23.04.24 - Sebastien Groh

Nonequilibrium relaxation of responsive colloids

Responsive colloids can undergo substantial changes such as state, shape, charge density or electric dipole in response to an external stimulus. While these transformations are critical at the level of the individual particle, they also influence the collective behavior and dynamics of a large collection of interacting colloids. In the first part of the talk, we will introduce a mean-field dynamical density functional theory to study the nonequilibrium dynamics (relaxation) of a colloidal dispersion in time-dependent external fields. Specifically, we consider soft Gaussian particles with a bimodal size distribution between two confining walls with time-dependent (switching-on and off) external gravitational and osmotic fields. We find interesting relaxation behavior of the systems in excellent agreement with particlebased Brownian dynamics computer simulations. In particular, we find time-asymmetric relaxations of integrated observables (wall pressures, mean size, colloidal liquid center-of-mass) which are tuneable by the ratio of translational and conformational diffusion time scales. In the second part of the talk, we will discuss preliminary results on the relaxation of microstructured core-shell microgel monolayers under external compression protocols.