Hb-induced biocatalyzed synthesis of water-soluble polyaniline nanocomposites with controlled handedness in DBSA–CTAB mixed micelle solutions

Abstract A new polymerization system for the synthesis of chiral conducting polyaniline (PANI) with high conductivity catalyzed by hemoglobin (Hb) in dodecylbenzenesulfonic acid (DBSA)–cetyltrimethyl ammonium bromide (CTAB) mixed micelle solutions was developed. For the first time, without any other chiral inducer, PANI with controlled handedness was found to be acquired only in the presence of Hb, indicating that Hb played the role of both the inducer and biocatalyst. The effects of reaction pH, concentrations and ratio of the mixed surfactants on the formation of chiral PANI were explored. Results revealed that the conductivity of chiral PANI was closely associated with the molar ratio of DBSA to CTAB. When the ratio of DBSA to CTAB was 3:1, the highest conductivity of 39.71 S/cm was obtained. The chiral PANI was characterized by UV–vis absorption spectroscopy, circular dichroism (CD) spectra, Fourier transform infrared spectra (FTIR), field emitted scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Our results demonstrated that this novel system was specific, simple and green, in which the controlled handedness PANI was obtained with various morphologies and high conductivity.