HIGH LUBRICATION PERFORMANCE OF TRIBOLOGICALLY ORIENTED FLUOROPOLYMER MOLECULES ANALYZED BY POLARIZED INFRARED MICROSPECTROSCOPY

The molecular structural changes induced in sputtered fluoropolymer film by tribological effects is pursued using polarized micro-Fourier-transform- infrared (micro-FTIR) spectroscopy. Hydrogenation of the carbon radicals produced by CF or CC bond cleavage is detected in the mildly rubbed region, together with Clarge-closed-square signC bond formation. Polarization measurements reveal that a rigid Clarge-closed-square signC-bond-rich framework is oriented along the sliding direction in a hardly rubbed region. This rigid carbon framework involves CF bonds with low polarizability. This structure greatly contributes to stable lubrication with a low friction coefficient, after the fluctuating lubrication characteristics that occur in the early rubbing stage have stabilized. These molecular structures are decomposed into C 3/4 C and Clarge-closed-square signClarge-closed-square signC bonds through further elimination of CF moieties by abrasive hard rubbing by all means. Finally, they extremely decompose into amorphous carbon and metal carbide under severe conditions involving the reactive metals which appear after the film molecules are worn out.