Clarify the role of adhesion-induced enhancement of the real contact area

Ascertain the contribution of adhesion-induced enhancement of the real contact area to the sliding friction of rubber on surfaces with small roughness and establish how to incorporate this effect into quantitative friction models.

Background

Rubber friction comprises viscoelastic dissipation and an adhesive component that scales with the real area of contact. Adhesion can increase the true contact area, thereby affecting both components of friction.

While experiments on multiscale rough surfaces often suggest negligible macroscopic adhesion, the effect may become important for softer compounds or surfaces with small roughness. A quantitative assessment is needed to resolve when and how much adhesion-enhanced contact area contributes to the overall friction.