Tribological behavior of grafted polymer gel nanocoatings

A robust molecular lubrication layer on a silicon surface has been fabricated from a grafted polymer gel with thickness below 10 nm. A functionalized rubber-glassy block-copolymer was chemically grafted to a silicon oxide surface and its tribological performance was enhanced by vapor saturation with a minute amount of alkyl-based paraffinic oil. A combination of tribological measurements and Auger electron spectroscopy was used to monitor the polymer layer wearing behavior. We observed that unlike a "dry" polymer layer and a classic "boundary lubricant", an alkylsilane self-assembled monolayer, the polymer gel coating exhibited a steady friction response, a very low value of the coefficient of friction, and possessed much higher wear-resistance.