Electrical transport in conductive blends of polyaniline in poly(methyl methacrylate)

• Published in: Synthetic metals 1994-03, Vol.63 (1), p.47-52
• Main Authors: Yoon, C.O., Reghu, M., Moses, D., Heeger, A.J., Cao, Y.
• Format: Article
• Language: English
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/0379-6779(94)90247-X

The electrical transport properties of solution-processed conducting polyblends of polyaniline-camphor sulfonic acid (PANI-CSA) in poly(methyl methacrylate) (PMMA) are investigated for PANI-CSA over the full range of volume fractions (f) above the percolation threshold. The positive 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 transport properties of PANI-CSA in the blends remain nearly unchanged by dilution. The low temperature resistivity indicates transport by generalized variable range hopping, ϱ(T) = ϱ 0 exp[( T 0 T ) γ] . A systematic change in γ is observed as a function of dilution; γ increases from approximately 1 3 at high concentrations to approximately 2 3 near the percolation threshold ( f ≈ 0.01). Measurements of the magnetoresistance show that the localization length decreases with dilution.