A novel method for electret production using impulse voltages

A novel method for producing electrets is proposed in which an electric discharge is induced by a negative impulse voltage in a small air gap. The dielectric foil to be charged is placed between two planar electrodes, being in contact with one of them and separated from the other by the air gap. The electric discharge in the gap causes electric charges to deposit onto the dielectric surface where they are trapped, thus forming the electret. Measurements carried out with Teflon FEP (fluoroethylene propylene) show a very uniform deposition, and that the sample surface potential increases linearly with increasing impulse peak voltage. In principle, this method compares with the corona discharge for the production of electrets with regard to high turnout and low cost.< >