Low-Friction Surfaces Prepared Using a Water-Soluble Amphiphilic Polymer

Abstract

Aqueous lubrication has received considerable attention not only due to the benefits for energy efficiency and low environmental burden but also due to the importance in designing low-friction surfaces of biomaterials. The excellent fluidity of water is obtained even in molecular scale confinement between surfaces (this is not the case for oil lubricants), which is the major origin of low friction in boundary lubrication. However, this high fluidity may result in the easily squeezed out of water from the sliding interface that leads to surface damage. Selecting suitable chemicals as additives is one of the solutions for this problem ; the impact of using water-soluble polymers as additives for aqueous lubrication was investigated. We found that some silicone-type amphiphilic polymer formed an adsorbed layer on surface and exhibited excellent lubricity (friction coefficient of the order of 10^－5), due to the easy slippage of monomolecular layer of water between the adsorbed layers.