A Thermodynamic Model for Wetting Free Energies from Contact Angles

A simple thermodynamic model for determining the wetting free energy of a small, sessile drop spreading on a solid surface has been derived by assuming that the process can be treated as adsorption. According to the model, free energies are expected to be small for large contact angles and increase exponentially as contact angles tend toward zero. Wetting free energies calculated using contact angles taken from the literature for various liquid−solid pairs agreed reasonably well with the bond strengths measured by other experimental techniques.