Francis Henry Ruddy

Ion-induced conductivity in poly (phenylene sulfide)

New data on the production of electrical conductivity in poly(phenylene sulfide), PPS, by ion irradiation are presented. These and previously reported PPS data are investigated in the framework of a theoretical semiempirical model that relates observed conductivity to parameters associated with the deposition of energy in the polymer by the bombarding ions. It is shown that the onset of conductivity with increasing ion dose is dependent on overlap of individual ion damage regions. A straight line relationship is obtained between log of the ion stopping power and log of the effective overlap radius of the ion damage regions. Furthermore, the magnitude of the values of effective overlap radii are consistent with physical observations and theoretical predictions. At higher ion doses, the rapid increase in conductivity appears to be consistent with a multistage reaction mechanism for the production of conducting species in the polymer. A universal curve of conductivity as a function of dose above threshold dose is seen to fit all of the PPS data up to a dose of a factor of 50 above threshold. This curve and the predictable behavior of the threshold dose allow the selection of ion/dose combinations to produce a desired conductivity.