Self-similarity and energy dissipation in stepped polymer films

ORAL

Abstract

We have recently learned how to prepare polymer films whose only feature is a step in the height profile. In the melt, Laplace pressure drives a flow that levels the topography, with the excess energy of the height step being dissipated by viscosity. It has been observed that the profiles are self-similar in time for a variety of molecular weights and geometries. Given the surface tension, this simple observation allows a precise measurement of the viscosity by comparison with numerical solutions of the thin film equation. It is also possible to derive a master expression for the time dependence of the excess surface energy as a function of the material properties and film geometry. Thus, all geometries and molecular weights fall on a single temporal curve. The material parameter allowing this collapse is the capillary velocity -- the ratio of the surface tension to the viscosity.

*The authors thank NSERC of Canada, the ENS of Paris, the German DFG (grant no. BA3406/2), the Chaire Total-ESPCI, and the Saint Gobain Fellowship for financial support.

–

Authors

  • Joshua McGraw

    • Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada, L8S 4M1
    • Department of Physics \& Astronomy and the BIMR, McMaster University, Hamilton, ON, Canada

  • Thomas Salez

    • Laboratoire de Physico-Chimie Theorique, UMR CNRS Gulliver 7083, ESPCI, Paris, France

  • Oliver Baeumchen

    • Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada, L8S 4M1
    • Department of Physics \& Astronomy and the BIMR, McMaster University, Hamilton, ON, Canada

  • Elie Rapha\"el

    • Laboratoire de Physico-Chimie Theorique, UMR CNRS Gulliver 7083, ESPCI, Paris, France
    • ESPCI

  • Kari Dalnoki-Veress

    • Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada, L8S 4M1
    • Department of Physics \& Astronomy and the Brockhouse Institute for Materials Research, McMaster University, Hamilton, Canada
    • Department of Physics \& Astronomy and the BIMR, McMaster University, Hamilton, ON, Canada
    • Department of Physics and Astronomy, McMaster University, Hamilton, ON, Canada
    • Physics and Astronomy, McMaster University