The rigorous derivation of Young, Cassie–Baxter and Wenzel equations and the analysis of the contact angle hysteresis phenomenon

The rigorous derivation of Young, Cassie–Baxter and Wenzel equations carried out in the framework of the unified thermodynamic approach is presented. Wetting of rough surfaces controlled with external stimuli is treated. Areas of validity of Cassie–Baxter and Wenzel approaches are discussed. General properties of the contact angle hysteresis are investigated on the same thermodynamic basis.