Patent ID: 7514150

Claim:
A method of lubricating two sliding surfaces, wherein the two sliding surfaces slide against each other and are in a device or machine, wherein at least one surface is a charged surface, comprising administering between the two surfaces a lubricating composition, wherein the lubricating composition comprises a graft copolymer comprising a polyionic backbone that has a net positive or negative charge at neutral pH and side chains, and an aqueous medium, wherein the side chains are formed by a polymer consisting of a first monomer (A), wherein the polyionic backbone is formed by a polymer consisting of a second monomer (B), wherein the polyionic backbone adsorbs onto the charged surface to produce a lubricated surface, wherein the side chains do not bind with the charged surface, and wherein the resulting lubricated surface has a lower friction coefficient between the lubricated surface and the second sliding surface than the coefficient of friction between the charged surface and the second sliding surface in the absence of the lubricating composition.