ELECTRICAL-TRANSPORT IN CONDUCTIVE BLENDS OF POLYANILINE IN POLY(METHYL METHACRYLATE)

The electrical transport properties of solution-processed conducting p olyblends of polyaniline-camphor sulfonic acid (PANI-CSA) in poly(meth yl methacrylate) (PMMA) are investigated for PANI-CSA over the full ra nge of volume fractions (f) above the percolation threshold. The posit ive temperature coefficient of resistivity at high temperature and the linear temperature dependence of thermoelectric power indicate that, because of the phase-separated network morphology, the microscopic tra nsport properties of PANI-CSA in the blends remain nearly unchanged by dilution. The low temperature resistivity indicates transport by gene ralized variable range hopping, rho(T) = rho0exp[(T0/T)gamma]. A syste matic change in gamma is observed as a function of dilution; gamma inc reases from approximately 1/3 at high concentrations to approximately 2/3 near the percolation threshold (f almost-equal-to 0.01). Measureme nts of the magnetoresistance show that the localization length decreas es with dilution.