Rheological effects of rough colloids at fluid interfaces: An overview

Because of the capillary interactions arising from surface corrugation, rough particles at fluid interfaces often exhibit intricate rheological responses to interfacial deformations and material flows, challenging the conventional physicochemical and thermodynamic concepts that were typically applied in bulk suspensions. Although such rheological responses have been widely applied in industrial processes (i.e. crude oil recovery) and some biological systems (i.e. the dynamics of lung alveoli), studies on their physical mechanisms are not summarized systematically. In this work, we present an overview of the rheological effects of rough particle-laden interfaces, where the influences of particles’ softness and geometric roughness are emphatically discussed. We also point out that, relevant rheological effects can be strongly affected by a competition between the particles’ capillary attractions and frictional forces. Potentially, integrating experiments and simulations from a mesoscale perspective would gain deeper insights into the rheological properties for a quasi-2D system.