Capillary Torque on a Particle Rotating at an Interface.

ABSTRACT: Small particles attach to liquid-fluid interfaces due to capillary forces. The influence of rotation on the capillary force is largely unexplored, despite being relevant whenever particles roll at a liquid-fluid interface or on a moist solid. Here, we demonstrate that due to contact angle hysteresis, a particle needs to overcome a resistive capillary torque to rotate at an interface. We derive a general model for the capillary torque on a spherical particle. The capillary torque is given by M = γRLk(cos Θ_R - cos Θ_A), where γ is the interfacial tension, R is the radius of the particle, L is the diameter of the contact line, k = 24/π³ is a geometrical constant, and Θ_R and Θ_A are the receding and advanci

SUBMITTER: Naga A 

PROVIDER: S-EPMC8280771 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature