Asymmetric nanotube containing membranes
AssigneeNanOasis
InventorsTimothy V. Ratto, Jason K. Holt, Alan W. Szmodis
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Abstract
This invention relates to heterogenous pore polymer nanotube membranes useful in filtration, such as reverse osmosis desalination, nanofiltration, ultrafiltration and gas separation.
Claims19
A process for the fabrication of a membrane of selective permeability, said process comprises:
- (a) coating a substrate with a film of polymer solution comprising a polymer dissolved in a solvent;
- (b) forming over said film of polymer solution a nanotube dispersion layer comprising nanotubes dispersed in a liquid carrier that is partially miscible with, but forms a separate liquid phase from, said polymer solution;
- (c) evaporating said liquid carrier from said nanotube dispersion layer to leave a residual nanotube dispersion in said polymer solution and nanotubes protruding from said nanotube dispersion;
- and
- (d) contacting said residual nanotube dispersion layer with a liquid that is at least partially miscible with said solvent but in which said polymer is substantially insoluble, to cause precipitation of said polymer to form an asymmetric membrane terminating on one side in a skin that forms a substantially impermeable barrier around said nanotubes with said nanotubes protruding through said skin.
A membrane of selective permeability, said membrane comprising an asymmetric porous polymer and terminating on one side in a skin, with open-ended nanotubes embedded in said skin, said nanotubes having substantially random orientations relative to said skin and at least a portion of the nanotubes each having two open ends protruding through opposite surfaces respectively of said skin to provide fluid communication through each of said nanotubes through said membrane, and said skin foiming a substantially impermeable barrier around said nanotubes.
Dependencies are inferred from the claim text.