Quantifying How Polymer Interfacial Diffusion Differs from Bulk

ORAL

Abstract

Whereas polymer adsorption-desorption kinetics are reasonably well explored, in-plane diffusion is not. This talk will describe the molecular weight (M) and surface coverage dependence of two polymers, polystyrene (PS) and polydimethylsiloxane (PDMS) adsorbed to quartz from organic solvent. The M scaling of surface diffusion is quantified, and a surprising dependence on surface coverage is described. Time permitting, additional studies will be described in which, for the first time, polymer self-diffusion has been studied within a surface forces apparatus designed for fluorescence spectroscopy. Using FRAP (fluorescence recovery after photobleaching) to study slow diffusion and FCS (fluorescence correlation spectroscopy) to study rapid diffusion, we quantify how the self-diffusion coefficient of PDMS oligomer melts slows with diminishing surface separation, when PDMS is confined between mica surfaces.

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Authors

  • Liang Hong

    Materials Science and Engineering Department, University of Illinois at Urbana-Champaign

  • Steve Granick

    Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Departments of Physics, Chemistry, and Materials Science and Engineering, University of Illinois at Urbana-Champaign, University of Illinois at Urbana-Champaign, Dept. of Materials Science \& Engineering, of Physics, of Chemistry, and of Chemical \& Biomolecular Engineering, UIUC, Departments of Materials Science and Engineering, of Chemistry, of Physcis, University of Illinois, Department of Materials Science and Engineering, Chemistry, Physics, Chemical Engineering, University of Illinois at Urbana-Champaign, UIUC, Materials Science and Engineering Department, Department of Materials Science \& Engineering, of Chemistry, of Physics, and of Chemical \& Biomolecular Engineering, UIUC, Departments of Chemistry and of Material Science, University of Illinois