Synthesis, Electrical, Electronic and Charge Transport Properties of Poly(aniline‐co‐p‐toluidine)

Copolymers of aniline with p‐toluidine were synthesized for different molar ratios of the respective monomers in acid medium. The electrical conductivity, charge transport and spectral characteristics upon incorporation of p‐toluidine units into the polyaniline backbone were investigated. The electrical conductivity of the copolymers showed frequency dependence which became more prominent with an increase in the number of p‐toluidine units in the polyaniline backbone. A direct relationship between the frequency dependence and electron localization was observed in the copolymers. Electronic spectra showed blue shifts in the π→π*and benzenoid→quinoid transitions revealing a decrease in the extent of conjugation in the copolymers. The protonated forms of the copolymers were soluble in DMSO giving polaron band around 400 nm. The decrease in electrical conductivity was attributed to the greater electron localizations as revealed from the broader ESR signals. Temperature dependence of electrical conductivity showed that charge transport was mainly through variable range hopping though a mixed conduction behavior was observed at higher temperature range.

Keywords:

• polyaniline
• p‐toluidine
• co‐polymer
• electrical conductivity
• electron localization

5 Acknowledgments

The authors would like to thank the Heads of the Departments of Chemistry and Applied Chemistry, AMU, Aligarh for providing the necessary facilities for the successful completion of this work. The help rendered by Prof. R.J. Singh, Dept. of Physics, AMU, Aligarh for carrying out the ESR experiments is greatly acknowledged.