Modeling the rupture of a capillary liquid bridge between a sphere and plane

Abstract

The capillary force due to a liquid bridge, and the breaking of this bridge, are of importance due to the widespread existence of capillary menisci in macro-, micro-, and even nano-scale applications. In this paper, a model was developed to predict the rupture distance between a micro- to nano-sized sphere and a plane. There was good agreement between the theoretical prediction and experimental results for the change in normalized capillary force with separation distance. This partly demonstrates the accuracy and robustness of the model. Based on the model, we found that the rupture distance increased with stronger particle hydrophobicity, increasing particle radius, and increasing environmental humidity. The dependence of the rupture distance on the hydrophobicity of the particle and particle radius was particularly enhanced with nano-sized particles. The model we developed and the observations from this model are helpful in the development of nanotechnology such as the nanoparticle separations, nanoparticle picking up and atomic microscopy manipulations.