Electrets

A process for preparing polymer electrets comprising the following steps:

• (a) providing two electrodes in a deposition zone, said electrodes being in a spaced relationship to one another, having opposing surfaces, and being connected to an external voltage source capable of impressing an intense electric field between the opposing surfaces;
• (b) providing a dipolar p-xylylene monomer vapor in sufficient amount to coat the opposing surfaces of the electrodes;
• (c) activating the power source to provide sufficient potential to align the dipoles of the p-xylene monomer coat;
• and
• (d) introducing the vapor from step (b) into the deposition zone, said zone being under vacuum and at a temperature at which the vapor will condense,
• whereby the vapor condenses on the opposing surfaces of the electrodes, the monomer polymerizing to parylene, coating said surfaces, and forming electrets.