Ion Beam Enhanced Electrical Conductivity in Polymers

We have used proton, alpha, nitrogen and oxygen particles at energies between 1 to 8.5 MeV to modify the conductance of various polymers with linear molecular chain structure and polymers with two dimensional networks of chemical bonds, specifically benzene ring. The beam energy and the beam current, 100 pA to 30 nA, for each species were selected to deliver maximum electronic stopping power in a predetermined depth and area. The electrical conductance of the bombarded volume in each polymer was measured in situ and changes were recorded to be between 10- 13 Siemens before bombardment to 0.1 Siemens after bombardment depending on the total energy deposited in a given volume of the polymers. The carbonized volumes were analyzed by Raman microprobe spectroscopy which showed that the strongest graphitic (G-line) and distorted (D-line) Raman signals observed were from the volume with the highest conductance.