Finite element estimation of electrostatic double layer interaction between colloidal particles inside a rough cylindrical capillary: effect of charging behavior

In this paper, we present the electrostatic double layer (EDL) interactions between colloidal particles trapped inside a rough cylindrical capillary based on finite element analysis of the governing Poisson-Boltzmann equation. The effective EDL force between the particles is evaluated for different combinations of charging behavior (constant potential and constant surface charge density) of the particles and the capillary wall. Effect of capillary wall roughness is estimated using a simple model of a rough surface, which assumes the capillary wall to be a periodic function of axial position. The interaction force experienced by the particles was affected significantly by the proximity of the rough capillary wall, the charging behavior of the particles and the capillary wall, as well as the amplitude and frequency of the wall roughness.