Microwave-assisted synthesis of functionalized polyaniline nanostructures with advanced antioxidant properties

Abstract

Facile and fast microwave- (MW) assisted synthesis of copolymers of aniline and 2-aminobenzoic acid (2ABA) or 2-aminosulfonic acid (2SULFO) was performed by chemical polymerization of several mole ratios of aniline to functionalized aniline (FA). The physicochemical properties of the copolymers thus prepared were compared with the poly(aniline-co-2-aminobenzoic acid) (2ABAPANI) and poly(aniline-co-2-sulfonic acid) (2SULFOPANI) copolymers synthesized by conventional synthesis (CS) at the same temperature. FTIR and UV-vis spectra show the 2ABAPANI or 2SULFOPANI structure in all samples synthesized either conventionally or in the microwave reactor, however the yield was 2.5-3 times higher for nanostructured functionalized copolymers (fPANI) synthesized by MW. The effect of microwave irradiation on the antioxidant properties of the nanostructured 2ABAPANI and 2SULFOPANI copolymers was investigated. These samples showed 2.1-2.4 times better radical scavenger efficacy than their conventionally synthesized counterparts. A formation mechanism of polyaniline nanofibers under MW conditions is tentatively proposed based on thermal and nonpurely thermal effects on the nucleation modes. © 2010 American Chemical Society.