ORDER OF 3-PHASE (SOLID-LIQUID-GAS) CONTACT LINE TENSION AS PROBED BYSIMULATION 3-PHASE CONTACT LINE EXPANSION ON SMALL HYDROPHOBIC SPHERES

Expansion of the three-phase (solid-liquid-gas) contact line on the su rface of silanated glass spheres was experimentally studied by means o f a CCD high-speed video technique. The dependence of the central angl e (measured at the particle center) of the contact line on time was de termined. This dependence was theoretically simulated. Results of this simulation show a strong effect of line tension on the kinetics of th e three-phase contact expansion. Order of the line tension (mu J/m) is the same as that determined by A. W. Neumann and co-workers for simil ar hydrophobic surfaces by means of different techniques. (C) 1997 Aca demic Press.