Charge storage in nonmetallized PFA film

Abstract Nonmetallized electrets are advantageous for applications in electret electro-acoustical transducers based on the three layer condenser. We have modified the breakdown method [1] and charging using a nonwetting liquid [2] to produce nonmetallized PFA electrets by application of additional dielectric inserts. The surface density of electrets thus produced is discussed as dependent on the thickness and dielectric properties of the insert. Very stable/in2 time and temperature/PFA electrets of the charge density order of 10−5 C/m2 are obtained using these methods. The effective charge stored was found to be located near the middle of the foil after the ageing procedure. Moreover, the way of surface charge density estimation of nonmetallized electrets is proposed.