(51a) Dynamic Interfaces for Multiscale Control of Colloidal Interactions

Colloidal emulsions and lipid-coated particles contain fluid interfaces where bound macromolecules can diffuse laterally along the surface. When two colloids come into contact, the lateral reorganization of surface species such as tethered polymers on each individual colloid can give rise to a `dynamic two-body potential' that relaxes as a function of the colloid-colloid contact time. This dynamic pair potential is a unique product of the competition of time scales between the relaxation of surface species and colloidal motion due to Brownian diffusion or external forcing. In this work, we interrogate this molecular-to-mesoscale multiscale coupling of interfacial and colloidal suspension dynamics using a combination of theory and coarse-grained molecular dynamics simulations. We find that interface modulation of surface mobility enables exquisite control over the colloidal microstructure and gives rise to unusual bulk rheology in the presence of hydrodynamic fluid flows.