Electron stimulated C-F bond breaking kinetics in fluorine-containing organic thin films

By monitoring the variation in the fluorine content and the distribution of CFx (x = 0-3) species in a semifluorinated self-assembled monolayer (CF-SAM) upon prolonged X-ray irradiation, the electron stimulated C-F bond breaking kinetics in fluorine-containing organic films has been determined. At short irradiation times, X-ray irradiation induced changes in the film's chemical composition are consistent with the presence of C-F, C-C and S-Au bond cleavage events. In contrast, C-F bond breaking is identified as the dominant kinetic process for longer X-ray exposures. The kinetics of X-ray induced defluorination are consistent with a first-order decay process mediated by a series of consecutive C F bond breaking events (e.g., CF --> C) whose rate constants are in excellent agreement with a stochastic model of defluorination. (C) 2002 Elsevier Science B.V. All rights reserved.