Lateral force microscopy study of the friction between silica surfaces in electrolyte solutions

Lateral force measurements between a polished silica wafer and a colloidal silica particle in monovalent electrolyte solution environment (LiCl, NaCl, CsCl) were performed using an Atomic Force Microscope (AFM). Analysis of the friction versus load data, in LiCl case, indicates that increasing the electrolyte concentration, the intensity of the friction force decreases. The effects of the counterions on lateral forces show that friction coefficients gradually decrease from pure Dl water to 1.0M LiCl. Lateral forces versus scan rate graphs show a typical behavior for all investigated systems: transition and saturation region. These results are consistent with the idea that strongly hydrated ions have a lubrication effect in silica-silica interactions.