Redox properties of poly(N-methylaniline)

Smooth. adherent films of poly(N-methylaniline) (PNMA) can be synthesised electrochemically in aqueous solutions containing 1 M H2SO4. The galvanostatic synthesis used in the present study gives a conductivity of 10(-1) S cm(-1) which is the highest value reported so far for PNMA. The redox properties are studied in a wide pH range (H-0 -2.4 for pH 7) using cyclic voltammetry and in situ absorption spectral measurements. A few parallel experiments on polyaniline (PANI) have been carried out for ease of comparison. The results indicate that the deprotonation of PNMA occurs below pH 1. The relative loss of redox activity with respect to increasing pH and the oxidative deterioration are less for PNMA compared to PANI. This will be an advantage in the construction of Zn-PNMA rechargeable cells. PNMA can be synthesised from non-aqueous solvents and its electrochemical stability is less compared to that of the film prepared in aqueous solutions. (C) 2003 Elsevier Science B.V. All rights reserved.