Ion beam induced conversion of PVC into a conducting polyene

The irradiation of PVC films with a beam of 1 MeV α particles induces the dehydrochlorination of the polymer molecule leading to the formation of sequences of conjugated double bonds. Mass spectrometry of the fragments desorbed during irradiation shows two main peaks that results from H2 and HCl release. The kinetics of the HCl peak is in accordance with a model of H and Cl atoms liberation to form the HCl molecule in the bulk according to the usual radiolysis scheme. The optical absorption spectrum shows the formation of conjugated segments involving 8 double bonds for a fluence of 1015 He+ / cm2, whereas the dehydrochlorination rate has reached a low stable value. Implications for the production of new electronic properties are adressed.