Wettability versus roughness: Multi-scales approach

Abstract These authors experimentally investigate the influence of multi-scale roughness on contact angle measurements, and they propose a model combining the Wenzel and Cassie–Baxter equations with the 3D roughness parameters defined by ISO25178. To do this, a generic methodology based on a statistical method (bootstrap and correlation coefficient) is developed and applied to a polypropylene textured femtosecond laser (55 surfaces, ablation depths=5–45 μm and depth/diameter=0.07–0.53). A mixed model is proposed according to the correlations obtained between the contact angle of a plane surface, θ 0 , and a textured surface, θ , with the roughness parameters as the developed surface, S dr , closed hills area, S ha and the closed dales area, S da , with regard to the models of Wenzel and Cassie–Baxter.