SIMULATION OF CONTACT-ANGLE HYSTERESIS ON CHEMICALLY HETEROGENEOUS SURFACES

A quasi-steady-state simulation of contact-angle hysteresis is present ed. The model system consists of a two-dimensional drop on a smooth bu t chemically heterogeneous solid surface. The changes in the free ener gy of the system, the contact angle, and the size of the base of the d rop are followed as its volume increases or decreases. The simulated c ontact angle hysteresis, including discontinuous changes in the contac t angle and the size of the base of the drop, are shown to be very sim ilar to typical experimental observations. In addition, the dependence of receding and advancing angles on the energy available for overcomi ng energy barriers is illustrated. (C) 1996 Academic Press, Inc.