Effects of frictional force on the formation of colloidal particle monolayer during drying─Study using discrete element method

Abstract

This paper presents the effect of frictional force between colloidal particles and a solid substrate on the formation of particle monolayer by a numerical simulation. Discrete Element Method is employed to simulate the dynamics of colloidal particles trapped in liquid film. Forces such as capillary immersion force, van der Waals force and frictional force are included in the simulation model. Isotropic ordering factor and non-dimensional boundary length are introduced to quantify the structures of colloidal particles. In the case where the diameter of colloidal particles ranges from 100nm to 1000nm, the monolayer structures depend strongly on the frictional constant between a particle and a solid substrate. On the other hand, in the case where diameter is about 10nm, large domains of hexagonal close-packed structuers are formed because of the Brownian force.