US Patent 7393391 - Nanoporous membrane with hydrophilic and hydrophobic sides

http://www.freepatentsonline.com/7393391.html

This patent from the University of New Mexico teaches forming nanoporous films in which one side of the porous film is provided with a hydrophobic treatment and the other side is provided with a hydrophilic treatment in order to facilitate nanofiltration and nanofluidic transport. Claim 1 reads:

1. A method of forming a nanoporous membrane comprising:

growing a nanoporous oxide film on a substrate;

forming a nanoporous membrane comprising a top side and a bottom side by partially separating the nanoporous oxide film from the substrate;

depositing a fluorocarbon film on the top side of the nanoporous membrane by plasma polymerization.