Fluorocarbon/hydrocarbon interactions and frictional surface forces

Alumina-adsorbed hydridosiloxane polymers are used as a "base" for further chemical modification and determination of intersurface frictional coefficients. The stability of this base layer is found to be particularly sensitive to the presence of moisture. Sedimentation experiments suggest that the final densities of compacts produced from hydridosiloxane-coated alumina particles are independent of the range of molecular weights used in this study. Subsequent reaction of the base layer with silanol-terminated trifluoropropylsiloxane and polydimethylsiloxane tails yielded considerable differences in sediment density and character in spite of similar molecular weights. Use of a frictional surface forces apparatus suggests that this phenomenon is not due to a frictional or lubricative effect induced by the fluorine-containing component. © 1993.