A novel method for electret production using impulse voltages

A method for producing electrets is proposed in which an electric discharge is produced by a negative impulse voltage in a small air gap. The dielectric film to be charged is placed between two planar electrodes, the film being in contact with one of the electrodes 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 show a very uniform deposition, and also that the sample surface potential increases linearly with increasing impulse peak voltage. This method appears to be as good as the corona discharge for the production of electrets, with regards to a high turn out and low cost