Preparation of tetra star-shaped conducting polymers based on polyaniline , and blend with polycaprolactones for preparation of nanofibers via electrospinning method

Among the known organic conducting polymers, polyaniline (PANI) has attracted special attention. Several methods have been developed to improve the processibility of PANI[1-2]. In this work, we used PEG because of its good properties such as hydrophilicity and biodegradability to synthesis of A2BA2 tetraarm star-shaped polymer with A= PANI and B= PEG. In the first step, PEG (Mn~2000 g/mol) was capped by an epoxy group at the ω-position by the reaction with epichlorohydrin. Then, the epoxy ring was converted into two hydroxyl groups by hydrolysis. At the next step, these hydroxyl groups were esterified with 4-amino benzoic acid. Finally, the star polymer was prepared by reaction of this end functionalized PEG with ammonium persulfate as initiator for polymerization of aniline monomers. In this step, both polyaniline homopolymer and star polymer were formed. We seprated them upon their solubility. Thene the blends of copolymers and polycaprolactone prepared by electrospinning method and are converted into the fibrs.. The chemical structure of star polymer was determined by FT-IR and 1H NMR spectroscopy. Cyclic voltammetry (CV) stedies showed that this star polymer is electroactive. Morphology star polymer and fibers was investigated by scanning electron microscopy (SEM). This novel system opens up new and interesting opportunities for applications such as electroactive scaffold for tissue engineering.