Capillary Spreading of Liquid Drops on Solid Surfaces

✍ Scribed by Rachid Chebbi; M.Sami Selim

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 227 KB
• Volume: 195
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1997.5136

✦ Synopsis

tact angle condition. Greenspan (9) and Greenspan and Spreading of a liquid over a dry smooth solid surface is analyzed McCay (10) calculated the spreading kinetics by assuming in the case of complete wetting, negligible evaporation, and small the common-line speed to be proportional to the difference Bond and Weber numbers. In the inner region, the approach of between the dynamic and static contact angles. Fitting to V. M. Starov et al. (Adv. Colloid Interface Sci. 50, 187 (1994)) is experimental data is also needed to determine the proportionused and disjoining pressure effects are included. In the core region ality constant. of the drop, both capillary and viscous effects are included to Diez et al. (11) used a similarity solution in combination account for deviations from the constant-curvature profile near with the energy equation. They defined the edge of the drop the inflexion point. The spreading laws for the drop radius, the apex height, and the dynamic contact angle are determined by as the point where the slope is zero. The thickness at the matching the inner and outer solutions at the inflexion point. The rim of the drop was found small but nonzero. The model results are compared with the model of Starov et al. (1994) and does not require any fitting parameter, but the authors recogthe experimental results of J. D. Chen (J. Colloid Interface Sci. nized that small thickness effects become significant far be-122, 60 ( 1988)). The model is not based on any fitting parameter. fore the zero-slope is reached. These effects were not in-