This invention relates to a method of making a fluid separation material such as membrane of nanopore structure. An object of this invention is to provide a method of making a fluid separation material such as membrane which has wide permeability and selectivity range and is simple and easy to carry out. Prof. J. Bellare of Department of Chemical Engineering and his colleagues from Department of Chemistry have developed a novel method for making a fluid separation material and came up with a membrane of nanopore structure comprising a conducting porous polymer film to obtain a porosity of 0.01 to 50% in the nanopore sizes of 0.05 to 17 nanometers.

The inventors provided several embodiments of this new method. One of the methods comprises chemically synthesizing a free standing conducting polymer membrane of 50 to 10000 microns thickness and nanoengineering the pore structure to obtain a porosity of 0.01 to 50% and pores in the nanosizes of 0.05 to 17 nanometers. Another method comprises casting a conducting polymer membrane of 0.01 to 100 microns thickness on a porous substrate of 10 to 70% porosity with the respective polymer solution and nanoengineering the pore structure.

The porous substrate may be of inherent conductivity made from conducting material or of induced conductivity made from a non-conducting material or ceramics and coated with a conducting material.

The permeability of the membrane obtained by the method of the invention has been found to be 25.3 to 0.000005 and the selectivity has been found to be 100-59000. The method of the invention is simple and easy to carryout and can be used for the separation of liquids or gases.