The spectroscopic impedance of cellophane

Abstract

The electrical impedance of cellophane has been measured as a function of moisture content and temperature in the frequency range 10⁻³ – 10⁵ Hz. The data show a very strong dependence on moisture content, which is a typical characteristic of hygroscopic solids, and at low frequencies, remarkable constant phase angle spectra were obtained. Making use of the hopping model of conduction in non-crystalline solids, we explain the measured spectra. The model treats absorbed water as an impurity in the cellophane and conduction is predicted to occur by temperature-activated proton hopping between water molecules. We also propose that this model is widely applicable to prediction of the low frequency dielectric properties of hygroscopic solids.