3,5-Dinitrosalicylic acid-assisted synthesis of self-assembled polyaniline nanorods

Abstract

Self-assembled polyaniline nanorods were synthesized by the oxidation of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 3,5-dinitrosalicylic acid, using the template-free falling-pH method. The effects of the mole ratio of 3,5-dinitrosalicylic acid to aniline, i.e., of starting pH, monomer concentration, and reaction time on the yield of polymerization, molecular-weight distribution, molecular structure, morphology, and conductivity of the prepared polyanilines have been studied by gelpermeation chromatography. elemental analysis, FTIR and Raman spectroscopies, scanning and transmission electron microscopies, and conductivity measurements. The weight-average molecular weights and polydispersity index were in the range 36,400-54,900 and 3.7-7.6, respectively. Synthesized polyaniline nanorods have a diameter of 25-280 nm and a length of 0.2-1.31 mu m, and conductivities in the range (1.2-4.6) x 10(-2) S cm(-1). The formation mechanism of self-assembled polyaniline nanorods has been discussed.