Effect of normal load on friction coefficient for sliding contact between rough rubber surface and rigid smooth plane

This study focused on the normal load dependence of the friction coefficient for the sliding friction of a rubber material with a rough surface. A developed friction tester was used to visualize the real contact regions distributed within the transparent contact interface between poly-dimethyl siloxane (PDMS) and glass surfaces. Based on experimental results, an adhesion friction model was developed to explain the normal load dependence of the friction coefficient. This model provides a simple technique that can roughly but easily estimate the real contact area and shear stress without in situ observation of the contact interface.