Synthesis of conductive polyaniline-modified polymers via a combination of nitroxide-mediated polymerization and "click chemistry"

Abstract

A new strategy for graft copolymerization of aniline onto polystyrene by a multi step process is suggested. For this purpose, firstly poly(styrene-co-4-chloromethyl styrene) [P(St-co-CMSt)] was synthesized via nitroxide-mediated polymerization (NMP) and then the chlorine groups of copolymer were converted to azide groups by a substitution nucleophilic reaction in the presence of a solvent composed of sodium azide (NaN3), and dry N,N-dimethylformamide (DMF). Afterwards, "click" cycloaddition reaction was employed for the introduction of phenylamine groups into the polystyrenic backbone by reaction between the azido copolymer and 4-aminobenzonitrile in the presence of anhydrous ZnCl2 as the catalyst. The graft copolymerization of aniline monomers onto phenylamine-functionalized polystyrene was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped polyaniline was chemically grafted onto the polystyrenic backbone via oxidation polymerization. The obtained graft copolymer was characterized by H-1 nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy, and its electroactivity behavior was verified under cyclic voltammetric conditions. Moreover, the thermal behaviors of the obtained polymers were examined by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA).