Influence of the gas media on the stability of corona charged polyethylenterephtalate films stored at low pressure

PET corona electrets charged in different gas media and stored at low pressures were investigated. At low pressures the charge particles desorption from electrets surface is most likely to occur. Hence the surface potential has the lowest value for all gas media. Due to the release of charges from surface traps during the storage at low pressure termostimulated discharge curves of the samples which were preliminary stored at low pressure are shifted slightly to higher temperature. At an elevated temperature the bulk will play determinant role and the gas media in which the samples have been charged does not substantially influences the curve runs.