Electronic transport in PANI-CSA/PANI-DBSA polyblends

New polyaniline (PANI) blends, PANI-camphor sulfonic acid (PANI-CSA) and PANI-dodecylbenzene sulforric acid (PANI-DBSA) composite films with high room-temperature conductivity (similar to200 S/cm) were prepared. The experimental data show a transition from negative temperature coefficient of resistivity (TCR) to positive TCR at around 210 K. An equation p(T) = a.p(m) exp(- T-m/T)+b.p(0) exp(T-0/T) (1/4) combining 3D variable-range hopping in disordered regions with quasi-one-dimensional metallic conduction in ordered regions has been used, which are consistent well with the resistivity data even from 1.8 up to 370K. It is found that the PANI blends show positive magnetoresistance (MR) from 240 K down to 1.8 K and show negative MR from 240 K up to 350 K, which can be attributed to different dominant conduction mechanisms in different temperature ranges. (C) 2003 Elsevier B.V. All rights reserved.