Abstract
A theoretical study was conducted to investigate the critical condition at which the liquid droplet is sliding down on the inclined plate. The occurrence of sliding is dependent on the width of the droplets from the consideration of force balance in the tangential direction of the plate. The calculation of system free energy showed that the system is in equilibrium during the expansion of the droplet volume. Assuming that the attached surface of droplets to the plated is circular, the critical width was obtained from the condition that the system energy starts to increase. The critical volume was experimentally measured for some kinds of test liquids and plates. The results agree with those calculated from the theory in this study.
