Friction of Gels

Abstract

The sliding friction of various kinds of hydrogels has been investigated, and it has been found that the frictional behaviors of these hydrogels do not conform to Amonton's law F = μW, which well describes the friction of a solid. Instead, the friction force F of the gel shows slight dependence on the load W in the investigated load range, while it strongly depends on the sliding velocity. Additionally, the frictional coefficient μ of the gel reaches a value as low as ∼10-3, which is smaller than those observed in solid materials.