Surface Analysis of Plasma-Polymerized Fluorocarbon Films by X-Ray Photoelectron Spectrometry

Abstract

The surface of films deposited from hexafluoroethane and tetrafluoroethylene on plastic and wool textile substrates was analyzed by x-ray photoelectron spectroscopy. The carbon Is spectra obtained from the fluorocarbon surfaces could be resolved into five lines. The three highest binding energy lines were assigned to carbons containing one, two, and three fluorine atoms, respectively. Surface oxidization was detected by the presence of two oxygen Is lines on the surface of the films. Two fluorine Is electron lines were observed on the surface of the films formed from hexafluoroethane on wool. These lines were assigned to fluorine covalently bound to carbon and ionic fluoride. The surface oxygen-fluorine atom ratio was found to vary considerably among the various surfaces analyzed. Fluorocarbon films obtained from plasma polymerization of tetrafluoroethylene contained a significant amount of trifluoromethyl and fluoro-methyl groups on the surface, indicating extensive monomer breakdown in the plasma. The degree of substrate coverage and the chemical structure of the deposited film could be determined from this x-ray photoelectron spectroscopic study.