Shear mechanical characterization of a liquid bridge between two parallel plates via Surface Evolver simulation

<p indent="0mm">Liquid bridge shear behavior is widely present in rough interface contact, particle aggregation and synthesis, microchip self-assembly and other mechanical, chemical industry, environmental and biological related fields, which has a significant impact on the service performance of associated systems and equipment. In this paper, the evolution of meniscus contour and solid-liquid interfacial force of a confined liquid bridge between two parallel plates under shear is investigated by using Surface Evolver software simulation. A dual truncated cone theory model is established based on the principle of minimum energy, and the model results are compared with the simulations. The results show that the contact angle hysteresis and tangential force increase linearly with the growth of the bridge shear displacement, while the normal force decreases monotonically as a quadratic function. The tangential force of the liquid bridge exhibits an increasing trend with increasing liquid volume or lowering the vertical space between the two flat plates due to the combined effects of the neck radius and contact angle hysteresis. With the increasing spacing between the two flat plates, the normal force changes in a decreasing and then increasing manner depending on the vertical component of surface tension and the relative magnitude of the pressure difference between the inside and outside of the meniscus. While the dual truncated cone theory model adequately captures the overarching trend in liquid bridge force, it simplifies the real meniscus contour, thus introducing a certain gap between the theoretical predictions and simulated outcomes. This gap can be mitigated by incorporating a dimensionless shape factor, with values closer to 1 indicating a more precise representation of the model.