Effects of self-affine surface roughness on the friction coefficient of rubbers in the presence of a liquid interlayer

Abstract

In this article, we investigate how the friction coefficient is affected by the presence of a liquid layer in between a self-affine rough surface and a sliding rubber surface. The liquid layer will reduce energy dissipation from the small surface asperities and cavities of lateral sizes smaller than the healing length ζ and, therefore, will reduce the coefficient of friction. Significant coefficients of friction are attained for small healing lengths ζ (≪ξ with ξ the in-plane roughness correlation length). Finally, it is shown that the effect of the substrate roughness exponent H becomes less important especially for large healing lengths (ζ⩾ξ).