Nanostructured polyelectrolytes for ion-selective membranes

Patent metadata

Field	Value
Publication number	US-10766005-B2
Application number	US-201816128081-A
Country	US
Kind code	B2
Filing date	Sep 11, 2018
Priority date	Sep 11, 2018
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Nanostructured polyelectrolyte bilayers deposited by Layer-by-Layer deposition on nanoporous membranes can be selectively crosslinked to modify the polyelectrolyte charge density and control ionic selectivity independent of ionic conductivity. For example, the polyelectrolyte bilayer can comprise a cationic polymer layer, such as poly(ethyleneimine), and an anionic polymer layer, such as poly(acrylic acid). Increasing the number of bilayers increases the cation selectivity when the poly(ethyleneimine) layer is crosslinked with glutaraldehyde. Crosslinking the membranes also increases the chemical and mechanical strength of the polyelectrolyte films. This controllable and inexpensive method can be used to create ion-selective and mechanically robust membranes on porous supports for a wide range of applications.

First claim

We claim:

1. A method to fabricate an ion-selective membrane, comprising the steps of:
providing a nanoporous membrane; and
layer-by-layer depositing at least one polyelectrolyte bilayer on at least one side of the nanoporous membrane, wherein the polyelectrolyte bilayer comprises a cationic polymer layer and an anionic polymer layer; and either
chemically crosslinking or charge-neutralizing the cationic polymer, thereby decreasing a cationic fixed charge in the polyelectrolyte bilayer; or
chemically crosslinking or charge-neutralizing the anionic polymer, thereby decreasing an anionic fixed charge in the polyelectrolyte bilayer; or
chemically crosslinking the cationic polymer with the anionic polymer, thereby decreasing both a cationic fixed charge and an anionic fixed charge in the polyelectrolyte bilayer.

2. The method of claim 1 , wherein the cationic polymer comprises an amine group.

3. The method of claim 2 , wherein the amine group comprises a primary or quaternary amine group.

4. The method of claim 2 , wherein the chemically crosslinking comprises crosslinking the amine groups of the cationic polymer with an amine-reactive crosslinker to form amine-to-amine bonds.

5. The method of claim 1 , wherein the anionic polymer comprises a carboxylic acid group or sulfonate group.

6. The method of claim 5 , further comprising charge-neutralizing the carboxylic acid groups of the anionic polymer with carboxylate-reactive agent.

7. The method of claim 1 , wherein the cationic polymer comprises an amine group and the anionic polymer comprises a carboxylic acid group.

8. The method of claim 7 , wherein the chemically crosslinking comprises crosslinking the amine groups of the cationic polymer with the carboxylic acid groups of the anionic polymer to form amide bonds.

9. The method of claim 8 , wherein the amine groups of the cationic polymer are chemically crosslinked with the carboxylic acid groups of the anionic polymer with a carbodiimide crosslinker.

10. The method of claim 7 , wherein cationic polymer comprises poly(ethyleneimine) and the anionic polymer comprises poly(acrylic acid).

11. The method of claim 10 , wherein the chemically crosslinking comprises crosslinking the amine groups of the poly(ethyleneimine), thereby decreasing a cationic fixed charge in the polyelectrolyte bilayer.

12. The method of claim 11 , wherein the poly(ethyleneimine) is crosslinked with glutaraldehyde.

13. The method of claim 10 , further comprising wherein the chemically crosslinking comprises crosslinking amine groups of the poly(ethyleneimine) with carboxylic acid groups of the poly(acrylic acid).

14. The method of claim 13 , wherein the poly(ethyleneimine) and the poly(acrylic acid) are crosslinked with N-(3-dimethylaminopropyl)-N′-ethylcarbodimide hydrochloride.

15. The method of claim 1 , where the at least polyelectrolyte bilayer comprises at least three polyelectrolyte bilayers.

16. The method of claim 1 , wherein the layer-by-layer depositing step comprises sequential dip coating of the cationic polymer layer and the anionic polymer layer.

17. The method of claim 1 , wherein the cationic polymer or anionic polymer or both further comprises at least one biomolecule.

18. The method of claim 17 , wherein the at least one biomolecule comprises an amino acid or peptide.

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Small Leo J
• Percival Stephen
• Spoerke Erik David

Classifications

• B01D69/125

  In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction · CPC title

• B01D61/461

  comprising only a single cell, only one anion or cation exchange membrane or one pair of anion and cation membranes · CPC title

• B01D71/401

  Polymers based on the polymerisation of acrylic acid, e.g. polyacrylate · CPC title

• B01D69/1216

  Three or more layers · CPC title

• B01D71/601

  Polyethylenimine · CPC title