Chemical modifications induced in swift heavy ion irradiated polymers

Swift heavy ions (SHI) have velocities around or above the velocity of K-shell electrons, which corresponds to energies ranging from a few MeV/amu to about 100 MeV/amu. They interact with matter mainly by inelastic collision processes leading to ionisation of the target atoms and excitations of the target electrons: Nearly all of the SHI energy is lost in the electronic stopping power (dE/dx)(e) range. Most of the work concerning SHI effects in materials concern biological matter and materials insensitive to radiation damage processes such as metals or metallic oxides. On the contrary, few studies have been published concerning high (dE/dx)(e) effects in radiolysis sensitive materials such as polymers. This contribution deals with the chemical effects induced by SKI in polymers (mainly poly(vinylidene fluoride), but also other fluorinated polymers, polyethylene, polystyrene..). Several kind of defects are created (unsaturations, crosslinking, stable radicals, chain scission, oxidation...). The influence of irradiation parameters (absorbed dose, ion) is presented. Different evolutions when (dE/dx)(e) increases is observed. Some defects are specific of SHI and thus appear only at high (dE/dx)(e). Some see their yield of creation increased on high (dE/dx)(e) while others are so easily formed that increasing the (dE/dx)(e) does not affect their yield.