Soluble and methane sulfonic acid doped poly(diphenylamine) - synthesis and characterization

Diphenylamine (DPA) was polymerized by electrochemical and chemical methods in 3 M methane sulfonic acid (MeSA). Cyclic voltammetry was used for simultaneous synthesis and characterization of poly(diphenylamine), PDPA. In-situ spectroelectrochemical study on polymerization of DPA was made to identify the PDPA formation. The UV-visible spectrum recorded during electropolymerization reveals the existence of poly(p-diphenylene) and polyaniline (PANI) units through absorption bands around 380, 470 and 570 nm. PDPA was found to be doped by MeSA. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) were used to determine the doping level of PDPA by MeSA. The presence of S peak in survey level XPS of PDPA and definite weight loss (13%) equivalent to doping level as noticed through thermogram, of PDPA support the doped nature of PDPA. The MeSA-doped PDPA was found to be soluble in N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methylpyrrolidinone (NMP) and tetrahydrofuran (THF). (C) 2002 Elsevier Science B.V. All rights reserved.