Motion of micro- and nano- particles interacting with a fluid interface

Abstract

In this article, we review both theoretical models and experimental results on the motion of micro-and nanoparticles that are close to a fluid interface or move in between two fluids. Viscous drags together with dissipations due to fluctuations of the fluid interface and its physicochemical properties affect strongly the translational and rotational drags of colloidal particles, which are subjected to Brownian motion in thermal equilibrium. Even if many theoretical and experimental investigations have been carried out, additional scientific efforts in hydrodynamics, statistical physics, wetting and colloid science are still needed to explain unexpected experimental results and to measure particle motion in time and space scales, which are not accessible so far.

Drag on a spheroidal particle at clean and surfactant-laden interfaces: effects of particle aspect ratio, contact angle and surface viscosities

“…(2016) and Villa et al. (2020) for hydrophilic particles, (), and for or equivalently, , where is defined as …”

Interfacial flow around a pusher bacterium

“…Furthermore, interfaces can have complex surface stresses including surface viscosities and Marangoni stresses owing to surfactant adsorption (59,60). These effects are associated with anomalous drag (61)(62)(63)(64)(65)(66) and divergence-free motion which further constrain the interfacial flow (39,(67)(68)(69). While such factors have been shown to dramatically restructure flow around passive colloids at interfaces (70), their impact on the flow field generated by swimmers is unknown.…”

Microparticle Brownian Motion near an Air-Water Interface Governed by Direction-Dependent Boundary Conditions

“…For a particle moving in close vicinity of the interface these broken symmetries express themselves in a tensorial and space dependent particle drag the values of which are determined by boundary conditions (BC) at the interface. Theoretical expressions for the translational mobilities are well known for sphere motion parallel and perpendicular to the interface in both cases of slip and no-slip BC [1,2,3,4] (see Appendix A for a report of the models). In the case of a water-air interface, the particle drag is expected to be governed by slip BC as predicted for free fluid surfaces [1,3].…”