LINEAR AND NONLINEAR CONDUCTIVE SPECTRA OF POLYETHYLENE OXIDE SALT COMPLEX/

A new experimental system has been developed, which enables measuremen ts of linear as well as non-linear complex conductivities to be made. The frequency dependence of linear to fifth-order non-linear complex c onductivities at different temperatures in a polyethylene oxide/salt c omplex can then be measured. A characteristic conduction relaxation ph enomenon was observed in the spectra, which suggested the existence of different ion-conduction mechanisms between the high- and low-frequen cy regions. It was also found that the ratio of linear to non-linear c onductivities was closely related to the elementary process of ionic t ransport. Furthermore, this ratio obtained from non-linear measurement s allowed an estimate of the important parameters which characterized ionic transport in ion-conducting polymers, such as the hopping distan ce of an ion or the size of a connected cluster of the site capable of ion hopping, without the need for any additional assumptions. Thus, i t was found that in a polyethylene oxide/salt complex, the typical siz e of a connected cluster of the effective sites capable of ion hopping was approximately 4 nm.