“…It can be viewed as the force in the plane of the surface that must be exerted perpendicular to each unit length of edge to keep the surface from spreading (Smith, Van Ness, & Abbott, 2001). Skaar and Babiak (1982) used the spreading pressure concept as the driving force in developing transport models during diffusion in porous solid. The spreading pressure is not subject to direct experimental measurement; it can be estimated using an analytical procedure such as described by (Fasina, Ajibola, & Tyler, 1999) from the relationship:…”