Linear energy transfer (LET) effects of high energy radiation on polymers

Ion beam irradiation of polymers is the basis of modern technologies concerning, e.g. the generation of microstructures in conjunction with the fabrication of electronic microdevices or the modification of surfaces of foils. In spite of the rapid progress in various applications the knowledge about elementary chemical processes induced by ion beam irradiation of polymers is still incomplete. The paper reviews recently performed work that was devoted to the elucidation of the mechanism of chemical alterations in synthetic polymers. After a general treatment of the dependence of both the LET and the track structure on the particle energy E, ion beam-induced crosslinking is dealt with. Especially treated is the recently discovered ion beam-induced intermolecular crosslinking of poly(methyl phenyl silane). Moreover, G(X) values(100 eV-yields of crosslink formation) measured by various research groups in the case of polystyrene are discussed in some detail with emphasis put on both LET and track structure effects. (author)