Ithaca College

Physics Department Seminar Series - Fall 2011

Please join us for a talk entitled

Entropy and Geometry: From Directed Self-Assembly to Phase Behavior of Custom-Shaped Colloids with Thomas Mason of UCLA

We develop and exploit anisotropic roughness-controlled depletion attractions to direct self-assembly, to study equilibrium phase behavior, and to examine jamming of monodisperse custom-shaped microscale partic dispersed in a viscous liquid. By observing two different systems of hard regular pentagonal platelets and hard square platelets, in which the platelets are confined yet diffuse in a plane, as a function of particle density using optical video particle-tracking microscopy, we reveal rich structural disorder-order, order-order, and order-disorder transitions, as well as rotational and translational jammed states that have dynamics reminiscent of glasses. Brownian squares in 2-d undergo isotropic-hexagonal rotator crystal-rhombic crystal transitions as the particle density is increased, whereas Brownian pentagons undergo an interesting order-disorder transition to a frustrated state at the highest densities, reflecting spatial frustration, since pentagons cannot fully tile a plane. Overall, these model colloidal systems reveal interesting and beautiful equilibrium and non-equilibrium physics that arise from the simple yet subtle combination of entropy and geometry.

Tuesday, September 13th at 12:10 pm in CNS 204

Pizza and Refreshments will be available for $1.

Please bring your own cup.

Remember to Recycle, Reuse, Reduce.

Individuals with disabilities requiring accommodations should contact the Physics Department at jackerman@ithaca.edu. We ask  that requests for accommodations be made as soon as possible.