Capillary interactions between anisotropic colloidal particles

ORAL

Abstract

We report on the behavior of micron-sized prolate ellipsoids trapped at an oil-water interface. The particles experience strong, anisotropic, and long-ranged attractive capillary interactions which greatly exceed the thermal energy $k_{B}T$. Depending on surface chemistry, the particles aggregate into open structures or chains. Using video microscopy, we extract the pair interaction potential between ellipsoids and show it exhibits a power law behavior over the length scales probed. Our observations can be explained using recent calculations, if we describe the interfacial ellipsoids as capillary quadrupoles.

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Authors

  • Jean-Christophe Loudet

    Centre de Recherche Paul Pascal, CNRS, Avenue A. Schweitzer 33600 Pessac, FRANCE

  • A.M. Alsayed

  • J. Zhang

  • A.G. Yodh

    Dept of Physics and Astronomy, University of Pennsylvania, Department of Physics and Astronomy, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104-6396, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA, Dept. of Physics \& Astronomy, University of Pennsylvania