Gravitational collapse of depletion gels

ORAL

Abstract

We study how colloidal gels collapse under the presence of a gravitational stress. We do so macroscopically, monitoring the time dependence of the creaming or sedimentation front, and microscopically, using confocal microscopy. Our system consists of fluorescently labeled spheres that are index matched to the surrounding solvent. Temperature allows fine control of the density mismatch, further enabling fine tuning of the gravitational stress. Addition of non-adsorbing polymer induces an attraction whose range and strength can also be tuned. We will present results pertaining macroscopic studies for different particle volume fractions and interaction energies and preliminary microscopic results aiming to locally describe the structure collapse.

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Authors

  • Juan Jose Lietor-Santos

    Division of Engineering and Applied Science. Harvard University

  • Alberto Fernandez-Nieves

    Harvard University, Division of Engineering and Applied Science, Harvard University, Cambridge MA 02138, USA, Division of Engineering and Applied Science. Harvard University

  • Chanjoong Kim

    DEAS, Harvard University, Cambridge, MA 02138, USA, DEAS, Harvard University, Division of Engineering and Applied Science. Harvard University

  • Peter J. Lu

    Division of Engineering and Applied Science. Harvard University

  • David Weitz

    Division of Engineering and Applied Sciences and Department of Physics, Harvard University, DEAS, Harvard University, Cambridge, MA 02138, USA, Harvard University, DEAS, Harvard University, Division of Engineering and Applied Science, Harvard University, Cambridge MA 02138, USA, Division of Engineering and Applied Science. Harvard University, Applied Physics, Harvard University