Interaction of alcohols with a-CHx films

Temperature programed desorption has been used to study the desorption kine tics and desorption energies of a set of alcohols and fluorinated alcohols adsorbed on an a-CHx film. The alcohols serve as models for the hydroxyl en d groups of Fomblin Zdol, the lubricant most commonly used with the amorpho us carbon overcoats sputtered onto the surfaces of magnetic data storage di sks. Temperature programed desorption has been used to measure the desorpti on energies of the alcohols over a range of coverages and to compare the de sorption energies of fluorinated and hydrocarbon alcohols. The desorption e nergies are all coverage dependent and decrease with increasing alcohol cov erage. This is believed to be due to heterogeneity of the a-CHx films surfa ce. In all cases the low coverage desorption energies of the fluorinated al cohols were found to be higher than those of their hydrocarbon counterparts . The implications of this observation are that the interaction of the alco hols is through hydrogen bonding of the hydroxyl groups to the a-CHx films. This conclusion is consistent with that reached in a similar study of the adsorption of alcohols to the surfaces of a-CNx films. (C) 2000 American Va cuum Society. [S0734-2101(00)05005-3].