August 11, 1990 - August 11, 2023

  • Date:16SundayFebruary 2020

    Shaping liquid droplets and elastic membranes

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    Edna and K.B. Weissman Building of Physical Sciences
    Drory Auditorium
    Zvonimir Dogic
    Clore Center for Biological Physics
    AbstractShow full text abstract about We describe two self-assembly pathways observed in micron-th...»
    We describe two self-assembly pathways observed in micron-thick colloidal membranes that spontaneously assemble in mixtures of monodisperse colloidal rods and non-adsorbing polymer. In a first example, we study mechanisms by which membrane-embedded 2D liquid droplets acquire unusual non-spherical shapes, suggesting that the interfacial edge domain has spontaneous non-zero edge curvature. These experimental observations can be explained by a simple geometric argument which predicts that the edge curvature towards shorter rod domains softens the resistance of the edge to twist. In a second example, we study the 3D structure of membranes composed of miscible rod-like molecules of differing lengths. Above a critical concentration of shorter rods flat 2D membranes become unstable and assume a bewildering variety of different shapes and topologies. Simple arguments suggest that doping colloidal membranes with miscible shorter rods tunes the membrane’s Gaussian modulus, which in turn destabilizes flat 2D membranes.