Permeable polyaniline articles for gas separation
AssigneeThe Regents of the University of California
InventorsHsing-Lin Wang, Benjamin R. Mattes
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Abstract
Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 μm thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.
Claims13
A method for preparing a gas-selective, permeable integrally skinned asymmetric membrane (ISAM) which comprises the steps of:
- (a) forming a solution including the emeraldine base form of polyaniline having between 15% and 30% by weight of polyaniline;
- (b) pouring the solution onto a substrate forming thereby a membrane;
- and,
- (c) immersing the membrane in a nonsolvent for polyaniline;
- thereby causing the emeraldine base form of polyaniline to precipitate forming an ISAM having a permeable dense skin in the vicinity of the surface of contact of the membrane with the nonsolvent and a lower density porous support portion wherein a gel inhibitor is added to the solution of the emeraldine base form of polyaniline before said step of pouring the solution.
A method for preparing a gas-selective, permeable integrally skinned asymmetric membrane (ISAM) which comprises the steps of:
- (a) forming a solution of the emeraldine base form of polyaniline having between 15% and 30% by weight of polyaniline;
- (b) pouring the solution onto a substrate forming thereby a membrane;
- (c) immersing the membrane in a nonsolvent for polyaniline, thereby causing the emeraldine base form of polyaniline to precipitate forming an ISAM having a permeable dense skin in the vicinity of the surface of contact of the membrane with the nonsolvent, and a lower density porous support portion;
- and, caulking the dense skin after said step of immersing the membrane in a nonsolvent for polyaniline.
A method for preparing a gas-selective, permeable integrally skinned asymmetric membrane (ISAM) which comprises the steps of:
- (a) forming a solution including the emeraldine base form of polyaniline having between 15% and 30% by weight of polyaniline and a polymer other than polyaniline;
- (b) pouring the solution onto a substrate forming thereby a membrane;
- and, (c) immersing the membrane in a nonsolvent for polyaniline, thereby causing the emeraldine base form of polyaniline to precipitate forming a blended polymer ISAM having a permeable dense skin in the vicinity of the surface of contact of the membrane with the nonsolvent, and a lower density porous support portion.
Dependencies are inferred from the claim text.