Theory of hydrostatic lubrication for two like-charge polymer hydrogel coated surfaces

Abstract

It is argued on the basis of a solution of the Poisson–Boltzmann equation and scaling arguments that two hydrogels in contact should be separated by a thin fluid layer, which is likely to be responsible for their excellent lubricating capability, until the gels are under sufficient load to reduce their thicknesses down to the thickness at which the fluid, with which the gel is swollen, is driven out. The observed velocity dependence of the friction is discussed on the basis of this model.