). Using a copolymer model compound, the formation of exciplexes in operating OLEDs is shown to proceed by a two-step mechanism associated with nitrogen containing moieties. A hole localizes on the carbazole moiety and forms a charged inter-chain precursor complex, resulting in exciplex formation when an electron gets trapped on the precursor complex. Quantum chemical calculations demonstrate the role of a specific nitrogen-–nitrogen interaction in this process.

    5. Impact of chain architecture (branching) on the thermal and mechanical behavior of polystyrene thin films (pages 370–377)

      Jessica M. Torres, Christopher M. Stafford, David Uhrig and Bryan D. Vogt

      Version of Record online: 6 DEC 2011 | DOI: 10.1002/polb.23014

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      Branching architecture of polymers is known to significantly affect the thermal and mechanical behavior of thin films. Here, the modulus and glass transition temperature (Tg) of four different architectures (linear, comb, centipede, and four-armed star) of polystyrene thin films are examined as a function of thickness. The elastic modulus for the comb PS is independent of film thickness, whereas the other architectures exhibit a significant decrease in modulus for thin films. These differences are attributed to differences in chain conformation with branching.

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