The MRSEC holds seminars presenting research at the frontier of Bioinspired Soft Materials. The seminars are targeted towards graduate students and other researchers in the field, although everyone is invited to attend. As the topic is highly interdisciplinary, seminars are designed to be accessible to a wide range of backgrounds.
The seminars take place on Thursdays at 4PM on Zoom.
Organizer: John Berezney (Dogic/Fraden Lab Postdoc)
September 24, 2020
Daniel Blair, Georgetown University
Abstract: In this talk I will discuss our recent results on the microscopic physical origins of shear thickening in two vastly different materials: colloidal suspensions and active gels. In the first part of my talk, I will introduce a method we have developed that allows us to resolve the spatial distribution of stresses in sheared soft-materials, known as Boundary Stress Microscopy. We have applied this technique suspensions undergoing continuous and discontinuous shear thickening. I will present our results on the existence of clearly defined dynamically localized regions of substantially increased stress that appear intermittently at stresses well above the applied stress. Surprisingly, we find that these spatially distinct and dynamic phases account quantitatively for the observed shear thickening seen in sheared colloidal dispersions (e.g. Oobleck). In the second part of my talk I will discuss our results on the rheology of active matter. Our system is composed of microtubules and kinesin motor proteins that self-assemble to form complexes that propel themselves through the fluid. What results is a dramatic increase in the viscosity of the material with applied shear rate.
October 15, 2020
Linda Hirst, University of California Merced
October 29, 2020
Rudolf Oldenbourg, Marine Biological Laboratory
November 12, 2020
Miranda Holmes-Cerfon, New York University