Particle dynamics in colloidal glasses with short-range attraction

ORAL

Abstract

We study colloidal particle dynamics of a model glass system using confocal microscopy as the sample evolves from a repulsive glass towards an attractive glass. Short-range depletion forces induce the transition from a repulsive glass to the attractive glass. We identify particles which exhibit substantial motional events and characterize the transition using the properties of these motional events. It appears that number of particles that exhibit motional events doesn't change as the system is brought from a repulsive glass towards the attractive glass. Also, we investigate vibrational properties of these dense colloidal suspensions. Our preliminary results show that the boson peak for an attractive glass is lower than that for a repulsive system and it is shifted towards higher frequencies. To our knowledge, this is the first experimental investigation of the evolution of vibrational modes in colloidal glasses when particle interaction potential changes from repulsive to attractive.

*P.H., M.I., D.F., J.M.D, L.M. acknowledge support of HHMI and Sigma Xi. L.M. acknowledges support of McNulty Scholars Program. A.G.Y. acknowledges financial support of the NSF Grants No. DMR-0804881, PENN MRSEC No. DMR11-20901, and NASA Grant NNX08AO0G

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Authors

  • Piotr Habdas

    • Department of Physics, Saint Joseph's University
    • Saint Joseph's University

  • Ke Chen

    • Department of Physics \& Astronomy, University of Pennsylvania

  • Martin Iwanicki

    • Department of Physics, Saint Joseph's University

  • Daniel Flynn

    • Department of Physics, Saint Joseph's University

  • John Michael Devany

    • Department of Physics, Saint Joseph's University

  • Lisa Mariani

    • Department of Physics, Saint Joseph's University
    • Saint Joseph's University

  • Arjun Yodh

    • Department of Physics and Astronomy, University of Pennsylvania
    • Department of Physics \& Astronomy, University of Pennsylvania
    • University of Pennsylvania
    • Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104, USA