Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 50 Issue 3

1 February 2012

Volume 50, Issue 3

Pages i–iv, 155–227

  1. Cover Image

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

      Version of Record online: 22 DEC 2011 | DOI: 10.1002/polb.23026

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      Linear copolymers with a gradient change in composition along the chain backbone have a reduced driving force to phase segregate compared to block copolymers, leading to unique materials properties and phase behavior. Potential applications for such “gradient copolymers” include polymer blend compatibilizers and vibration-dampening systems. A challenge associated with studying the phase segregation of these structures is their inherently low compositional contrast, making traditional block copolymer microscopy techniques of limited use. On page 189, Michelle Mok and John Torkelson apply optical microscopy and profilometry for the first direct visualization of gradient copolymer phase segregation properties through island/hole surface features formed in thin copolymer films upon annealing.

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      Inside Cover, Volume 50, Issue 3 (pages iii–iv)

      Version of Record online: 22 DEC 2011 | DOI: 10.1002/polb.23027

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      The 2011 Nobel Prize for Chemistry was awarded for “the discovery of quasicrystals”—crystals that are ordered but not periodic, and possess “forbidden” symmetries. Such crystals in soft matter have potential photonic applications since they can be engineered with remarkable optical properties and photonic bandgaps. On page 155, Tomonari Dotera provides a quick introduction of quasicrytals, rational design, and realization of ‘soft’—including block copolymer, colloid, and liquid crystalline—quasicrystals. Approaches to finding new quasicrystals is a particular focus. The cover depicts a rendering of a potion of the (3.3.4.3.4) Archimedean tiling phase from ABC star terpolymers, closely related to the first discovery of polymeric quasicrystals.

  2. Reviews

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Communication
    5. Full Papers
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      Toward the discovery of new soft quasicrystals: From a numerical study viewpoint (pages 155–167)

      Tomonari Dotera

      Version of Record online: 18 NOV 2011 | DOI: 10.1002/polb.22395

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      The 2011 Nobel Prize for Chemistry was awarded for “the discovery of quasicrystals” — crystals that are ordered but not periodic, and possess “forbidden” symmetries. Such crystals have potential photonic applications since they can be engineered with remarkable optical properties and photonic bandgaps. In this Review, after providing a quick introduction of quasicrytals, rational design and realization of ‘soft’—including polymer, colloid, and liquid crystalline—quasicrystals is examined. Approaches to finding new quasicrystalsis a particular focus.

  3. Communication

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Communication
    5. Full Papers
    1. Molecular layer-by-layer deposition of highly crosslinked polyamide films (pages 168–173)

      Peter M. Johnson, Joonsung Yoon, Jennifer Y. Kelly, John A. Howarter and Christopher M. Stafford

      Version of Record online: 19 NOV 2011 | DOI: 10.1002/polb.23002

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      Layer-by-layer assembly provides exquisite control over the functionality of polymer films at the monomer lengthscale. A molecular layer-by-layer process is presented for the assembly of highly crosslinked polyamide from successive isolated exposure of trimesoyl chloride and m-phenylene diamine. Films grow linearly at ≈0.9 nm per cycle, with a minimal increase in surface roughness. As compared with commercial methods which use interfacial polymerization, this technique enables polyamide films with well-defined film thickness and network structure.

  4. Full Papers

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Communication
    5. Full Papers
    1. In situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics (pages 174–179)

      Christopher G. Shuttle, Neil D. Treat, Jian Fan, Alessandro Varotto, Craig J. Hawker, Fred Wudl and Michael L. Chabinyc

      Version of Record online: 31 OCT 2011 | DOI: 10.1002/polb.22388

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      Bulk heterojunction (BHJ) solar cells are attractive for their power conversion efficiencies, but the effects on efficiency of changing individual components can be complicated to assess. Here, in situ current-voltage measurements are used to determine appropriate conditions for improving the efficiency of a new fullerene derivative in BHJs with poly(3-hexylthiophene). This approach decreases the number of samples required to determine optimal processing conditions by an order of magnitude and could be used to look at annealing effects in large-area processing systems.

    2. Stable and good color purity white light-emitting devices based on random fluorene/spirofluorene copolymers doped with iridium complex (pages 180–188)

      Hong-Yu Wang, Qun Qian, Kun-Hua Lin, Bo Peng, Wei Huang, Feng Liu and Wei Wei

      Version of Record online: 31 OCT 2011 | DOI: 10.1002/polb.22391

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      Two random copolymers, PSNFP and PSNFF, which are based on a naphthalene-containing spirofluorene structure, are designed and synthesized for light-emitting applications. The monochromatic devices based on PSNFF and the white light-emitting diodes based on PSNFF doped with iridium complexes—a green emitter Ir(mppy)3 and a red emitter Ir(piq)2—are prepared. The devices show good color purity and the electroluminescence spectra also show good stability upon change of the current density.

    3. Imaging of phase segregation in gradient copolymers: Island and hole surface topography (pages 189–197)

      Michelle M. Mok and John M. Torkelson

      Version of Record online: 31 OCT 2011 | DOI: 10.1002/polb.22393

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      Gradient sequencing rather than block sequencing within linear copolymers yields phase-segregated nanostructures with sinusoidal composition profiles rather than step-like profiles. As a result, the application of traditional block copolymer microscopy techniques to gradient copolymers yields limited results, due to their low compositional contrast. Here, optical microscopy and profilometry are applied to demonstrate the first direct visualization of gradient copolymer phase segregation properties through island/hole surface features formed in thin films on annealing.

    4. Poly(3-hexylselenophene) solar cells: Correlating the optoelectronic device performance and nanomorphology imaged by low-energy scanning Transmission electron microscopy (pages 198–206)

      Michael F. G. Klein, Marina Pfaff, Erich Müller, Jens Czolk, Manuel Reinhard, Sebastian Valouch, Uli Lemmer, Alexander Colsmann and Dagmar Gerthsen

      Version of Record online: 7 NOV 2011 | DOI: 10.1002/polb.22394

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      Although poly(3-hexylthiophene-2,5-diyl) is a widely studied polymer for use in organic solar cells, its selenium equivalent poly-(3-hexylselenophene-2,5-diyl) (P3HS) is a promising alternative due to a reduced optical band gap. Device properties of P3HS:[6,6]-phenyl C61-butyric acid methyl ester polymer solar cells are studied by means of current/voltage measurements, absorption spectra, and time-dependent photoresponse. The results are correlated with a comprehensive nanoscale study of the respective bulk-heterojunctions. Low-energy high-angle annular dark-field scanning transmission electron microscopy is used to analyze the morphology of the system. Those images are quantitatively analyzed by spatial Fourier transform. The formation of P3HS whiskers upon thermal annealing results in enhanced mobility.

    5. Stiffness constants prediction of nanocomposites using a periodic 3D-FEM model (pages 207–220)

      Gabriele Cricrì, Emilia Garofalo, Francesco Naddeo and Loredana Incarnato

      Version of Record online: 19 NOV 2011 | DOI: 10.1002/polb.23001

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      Theoretical models, which enable the prediction of nanocomposite properties from their morphologies and account for polymer orientation, could greatly assist the exploitation of this new class of materials in more diversified and demanding market fields. This manuscript, incorporating the combination of experiments, numerical computations, and theory, focuses on the modeling of mechanical behavior of polyamide-based nanocomposites, produced by means pilot-scale film blowing equipment and collected at different draw ratios.

    6. Controlled release of drug via tuning electrospun polymer carrier (pages 221–227)

      Xiaofeng Song, Zhantuan Gao, Fengguang Ling and Xuesi Chen

      Version of Record online: 29 NOV 2011 | DOI: 10.1002/polb.23005

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      Electrospinning is a simple and flexible method for entrapping drugs and tailoring the release behavior from polymeric carriers for drug delivery. Here, medicated polymer fibers are obtained through electrospinning of polymer solution in which the bactericidal antibiotic drug rifampin had also been dissolved. The relationship between polymer variables (such as concentration, molecular weight, and introducing a hydrophilic block) and the release of the co-dissolved drug from the electrospun fibers is established.

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