Wetting and Spreading of Styrene−Butadiene Latexes on Calcite

Abstract

The wetting behavior of individual styrene−butadiene latex particles on the cleavage surface of calcite is described for latexes with glass transition temperatures above and below room temperature. Contact angles of the spread particles, as determined from scanning force microscope images corrected for tip artifacts, were measured. Both types of latex spread with a slight anisotropy, resulting in a continuous variation of the local contact angle by ±6° around the particle edges. Pull-off force measurements were used as a transfer standard to show that the surface energy of the latex particles, after spreading, was the same as that of continuous films made from the same latex. The work of adhesion W, as determined by the Young−Dupre equation, was found to be 80−85 mJ/m2 for the latex with a high glass transition temperature. Lifshitz theory was used to show that nondispersive interactions make a large contribution to W. Individual particles of the latex with a low glass transition temperature had a large v...