MOSSBAUER-SPECTROSCOPY OF POLYISOPRENE DOPED WITH I-129

The Mossbauer spectroscopy has been applied to nonconjugated polymer f ilms (1,4-trans-polyisoprene) doped with I-129. At a light doping leve l, most of iodine in the films has been found to be covalently bound t o main chain carbons by breaking the double bonds of the polymer chain . In addition to the covalently bound iodine (Ialpha), a small amount of I-, I3-, and I5- has been observed at the light doping level. The r elative abundance of Ialpha decreases and that of I5- increases at a m edium doping level. At a high doping level, it has been revealed that the major iodine species are Ialpha, I5-, and free iodine molecules I2 . The electrical conduction mechanism in the polyisoprene-iodine syste m has been discussed on the basis of the Mossbauer results.