Surface Dynamics of Polymer Brushes in the Melt State: An XPCS Study

ORAL

Abstract

The suppression of long-wavelength modes of surface fluctuations on a molten polymer brush has been demonstrated using direct measurements of dynamics for the first time. The surface dynamics of densely grafted polystyrene brushes of reasonably monodisperse chains were investigated by X-ray photon correlation spectroscopy. Within the range of time and length scale investigated, 0.2 s to 1000 s, and 200 nm to 5 um, there were no detectable dynamics on the brush surfaces, even 130 C above the polymer bulk glass transition temperature. A comparably thick film of untethered chains has a q-dependent surface relaxation time of the order of 30 s, indicating that the tethering of the chains alters the surface relaxation rate by at least 3 orders of magnitude. Such a suppression of long wavelength fluctuations on the surface of a molten brush was predicted by Frederickson and co-workers.

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Authors

  • Mark Foster

    • University of Akron, Dept. of Polymer Science
    • Maurice Morton Institute of Polymer Science, The University of Akron, Akron, OH 44325
    • The University of Akron, Akron, OH 44325-3909
    • Dept of Polymer Science, The University of Akron

  • Bulent Akgun

    • Maurice Morton Institute of Polymer Science, The University of Akron, Akron, OH 44325

  • Gokce Ugur

    • Maurice Morton Institute of Polymer Science, The University of Akron, Akron, OH 44325

  • William J. Brittain

    • Univ. of Akron, Akron, OH 44325-3909

  • Suresh Narayanan

    • Advanced Photon Source, Argonne, IL 60439
    • X-ray Science Division, Argonne National Lab, Argonne, IL 60439
    • Argonne National Laboratory
    • Advanced Photon Source, Argonne National Lab
    • X-ray Science Division, Argonne National Laboratory, Argonne, IL 60439
    • Argonne National Lab

  • Heeju Lee

    • Dept. of Physics, Sogang University, Korea

  • Sanghoon Song

  • Hyunjung Kim

    • Dept. of Physics, Sogang Univ., Seoul 121-742, Korea
    • Physics \& Interdisciplinary program of Integrated Biotechnology, Sogang U., Korea
    • Department of Physics \& Interdisciplinary Program of Integrated Biotechnology, Sogang University, Korea
    • Department of Physics, Sogang University, Seoul 121-742, Korea

  • Zhang Jiang

    • University of California, San Diego, CA 92093
    • Department of Physics, University of California at San Diego
    • Sogang University

  • Sunil Sinha

    • University of California, San Diego, CA 92093
    • Department of Physics, University of California, San Diego, La Jolla, CA-92093, USA.
    • Dept. of Physics, Univ. of California San Diego, La Jolla, CA 92093
    • Department of Physics, University of California at San Diego
    • University of California, San Diego
    • Department of Physics, University of California San Diego, La Jolla, CA 92093
    • University of California, San Diego and Los Alamos National Laboratory