Frictional properties of poly(N-polyfluoroalkylacrylamides) Langmuir-Blodgett films

The frictional properties of a series of poly (N-polyfluoroalkylacrylamides) Langmuir-Blodgett (LB) films were investigated to utilize the polymer LB films for a new type of an ultrathin solid lubrication film. The friction coefficients of poly (N-1H, 1H-heptafluorobutyacrylamide) (polyC3F7AA), poly (N-1H, 1H-pentadecafluorooctylacrylamide) (polyC7F15AA), and poly (2-perfluorooctylethylacrylamide) (polyC8F17AA) LB films were determined with a back-to-forth sliding friction meter as functions of loading weight and the number of deposited layers. The friction coefficient for the fluorinated polymer LB films decreases with increasing fluoroalkyl chain length; the coefficients of polyC3F7AA, polyC7F15AA and polyC8F17AA were 0.31, 0.20 and 0.18, respectively. It is concluded that the surface with lower critical surface energy gives smooth surface with lower friction coefficient in the polymer LB films. Moreover, it is found that the lubricating performance of poly(N-polyfluoroalkylacrylamides) LB films is enough with only one layer (LB monolayer) when the lubricating durability can he disregarded. (C) 1999 Elsevier Science S.A. All rights reserved.