Plug flow in a viscous freely-suspended film

ORAL

Abstract

The flow of viscous polymer liquids supported by a solid substrate has been well characterized by a variety of experimental techniques. Previous studies found that the velocity profile within a flowing liquid film depends strongly on the friction at the liquid-substrate interface. For the case of low interfacial friction, liquid molecules can slide along the solid substrate. This is the ``slip'' boundary condition. Here we probe flow in a system with no interfacial friction: a viscous polymer film suspended at its edges. Using AFM, we measure the capillary-driven relaxation of freestanding polymer films with an initially stepped film thickness profile. The time evolution of the profile is consistent with plug flow. A freely-suspended viscous polymer film provides a physical realization of an idealized infinite slip boundary condition. Interestingly, in such a context, the profile evolution satisfies a diffusion-like equation, thus allowing for the use of a broad mathematical and physical toolbox by analogy.

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Authors

  • Kari Dalnoki-Veress

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

  • Mark Ilton

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

  • Miles Couchman

    Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada, L8S 4M1

  • Thomas Salez

    Laboratoire de Physico-Chimie Th\'{e}orique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France, Gulliver UMR 7083, ESPCI

  • Michael Benzaquen

    UMR CNRS 7083 Gulliver, ESPCI ParisTech, 10 Rue Vauquelin 75005 Paris, France, Laboratoire de Physico-Chimie Th\'{e}orique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France, Gulliver UMR 7083, ESPCI

  • Paul Fowler

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

  • Elie Raphael

    ESPCI, Laboratoire de Physico-Chimie Th\'{e}orique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris, France, Gulliver UMR 7083, ESPCI