Magnetic susceptibility of polyaniline and polyaniline-polymethylmethacrylate blends

While heat-capacity measurements on polyaniline yield density of states at the Fermi level ${N(E}_F)$ of the order of 3 states/(eV-2 rings), a value of 16 states/(eV-2 rings) was reportedly found from magnetic susceptibility measurements. We report here our magnetic susceptibility measurements, which, in agreement with the heat-capacity results, yield ${N(E}_F)$ of the order of 2 states/(eV-2 rings). These results firmly establish the metallic nature of charge carriers in the polyaniline family.