CAPILLARY SPREADING OF LIQUID-DROPS ON SOLID-SURFACES

Spreading of a liquid over a dry smooth solid surface is analyzed in t he case of complete wetting, negligible evaporation, and small Bond an d Weber numbers. In the inner region, the approach of V. M. Starov et al. (Adv. Colloid Interface Sci. 50, 187 (1994)) is used and disjoinin g pressure effects are included. In the core region of the drop, both capillary and viscous effects are included to account for deviations f rom the constant-curvature profile near the inflexion point. The sprea ding laws for the drop radius, the apex height, and the dynamic contac t angle are determined by matching the inner and outer solutions at th e inflexion point. The results are compared with the model of Starov e t al. (1994) and the experimental results of J. D. Chen (J. Colloid In terface Sci. 122, 60 (1988)). The model is not based on any fitting pa rameter. (C) 1997 Academic Press.