Polyaniline (PANI) nanofibers with a higher conductivity (10-2～10-1 S/cm) were synthesized by “template-free” method in the presence of ferric chloride as oxidant at dopant-free via interfacial polymerization of aniline (An).Compared with previous interfacial polymerization

this method is more simple and cheap because ferric chloride acting as both oxidant and dopant at the same time

resulting in omitting external dopant.Moreover

the resulting nanofibers show thinner diameter and higher crystallinity than those of the nanofibers oxidized by APS which perhaps due to its low redox potential of FeCl3.It is also found that the morphology and conductivity of the nanofibers at room-temperature change with the increase of ［FeCl3］/［An］ ratios.The nanofibers were characterized by FTIR and UV-Visible absorption spectra

and the results indicated that they were identical to the emeraldine salt state of PANI.