Heat treatment of polyacrylonitrile (PAN) leads to products with semiconductor to metal-like conductivities. The electrical properties of these-materials are further modified by ion implantation. It is noted that the conductivity (∼10^?7 (Ω cm)^?1) of heat-treated PAN at 435 °C (PAN435) increases upon ion implantation with arsenic reaching a maximum value of 1.4 × 10^?1 (Ω cm)?1 at a dose of 5 × 1016 ion cm?2 and energy of 200 keV. On the other hand, ion implantation of the more conducting heat treated PAN at 750 °C (PAN750) leads to a decrease in the electrical conductivity of the material. The data also indicate that the decrease in conductivity observed after implantation of PAN750 is due to the breakup of the graphite-like extended electronic states. The temperature dependence of conductivity provided further information on the structures of the pyrolyzed and of the ion-implanted samples. Whereas the conductivity temperature behavior of PAN750 is consistent with the Cohen-Jortner model for transport in inhomogeneous and disordered solids, the ion-implanted sample (PAN750I) displays a behavior which can be described most adequately in terms of a variable range-hopping conduction mechanism. © SAGE Publications 2011.

Title

High Performance Polymers

Publisher

SAGE

Publisher Country

United States of America

Indexing

Thomson Reuters

Impact Factor

1.047

Publication Type

Prtinted only

Volume

23

Year

2011

Pages

417-423