Using colloids to probe the physics of atomic systems:From the deformation of crystals to the formation of glasses - Shreyas Gokhale

Thu, Dec 4, 2014, 2:00 pm to 3:30 pm
Joseph Henry Room
Over the last fifteen years or so, suspensions of micron-sized colloidal particles have emerged as promising model systems to explore diverse atomistic phenomena ranging from dislocation dynamics in crystals to shear transformation zones in glasses. The large size and slow dynamics of colloidal particles makes it possible to visualize their motion with single particle resolution in real time using optical means. This ease of visualization not only enables experimental verification of theoretical predictions that are prohibitively difficult to test in atomic systems, but also opens the door for unearthing hitherto undiscovered phenomena. I will illustrate these points using two examples. First, I shall demonstrate how the anisotropic enhancement of grain boundary interface fluctuations in sheared colloidal polycrystals and its culmination in directional grain growth can be probed using a combination of confocal microscopy, rheometry and optical Bragg diffraction microscopy. Secondly, in the context of the dynamical facilitation theory of glass formation, I shall highlight how pinning a configuration of colloidal particles using holographic optical tweezers or manipulating the particles’ shape can be instrumental in validating theoretical scenarios of the glass transition. Shreyas Gokhale Indian Institute of Science