8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.105Theory and simulation of angular hysteresis in sessiledropsMaria Jesus Santos 1 and Juan Antonio White 11 Universidad de Salamanca, Plaza de la Merced, s/n, 37008, Salamanca, SpainThis work tries to reproduce the experimental results obtaines by C. N. N. Lam et al. [1] in ahysteresis cycle of a water droplet deposited on poly(latic acid)-coated silicon wafer. Two methodsare used: on the one hand the resolution of the Young-Laplace equation and on the othe hand asimulation with the program Surface Evolver. In both cases, a friction term is introduced than candescribe adequately the angular hysteresis. The Young-Laplace equation [2] is solved in cylindricalcoordinates. The volume drop evolves in small increments form V i to V f and then decreasing it,at constant speed in both cases. Surface Evolver [3] is a software designed to model surfacessubject to different forces or constraints. Due to its characteristics Surface Evolver es an ideal toolfor the analysis of sessile drops from its interfaces. These are described through a triangulationthat can be modified (refined) and adjusted during the minimization of the energy of the system.Comparision of aur theory and simulation results with experimental data of Lam et al. yieldsexcellent agreement.[1] C. N. C. Lam et al. Advances in Colloid and Interference Science 96, 169 (2002).[2] T. Young, Philos. Trans. R. Soc. London 95, 65 (1805).[3] K. A. Brakke, Exp. Math. 1(2), 141 (1992).105