Young's equilibrium contact angle on rough solid surfaces. Part I. An empirical determination

Abstract

—The influence of the roughness of solid surfaces on the contact angle hysteresis, Δ, was studied for low-energy solids (paraffin, PTFE, PMMA) using pure liquids. Taking Δ as dependent on the roughness, the contact angle data can be linearly approximated. The value of Δ = 0 is considered as the equilibrium contact angle e known from thermodynamic considerations. The slopes of these straight lines form another linear function of the corresponding e. Hence e can be calculated from a single measurement of a,e and r,e for the systems under consideration.