Nonlinear ionic-conductivity spectra of antistatic polymer films

We measured the frequency dependence of linear to third-order nonlinear complex conductivities and permittivities of a new antistatic polymer film (NASPF), that is, a composite film which consists of highly conductive butadiene rubber (BUT) particles containing Li+ and poly(methyl methacrylate), at room temperature. The nonlinear conductivities obtained allowed an estimate of the important parameters which characterize ionic transport in the composite film, such as the hopping distance of ions or the size of a cluster connected to the site capable of ion hopping, without any additional assumptions. We obtained two hopping distances, 68 and 380 nm. The former may correspond to the distance between adjacent hopping sites in one BUT particle. The latter corresponds to the average size of the clusters formed by some BUT particles, in which ions can move freely. The results are consistent with transmission electron microscopic image data concerning BUT particle dispersion in the NASPF.