The interaction of CF3CH2OH and (CF3CF2)(2)O with amorphous carbon films

Fluorinated alcohols and fluorinated ethers adsorbed on carbon films have b een studied in order to model the surface chemistry of Fomblin Zdol lubrica nts on the carbon-coated surfaces of magnetic data storage media. The model compounds used were 2,2,2-trinuoroethanol (CF3CH2OH), which is representat ive of the end groups of Fomblin Zdol, and perfluorodiethylether (CF3CF2)(2 )O, which represents the main chain of Fomblin Zdol. Temperature-programmed desorption (TPD) spectroscopy was used to measure the desorption energies of these compounds on a variety of different carbon films. Desorption energ ies were measured on amorphous hydrogenated carbon (a-CHx), amorphous nitro genated carbon (a-CNx), cathodic are carbon (CAC), and ion-beam sputtered c arbon (IBC). On all carbon film surfaces the desorption energy of CF3CH2OH is higher than that of (CF3CF2)(2)O. The desorption energy of CF3CH2OH is h igher on the a-CNx films than on the other carbon films; however, the desor ption energy of (CF3CF2)(2)O does not depend on the type of carbon. Finally , the desorption energies are dependent upon CF3CH2OH and (CF3CF2)(2)O cove rage, indicating that the carbon films are heterogeneous and expose binding sites with a range of affinities for adsorption. Systematic measurements o f the desorption energies over a range of coverages have been used to map o ut the heterogeneity of all the carbon films.