Self-assembly of Janus ellipsoids

Condensed Matter lunchtime seminar

Self-assembly of Janus ellipsoids

  • Event time: 1:00pm
  • Event date: 20th June 2014
  • Speaker: Michael J. Solomon (University of Michigan Ann Arbor)
  • Location: Room 2511,

Event details

Assemblies of colloidal particles are common both in nature and in advanced materials. Such assemblies are also useful for forming reconfigurable soft matter. Anisotropic colloids, now widely available due to advances in synthesis, are rapidly expanding the types of structures that can be assembled relative to the classical case of isotropically interacting colloids. Here we investigate how two anisotropy dimensions – ellipsoidal shape and Janus interactions – combine to yield unusual propensities for self-assembly. The particles, Janus ellipsoids, are produced by stretching latex spheres into ellipsoids, followed by evaporative deposition of a layer of gold onto one-half of the particle. In aqueous solution, addition of electrolyte controls the relative binding of the two Janus faces of the ellipsoids. Equilibrium self-assemblies include clusters and one-dimensional chains. Direct visualization with two-color confocal microscopy reveals the specificity of the binding between the Janus ellipsoids. The mechanism of the self-assembly is understood through computational studies. We assess scope for reconfiguration of the self-assemblies by application of AC electric fields.

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

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