The Decomposition Mechanism of Perfluoropolyether Lubricants during Wear

The decomposition of perfluoropolyether (PFPE) lubricants is studied by Fourier Transform Infra Red Spectroscopy (FTIR), Thermal Programmed Desorption (TPD), Electron Stimulated Desorption (ESD) and mass spectrometry. Thermal decomposition of perfluoropropyleneoxide (Krytox, Dupont) results in a different set of products than electron decomposition. The electron decomposition of perfluoropolyethers can take place with electrons with energies below the ionization potential of the perfluorinated molecule. This is probably due to the formation of a negative ion resonant state, followed by the dissociation of the molecule into a negative ion and a radical. Mechanical decomposition gives rise to a third product distribution, that bears some similarity to the electron decomposition products.