Chemical reactions induced in polymers by keV ions, electrons and photons

Polyvinylcarbazole, polyvinylpyridine and polyethersulphone films have been bombarded with 150 keV Ar+ ion beams and the midified surfaces have been characterized chemically by ESCA and REELS (reflection electron energy loss spectroscopy). In the explored fluence range (5 × 1012−1 × 1016 ions cm−2), several types of chemical reactions, such as dehydrogenation, loss of heteroatopms, loss of aromaticity via ring opening, reduction, etc., heve been shown to occur, depending on the chemical structure of the pristine system. For the polyethersulphone, a comparison of the chemical effects produced by electrons, photons and ion beams of comparable energy (∼1 keV) and fluence (1015−10−16 ions cm−2) also has been reported. The results are discussed in terms of energy deposition mechanisms, as well as chemical grounds. In particular, they allow a further assessment to be made of the field of chemical reactions induced by ion beams. Furthermore, they show that for a given dose the chemical modification of a polymer surface by an ion beam is much greater than that expected for electrons or photons.