Polyaniline nanofibers: towards pure electrospun PANI

Nanofibers of conducting polymers, as polyaniline (PANI), have received a great deal of attention by the scientific community for their potential applications (electronic, magnetic, biomedical, optical fields). Recently the electrospinning has emerged as a promising technique to produce wires and fibers of polymers with diameters ranging from 10 nm to 10 m. PANI has poor processability by electrospinning due to its poor solubility in common solvents, but it is possible to spun polyaniline nanofibers adding another polymer to the organic solutions. The presence of an insulator copolymer decreases the fibers/wires conductivity. In this work we report the preparation of highly pure polyaniline fibers by electrospinning process. PANI powder has been characterized by FT-IR, UV-VIS, and X-Ray diffraction. The spun sample obtained have been characterized by SEM to evaluate the wire morphology and complex impedance spectroscopy (EIS) in order to measure the electrical conductivity. We observed that, reducing the amount of PEO in the PANI/PEO blend organic solution, the fiber sizes decreased from 421nm for higher content of PEO (PANI: PEO= 1: 1, w/w) to 230 nm (PANI: PEO= 1: 0.1, w/w). The way to collect the fiber has been also investigated. Using a rotanting collector we observed a stretching effect on the fibers which promotes a narrow distribution of fibers dimension with respect to the fibers obtained with static collector.