Emission of volatile degradation products from polymers irradiated with heavy ions to different fluences
Polyimide (Upilex), polyethyleneterephtalate, polystyrene and polyethylene were irradiated with 20-200 KeV C+, N+, F+, Ar and Xe+ ions to the fluences up to 10(17) cm(-2) and the depth profiles of hydrogen and oxygen atoms in the polymer surface layer were determined using standard Rutherford Back-Scattering (RBS) and Elastic Recoil Detection (ERD) techniques. The H and O depth profiles are structureless with no local extremes and with the concentration monotonically increasing from the sample surface to the bulk value typical for pristine polymer. The H and O contents in the irradiated surface layer remain unchanged up to a critical fluence, which is a decreasing function of the energy density deposited by an ion. Then they decline rather rapidly and converge to 50-70% of their original values of unirradiated polymer. The decline rate is roughly the same for all ion/polymer combinations regardless of the ion mass and energy.