Current-voltage characteristic and relation between surface charge density of PMMA thermoelectrets and polarizing voltage

Current-voltage characteristic j-V of PMMA at T<Tg is in sub-ohmic shape (j=gVⁿ where n <1). Using the above data, a two layers condensor (PMMA one-sided metallized and air-gap) has been considered as the formation model of PMMA thermoelectrets. It follows from this model that the inter-facial charge density changes non-linearly with the applied voltage. The analysis data are compared with the experimental results of PMMA thermoelectrets.