Spectroelectrochemical Investigations of Soluble Polyaniline Synthesized via New Inverse Emulsion Pathway

A new inverse emulsion protocol has been developed for the synthesis of polyaniline (PANI), which can be dissolved completely in common organic solvents such as chloroform. Benzoyl peroxide is used as the oxidizing agent and toluene + 2-propanol−water is used as the solvent. Dodecylbenzenesulfonic acid (DBSA) has been selected as the dopant because it also functions as the surfactant. Cyclic voltammetry and spectroelectrochemical investigations were carried out to study the electroactivity, UV−Vis response, and metal-to-insulator transition of the chemically synthesized PANI as a function of applied electrode potential. At more positive potentials, cyclic voltammograms of PANI in aqueous acids show two oxidation waves caused by redox processes of PANI as observed with electrochemically prepared PANI. Peak position and shape are influenced by the slow anion exchange rate. Electrical conductivity of the material is relatively high as the minimum resistance value is nearly 10 Ω. SEM investigations show that the amount of DBSA in the feed strongly influences the morphology of the polymer. In situ UV−Vis spectroscopy measurements reveal good electrochromic reversibility for the polymer very similar to the response of PANI synthesized electrochemically.