US Patent 7691168 - Charged nanofiber filter

http://www.freepatentsonline.com/7691168.html

This patent from 3M teaches using polymer nanofibers to form a more efficient air filter. Claim 1 reads:

1. Charged multilayer media that comprises:

a) a hydrocharged fibrous filtration layer that contains a plurality of intertwined nanofibers that have a length of about 12 to about 300 mm, and

b) a porous roll-to-roll processable support layer.