US Patent 7438193 - Coated nanoporous membrane

http://www.freepatentsonline.com/7438193.html

This patent from Postech Foundation (Korea) teaches the formation of a filtration membrane having a high density of nanopores in which an inner portion and a surface portion are formed of different polymers. Claim 1 reads:

1. A nanoporous membrane comprising:

a support; and

a separation layer including a plurality of nano-sized pores at a density of 10^10/cm2 or greater and a matrix wherein said matrix of said separation layer includes an inner portion and a surface portion covering said inner portion.