Depth dependence of alkali etching of poly(tetrafluoroethylene): Effect of x-ray radiation

Using Rutherford backscattering spectroscopy (RBS), the authors have shown that defluorination due to alkali etching of poly(tetrafluoroethylene) (PTFE or Teflon) extends to a depth of at least 3,000 angstrom. Equivalent alkali etching after irradiation with Mg Kα X-rays gives no indication of defluorination within the depth resolution of RBS (150 angstrom); the RBS spectrum is identical with that of a reference PTFE sample. In contrast, X-ray photoelectron spectra (XPS) reveal comparable defluorination for both irradiated and nonirradiated samples. given the sampling depth of XPS and the depth resolution of RBS, this limits the defluorination depth of the irradiated surfaces of PTFE to between 30 and 150 angstrom