Pressure Dependence of the Electrical Resistivity in Polymer Polyaniline

Polyaniline (PAN) was prepared by using a technique of chemical synthesis to obtain the insulating emeraldine base form. And then PAN was doped with toluenesulfonic acid (TSA), HCl, or camphor sulfonic acid (CSA) to protonate it into conducting salt form. The morphologies and electrical property of PAN under atmospheric pressure were investigated. Subsequently, the high pressure using a Bridgman anvil cell was applied on the doped PAN, and the effect of high pressure on the properties of doped PAN was analyzed. At normal pressure, the conductivity of PAN increases as the PH value increases. While at high pressures, the conductivity of PAN increases, and then it becomes independent of pressure. The results indicate that the conductivity of PAN is related to the presence of the polaron band, and the doped PAN under high pressure will be enhanced strongly in conductivity because of overlap of polaron band andπband. However, with the further increase of the applied pressure, scattering mechanisms of carriers limit the conductivity of PAN.