A modified method for computation of contact angles of aqueous electrolyte solutions on quartz

A modified technique is proposed for computing contact angles of aqueous electrolyte solutions on charged solid surfaces with varying degrees of hydrophilicity. Along with earlier equations for molecular and structural forces, the modified method also uses a more general expression for electrostatic forces, which is not confined to the condition of a low solution concentration. The resultant expression allows us to compute contact angles for aqueous solutions in a wide range of concentrations and pH values. The applicability range is determined for the previously obtained simplified expression describing electrostatic forces in films. An approach to computer search for parameters of structural forces of hydrophilic repulsion and hydrophobic attraction in wetting films on the basis of experimental values is developed.