Colloid structural forces in thin liquid films

Abstract

In recent years the interest in non-DLVO forces has continuously increased because of their tremendous importance for dispersion stability. Colloid structural forces appear when thin liquid films are formed from concentrated suspension of monodisperse particles (micelles, latex particles, proteins). At low particle volume fraction these oscillatory forces degenerate into the depletion attraction. We propose simple semiempirical formulas describing the oscillatory structural force and energy. Their comparison with available experimental data and theoretical calculations shows a good agreement. Depending on the conditions (particle size, concentration, charge, etc.) the oscillatory structural forces may stabilize or destablize the thin films and dispersions (emulsions, suspensions). The role of different factors such asd temperature, electrolyte, and micelle concentrations, etc., are treated in a unified way and can be explained by the change of the effective particle volume fraction.