Polyaniline (PANI) base was doped with camphorsulfonic acid (CSA) in the solid state by high-energy ball milling. The morphology and structure of the as-made PANI-CSA salt were characterized by SEM, XRD and FT-IR spectroscopy, and the conductivity of the PANI-CSA was measured by a four-probe method. The protonation of polyaniline base is reflected by the changes in the infrared spectra. Evidenced by the XRD spectra, alignment of the polyaniline chain was induced by the ball milling, which is beneficial for electric charge transfer. The effect of the milling time on the conductivity and the doping level was also investigated. The results showed that the solid-state doping occurred with a fast rate, and both the conductivity and the doping level increased in the early stage of ball milling, and then dropped down. A maximum of conductivity of 3.25 S/cm was reached, corresponding to a doping level of 0.31.

Key words: polyaniline, solid-state doping, high-energy ball-milling, electrical conductivity