Conditions of polymerization and doping have great influence upon the grain shape and electrical performance of doped polyaniline (PA). In this paper, doped PA was obtained by chemical oxidation in-situ polymerization process in high magnetic field (HMF) and the grain structure and shape were studied by TEM and electrical performance of doped polyaniline composite. The results indicated that the grain shape of in-situ polymerized PA in HMF of 0 T was irregular reef-like, and that in HMF of 10 T was open-ramified rod-like with diameter of 50 nm, but the volume resistivity of the composite was about 3 order greater than that of the doped PA composite at 0 T. The grain shape of secondary doped PA at 10 T was changed to spherical structure about 20～30 nm in diameter, and the volume resistivity of its composite was about 1 order less than that of the doped PA composite at 0 T. It was thought that the reason for different grain shape and the electrical conductivity was anisotropic diamagnetic susceptibility of doped PA and orientations and the influence of the HMF on the polymerization and doping.

Key words: polyaniline, high magnetic field, grain shape, orientation, volume resistivity