Abstract
Although Young's equation is widely applied in surface science and engineering, its application in magneto-wetting has not been reported. The nuclear spin processes that dominate liquid surface deformation in magnetic fields remain unclear. Here, we derived an entropic Young's equation where the entropy of a sessile droplet is a function of its cosine contact angle. Subsequently, an equation to calculate changes of contact angle activated by magnetic fields was established using Maxwell's relationship. We (1) further model the Moses and Inverse Moses magneto-wetting processes, (2) reproduce experimental liquid contact-angles in the range of 0 to 8 T with one or maximum two Moses parameters, and (3) replicate the phenomena of water-cluster fragmentation and hydrogen-bond creation reported by molecular dynamic simulation from 0 to 10 T. These results enable a quantitative study of the magneto-wetting process while offering exciting possibilities in electromagnetic-device development, ferrofluids navigation, and invention of portable MRIs. (C) 2021 Elsevier Ltd. All rights reserved.