Method of making electret articles based on zeta potential

Abstract

A method of making an electret article, from a polymeric article that has a zeta potential of greater than or less than −7.5 millivolts. The article is charged by contacting it with an aqueous liquid that has a pH and conductivity as follows: (i) if the article has a zeta potential of −7.5 mV or less, then the contacting liquid has pH greater than 7 and a conductivity of 5 to 9,000 microSiemens per centimeter; and (ii) if the article has a zeta potential of greater than −7.5 mV, then the contacting liquid has a pH of 7 or less and a conductivity of 5 to 5,500 microSiemens per centimeter. An electret article made in this manner can provide improved electret performance, particularly in electret filtration articles.

Dependencies are inferred from the claim text.