Mesoscopic simulation of liquid bridge spreading under squeezing of parallel plates

Abstract

The spreading behaviour of a droplet under squeezing between parallel plates is seen in the adhesion of microelectronic components and the lubrication of human joints, which is a process involving complex micro-scale flow behaviours such as three-phase contact line movement. In this study, a many-body dissipative particle dynamics method is employed to account for this process. The method has been first validated by comparing with Cox's theory of contact lines. Two stages have been identified during the process of squeezing: a contact line retraction state and a symmetrical spreading state, which can also be reflected by different decreasing rates of free energy. The combined effects of squeezing velocity and plate's wettability on the appearance of the first stage have been investigated, showing that a large enough squeezing velocity and a hydrophobic enough substrate will lead to no contraction of the contact line. This study provides a valuable tool to explore the possibility of controlling the droplet squeezing behaviour and thus is helpful for optimizing the adhesion and lubrication process.