Some Effects of Vapors on Electret Behavior

The effects of various vapors on the growth and decay of electret polarization have been studied. Particular emphasis was given to the effect of water vapor on polyvinyl acetate. The observed effects appear to arise from two causes: (1) a decrease in the relaxation time and an increase in the magnitude of the volume polarization following infusion of vapor into the dielectric; (2) an increase in the transfer of charge by means of interfacial discharge at the dielectric-electrode gap. The infusion of a polar vapor into a nonpolar solid dielectric gave anomalously large values of volume polarization. The dielectrics studied were polyvinyl acetate, polyethylene, two acrylic resins, and carnauba wax. The vapors used successfully were water and chlorobenzene; unsuccessful attempts were made to use benzene and isopropyl ether.