Crystal Structure and Property of Proton Acid and Polypeptide Co-doped Polyaniline

An approach was presented in this article for organizing the polyaniline (PANI) nanoparticles using polypeptide as the template. PANIs were chemically synthesized in different weight ratios of poly(d-Glu-d-Lys) (PDGDL)/aniline (Ani) (mg/g) in the feed, doped acid, and polymerization time. Scanning electron microscopy and X-ray diffraction analysis showed that the PDGDL dictated the organization of the PANI nanoparticles. The formation and shape of PANI crystal structures were strongly affected by the parameters including weight ratio of PDGDL/Ani, doped acid, and polymerization time. Fourier transform infrared and UV–vis near-infrared spectrometry confirmed the strong interaction between PDGDLs and PANIs. Semiconductor parameter analyzer test showed that the conductivity of proton acid and polypeptide co-doped PANIs increased with the increase of the weight ratio of PDGDL/Ani and increased with the polymerization time extended from 12 to 60 h, but decreased from 60 to 72 h. Solubility test indicated that the solubility of these PANIs was also strongly affected by the parameters as mentioned above. My investigation suggested that there was an optimum weight ratio and polymerization time to obtain certain regular structure and properties of the proton acid and PDGDL co-doped PANIs.