A new model to estimate the Young contact angle from contact angle hysteresis measurements

Beyond the linear model of Schulze et al. [J. Adhes. Sci. Technol. 3 (1) (1989) 39–48], a more comprehensive model for predicting the Young contact angle of rough and chemically homogeneous surfaces from contact angle hysteresis measurements is proposed. This new model incorporates the barrier effect, described by Shuttleworth and Bailey, and the Wenzel model as well. Both the linear and nonlinear models were evaluated using a thermoplastic polyether-based elastomer and PDMS and two liquids. The elastomer surfaces were textured on purpose at differing degrees of roughness. Both models provided similar values of Young angle, although the nonlinear model also provided information about the distribution of practical metastable configurations around the most stable equilibrium configuration. Despite the linear model showed slightly better goodness-of-fit and minor uncertainties in its parameters, the nonlinear model is more reliable and theoretically consistent.