In this thesis the forces acting between silica particles in different electrolytes have been investigated by means of the Atomic Force Microscopy (AFM). AFM colloidal probe technique and imaging has been used to understand the effect of surface roughness on dispersion forces. The colloidal probe technique was further employed to study the forces acting between single colloids in aqueous solution of multivalent electrolytes, of ionic liquids and also in presence of pure ionic liquids, where their organizational structure at the silica surface has been elucidated.