CHEMICAL-REACTIONS AND PHYSICAL PROPERTY MODIFICATIONS INDUCED BY KEV ION-BEAMS IN POLYMERS

Factors influencing the chemical modification of polymers under ion bombardment are discussed. The chemical state and the electronic structure of ion-bombarded polymers are studied by XPS and REELS techniques. Ion bombardment of polymers is shown to induce well defined reactions involving the gradual modification of the original chemical structure within well defined fluence ranges, characteristic for each type of chemical reaction. The rate and the relative yield of the bombardment induced chemical reactions are shown to depend on the primary chemical structure of the bombarded polymers as well as on the total ion deposited energy, fluence and energy deposition mechanism. Such a dependence is discussed for some ion induced reactions in polyvynilpyridine (PVPY), polyethersulphone (PES). It is shown that polymer samples bombarded at very high fluence (1015-1016 ions/cm2) still keep "memory" of their primary stoichiometry and chemical structure showing spectroscopic characteristics similar to those of hydrogenated amorphous carbons. A number of cases are discussed in which the physical and electronic structure of the "carbonaceous" materials obtained depend upon the energy deposition mechanisms. © 1990.