A model for a liquid drop spreading on a solid surface

This paper presents an overall energy balance (OEB) method for modelling the spreading process of a liquid drop on a solid surface. This method combines surface physics and fluid mechanics and contains only one adjustable parameter. Using the de Gennes model for the viscous force of a moving contact line and the OEB method, this novel theoretical spreading model accounts for the inertial, viscous and gravitational forces, the interfacial tensions and the contact angle of the solid-liquid-fluid system. A computer program for implementing the spreading model is developed. A set of measured spreading data of silicone liquid drops on a soda-lime glass plate is used to verify the model predictions for the spontaneous spreading case. The comparison shows that the simple spreading model presented in this paper can predict well the spontaneous spreading of a liquid drop on a solid surface. (C) 1998 Elsevier Science B.V. All rights reserved.