Influence of unforced dewetting and enforced wetting on real contact formation and friction behavior between rubber hemisphere and glass plate during contacting and sliding processes

The influences of unforced dewetting and enforced wetting on real contact formation and friction behavior between a rubber hemisphere and a glass plate were analyzed during contacting and sliding processes under lubrication supplied by mixtures of water, ethanol, and glycerol. Unforced dewetting was quantified by the characteristic dewetting velocity that related to the spreading coefficient and lubricant viscosity, while enforced wetting was determined by the contacting and sliding velocities. The real contact area and friction coefficient correlated positively with the ratios of the characteristic dewetting velocity to the contacting and sliding velocities, respectively, depending on the time period.