Time-Humidity-Superposition Principle in Electrical Conductivity Spectra of Ion-Conducting Polymers

We analyze the scaling properties of the ac conductivity spectra of ion-conducting polyelectrolyte complexes of different compositions. Spectra were taken at ambient temperature but at different relative humidities. For the first time, we report on a scaling principle for conductivity spectra termed time-humidity-superposition principle in analogy with the well-known time-temperature-superposition principle. This model-free scaling holds for different materials over several decades in frequency. It implies that the hydration is activating ion motion over short and long distances in a similar general way, a concept so far only established for thermal energy.