Linear and nonlinear conductive spectra of various polymers

The author presents an experimental system which enables measurements of linear as well as nonlinear complex conductivities. Using this system, we have measured nonlinear conductive spectra. We proposed a new empirical function to reproduce the observed linear and nonlinear conductive spectra which show the complicated characteristic frequency dependence together with the relaxation phenomenon. On the basis of these results, the typical size of a connected cluster of the effective sites capable of ion hopping was approximately 4-5 nm. This value was obtained without any additional assumptions by using the values of nonlinear conductivities obtained from experiments. We can also discuss the mechanism of the ion transport in relation to structures. Thus, the nonlinear measurements have been extremely useful in determining the mechanism of ion transport in polymers