Chemical and electrochemical synthesis and characterization of polydiphenylamine and poly- N-methylaniline

Abstract

Chemical and electrochemical oxidation of diphenylamine and N-methylaniline in acid produces polyaniline-like polymers, which can be characterized by elemental analysis, cyclic voltammetry, IR, UV-visible and mass spectroscopy. Diphenylamine undergoes para C-C coupling to oligomers ( n = 3-4), while N-methylaniline couples C-N at the para position, attaining a high degree of polymerization. The conductivity of polydiphenylamine (3 × 10 −2 Ω −1 cm −1) increases when polymerization is performed in acetonitrile (0.5 Ω −1 cm −1), in which nincreases to 10–11. Poly- N-methylaniline has a conductivity of 1 × lO −3 Ω −1 cm −1. The polymers are oxidized reversibly from the yellow (leuco) to the green form (emeraldine) and finally to the blue (pernigraniline) form in two steps, each involving 0.5 electrons per monomeric unit. With increasing chain length and conductivity, the electrochemical stability of the emeraldine form of polydiphenylamine also increases.