Synthesis and Characterization of "Hairy Urchin"-like Polyaniline by Using β-Cyclodextrin as a Template

A novel synthesis of "hairy urchin"-shaped polyaniline (PAni) and its surface coverage with nanospikes was achieved from a simple microemulsion polymerization technique in the presence of beta-cyclodextrin (beta-CD). The rodlike micelle phase was characterized, and the key factors affecting the formation of PAni nanostructures were systematically examined. Ferric chloride (FeCl3) has played a role as a structural directing agent to fabricate the polymer as hairy urchin-like structure/nanorods via a cooperative interaction between FeCl3 and DoTAC in an aqueous medium. Host guest inclusion complex of beta-cyclodextrin with aniline was used as a monomer. It has been revealed that the formation of the supramolecular complexes of polyaniline with beta-CD due to host guest interaction is indispensable for the fabrication of these unique PAni nanostructures, and a suitable beta-CD to aniline molar ratio is essential to their exclusive formation. Different varieties of PAni nanostructures such as hairy urchin, branched particles consisting of rodlike branches, and regular rodlike particles were obtained in the presence of FeCl3. Also, in the absence of FeCl3, a predominant product of regular spherical particles and wirelike aggregation exhibiting faceted surfaces were obtained. The structures of polyaniline hairy urchin-like nanorods were analyzed using transmission electron microscopy (TEM). The synthesized polymer was characterized by Fourier-transform infrared spectroscopy and X-ray diffraction technique. Additionally, the relationship between the morphology and the conductivity of the PAni nanostructures was investigated as well.