# US 2014/0154499 A1 · Method and Membrane for Nanoporous, Bicontinuous Cubic Lyotropic Liquid Crystal Polymer Membranes that Enable Facile Film Processing and Pore Size Control

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- Number: US 2014/0154499 A1
- Document ID: US20140154499A1
- Status: Published application
- Kind: A1
- Application number: 14/234,362
- Filed: 2012-07-22
- Published: 2014-06-05
- Earliest claimed: 2011-07-22
- Assignees: The Regents of the University of Colorado, a body corporate
- Inventors: Douglas L. Gin; Blaine M. Carter; Brian R. Wiesenauer; Evan S. Hatakeyama; Richard D. Noble; John L. Barton
- Web page: https://patentgrep.com/patent/US20140154499A1

## CPC

- C08J 5/00: Manufacture of articles or shaped materials containing macromolecular substances (manufacture of semi-permeable membranes B01D67/00 - B01D71/00)
- B01D 67/00: Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D 69/10: Supported membranes; Membrane supports
- B01D 71/06: Organic material
- B01D 71/58: Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
- B01D 71/82: characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
- C08F 26/06: by a heterocyclic ring containing nitrogen
- C09K 19/02: characterised by optical, electrical or physical properties of the components, in general
- C09K 2019/525: {Solvents}
- C09K 2019/528: {Surfactants}
- C09K 2219/03: in the form of films, e.g. films after polymerisation of LC precursor
- Y10T 428/249981: Plural void-containing components
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of forming a nanoporous membrane includes preparing a solution of a gemini Imidazolium Lyotropic Liquid Crystal (LLC) monomer, a polar low-volatility organic solvent, and a radical photo-initiator in a volatile organic solvent; solvent-casting the solution onto a porous material, evaporating the volatile organic solvent; heating such that the gemini imidazolium monomer forms a Q-phase material and photopolymerizing the imidazolium monomer by exposing the radical photo-initiator to UV light; and exchanging the polar low-volatility organic solvent. Also disclosed is a membrane composed of polymerized gemini imidazolium LLC monomers, and a thin-film composite membrane having the Q-phase material supported on a porous supporting membrane.

## Claims

### Claim 1

A method of forming a nanoporous membrane comprising:
preparing a solution of a gemini imidazolium lyotropic liquid crystal monomer, a polar low-volatility organic solvent, and a radical photo-initiator in a volatile organic solvent;
solvent-casting the solution onto a porous material;
evaporating the volatile organic solvent;
heating to a temperature such that the gemini imidazolium monomer forms a Q-phase material;
photopolymerizing the imidazolium monomer by exposing the radical photo-initiator to light; and
removing the polar low-volatility organic solvent.

### Claim 2 (depends on 1)

The method of claim 1 wherein the gemini imidazolium lyotropic liquid crystal monomer is selected from the group consisting of 1,4-Bis(tetradeca-11,13-dienylimidazolium)butane dihalide (monomer 3a), 1,6-Bis(tetradeca-11,13-dienylimidazolium)hexane dihalide (monomer 3b), 1,1′-(oxydi-2,1-ethanediyl)bis[3-(tetraadeca-11,13-dienyl)imidazolium] dihalide (monomer 3c), 1,4-Bis(octadeca-15,17-dienylimidazolium)butane dihalide (monomer 3d), 1,6-bis(octadeca-15,17-dienylimidazolium)hexane dihalide (monomer 3e), and 1,1′-(Oxydi-2,1-ethanediyl)bis[3-(octadeca-15,17-dienyl)imidazolium] dihalide (monomer 3f).

### Claim 3 (depends on 2)

The method of claim 2 wherein the gemini imidazolium lyotropic liquid crystal monomer is monomer 3e.

### Claim 4 (depends on 3)

The method of claim 3 wherein halide of the gemini imidazolium lyotropic liquid crystal monomer is bromide.

### Claim 5 (depends on 1)

The method of claim 1 wherein the solution further comprises a single-head/single-tail LLC monomer.

### Claim 6 (depends on 5)

The method of claim 5 wherein the Gemini imidazolium lyotropic liquid crystal monomer is selected from the group consisting of 1,4-bis(tetradeca-11,13-dienylimidazolium)butane dihalide (monomer 3a), 1,6-bis(tetradeca-11,13-dienylimidazolium)hexane dihalide (monomer 3b), 1,1′-(oxydi-2,1-ethanediyl)bis[3-(tetraadeca-11,13-dienyl)imidazolium] dihalide (monomer 3c), 1,4-bis(octadeca-15,17-dienylimidazolium)butane dihalide (monomer 3d), 1,6-bis(octadeca-15,17-dienylimidazolium)hexane dihalide (monomer 3e), and 1,1′-(Oxydi-2,1-ethanediyl)bis[3-(octadeca-15,17-dienyl)imidazolium] dihalide (monomer 3f).

### Claim 7 (depends on 6)

The method of claim 6 wherein the single-head/single-tail monomer is 3-methyl-1-(octadeca-15,17-dienyl)imidazolium dibromide (monomer 4).

### Claim 8 (depends on 7)

The method of claim 7 wherein the gemini imidazolium lyotropic liquid crystal monomer is monomer 3e.

### Claim 9 (depends on 1)

The method of claim 1 wherein the gemini imidazolium lyotropic liquid crystal monomer has a linking alkyl group of length from four to thirty.

### Claim 10 (depends on 1)

The method of claim 1 wherein the gemini imidazolium lyotropic liquid crystal monomer has a double-diene-terminated aliphatic chain of total length between fourteen and thirty.

### Claim 11 (depends on 10)

The method of claim 10 wherein the gemini imidazolium lyotropic liquid crystal monomer has a linking alkyl group of length from four to thirty.

### Claim 12 (depends on 11)

The method of claim 11 wherein the Gemini imidazolium lyotropic liquid crystal monomer is monomer 3e.

### Claim 13

A nanoporous membrane comprising a polymer of at least one gemini imidazolium lyotropic liquid crystal monomer selected from the group consisting of a salt of 1,4-Bis(tetradeca-11,13-dienylimidazole)butane (monomer 3a), 1,6-Bis(tetradeca-11,13-dienylimidazole)hexane (monomer 3b), 1,1′-(oxydi-2,1-ethanediyl)bis[3-(tetraadeca-11,13-dienyl)imidazole] (monomer 3c), 1,4-Bis(octadeca-15,17-dienylimidazole)butane (monomer 3d), 1,6-bis(octadeca-15,17-dienylimidazole)hexane (monomer 3e), and 1,1′-(Oxydi-2,1-ethanediyl)bis[3-(octadeca-15,17-ienyl)imidazole] (monomer 3f); the membrane being nanoporous with QI-phase structure.

### Claim 14 (depends on 13)

The membrane of claim 13 wherein the gemini imidazole lyotropic liquid crystal monomer is monomer 3e.

### Claim 15 (depends on 14)

The membrane of claim 14 wherein the polymer further incorporates a single-head/single-tail LLC monomer.

### Claim 16 (depends on 13)

The membrane of claim 13 wherein the polymer further incorporates a single-head/single-tail LLC monomer.

### Claim 17 (depends on 16)

The membrane of claim 16 wherein the single-head/single-tail monomer is 3-Methyl-1-(octadeca-15,17-dienyl)imidazolium dibromide (monomer 4).

### Claim 18 (depends on 13)

The membrane of claim 13 wherein the gemini imidazolium lyotropic liquid crystal monomer is monomer 3e.

### Claim 19 (depends on 13)

A thin-film composite membrane comprising the nanoporous membrane of claim 13 disposed upon a porous supporting membrane.

### Claim 20 (depends on 19)

The membrane of claim 19 wherein the gemini imidazolium lyotropic liquid crystal monomer is monomer 3e.

### Claim 21 (depends on 20)

The membrane of claim 20 wherein the polymer further incorporates a single-head/single-tail LLC monomer.

### Claim 22 (depends on 21)

The membrane of claim 21 wherein the single-head/single-tail monomer is 3-Methyl-1-(octadeca-15,17-dienyl)imidazolium dibromide (monomer 4).

### Claim 23 (depends on 13)

The membrane of claim 13 wherein the salt is a imidazolium salt comprising a halide selected from the group consisting of fluoride, bromide, chloride, and iodide.

### Claim 24

A nanoporous membrane designated C comprising a polymer formed from at least one gemini lyotropic liquid crystal (LLC) monomer salt, each twin of the gemini LLC comprising a pyridinium group, a double-diene tail of total length 14 to 30, and a anion comprising a halide, nitrate, acetate, or sulfate, the gemini LLC having a linking group of length from 4 to 30, the membrane having QI phase structure.