US Patent 7309385 - 3D nanostructure gas separation membrane

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Gas separation membranes must balance both the selectivity in the gases that are passed and the permeability of the membrane and an improvement in one of selectivity or permeability comes at the cost of the other. This invention provides a high surface area membrane structure using nanostuctured tubes to enhance the permeability without sacrificing selectivity. Claim 1 reads:

1. A gas separation membrane of two or more layers comprising a separating layer of 3-dimensional nanostructure and a supporting layer, wherein the 3-dimensional nanostructure contains the array of hollow tubes whose heads are closed and bottoms are open.