Membrane comprising self-assembled block copolymer and process for producing the same by hybrid casting (IIb)

Patent metadata

Field	Value
Publication number	US-9592476-B2
Application number	US-201414292446-A
Country	US
Kind code	B2
Filing date	May 30, 2014
Priority date	May 30, 2014
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

Disclosed are membranes formed from self-assembling block copolymers, for example, a diblock copolymer of the formula (I):

wherein R 1 -R 4 , n, and m are as described herein, which find use in preparing nanoporous membranes. Embodiments of the membranes contain the block copolymer that self-assembles into a cylindrical morphology. Also disclosed is a method of preparing such membrane which involves hybrid casting a polymer solution containing the block copolymer to obtain a thin film, followed by evaporation of some of the solvent from the thin film, and coagulating the resulting this film in a bath containing a nonsolvent or poor solvent for the block copolymer.

First claim

The invention claimed is:

1. A method of preparing a porous membrane comprising a block copolymer of the formula (I) or (II):

wherein:
R 1 is a C 1 -C 22 alkyl group optionally substituted with a substituent selected from halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro, or a C 3 -C 11 cycloalkyl group, optionally substituted with a substituent selected from halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro;
R 2 is a C 6 -C 20 aryl group or a heteroaryl group, optionally substituted with a substituent selected from hydroxy, nitro, amino, halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro;
one of R 3 and R 4 is a C 6 -C 14 aryl group, optionally substituted with a substituent selected from hydroxy, halo, amino, and nitro, and the other of R 3 and R 4 is a C 1 -C 22 alkoxy group, optionally substituted with a substituent selected from carboxy, amino, mercapto, alkynyl, alkenyl, halo, azido, and heterocyclyl;
n and m are independently about 10 to about 2000; 0<x≦n and 0<y≦m;
wherein the volume fraction of the monomeric unit bearing R 2 to that of the monomeric unit bearing R 1 in the block copolymer is about 2.3 to about 5.6:1;
wherein the porous membrane has cylindrical morphology;

the method comprising:
(i) dissolving the block copolymer in a solvent system to obtain a polymer solution;
(ii) coating the polymer solution onto a substrate;
(iii) evaporating at least a portion of a solvent from the coating obtained in (ii);
(iv) immersing the coating from (iii) into a coagulation bath; and
(v) washing the porous membrane obtained in (iv).

2. The method of claim 1 , wherein R 1 is a C 10 -C 18 alkyl group, optionally substituted with a substituent selected from halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro.

3. The method of claim 1 , wherein R 2 is a phenyl group, optionally substituted with a substituent selected from hydroxy, amino, halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro.

4. The method of claim 1 , wherein R 3 is phenyl.

5. The method of claim 1 , wherein R 4 is a C 1 -C 6 alkoxy group.

6. The method of claim 1 , wherein n is about 10 to about 200 and m is about 50 to about 2000.

7. The method of claim 1 , wherein n is about 83 to about 190 and m is about 675 to about 1525.

8. The method of claim 1 , wherein n is about 105 and m is about 870.

9. The method of claim 1 , wherein the block copolymer of formula (I) has the following structure:

10. The method of claim 1 , wherein the solvent system includes a solvent or a mixture of solvents selected from halogenated hydrocarbons, ethers, amides, and sulfoxides.

11. The method of claim 1 , wherein the solvent system includes a solvent or a mixture of solvents selected from dichloromethane, 1-chloropentane, chloroform, 1,1-dichloroethane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, tetrahydrofuran, 1,3-dioxane, and 1,4-dioxane.

12. The method of claim 1 , wherein the polymer solution contains about 10 to about 35% by weight of the block copolymer.

13. The method of claim 1 , wherein the substrate is selected from glass, silicon wafer, metal plate, plastic film, woven or nonwoven fabric, and a plastic film coated on a glass substrate or on or a silicon wafer.

14. The method of claim 1 , wherein the substrate is porous.

15. The method of claim 1 , wherein the coagulation bath comprises a nonsolvent or poor solvent for the block copolymer.

16. The method of claim 15 , wherein the nonsolvent or poor solvent is selected from alcohols, alkanes, water, dimethylsulfoxide, and mixtures thereof.

17. A porous membrane prepared by the method of claim 1 .

18. The porous membrane of claim 17 , which is an asymmetric membrane comprising a first layer and a second layer, the first layer comprising the block copolymer and ordered pores in a cylindrical morphology continuously extending to the second layer comprising the block copolymer in a network of porous structure in which micro and macro channels are connected so as to provide a tortuous path for fluid flow.

19. The porous membrane of claim 18 , wherein the first layer has a thickness of about 50 to about 200 nm and the second layer has a thickness of about 100 μm to about 300 μm.

Assignees

• Pall Corp

Inventors

• Aamer Khaled Abdel-Hakim Helmy
• Grzenia David Lukas

Classifications

• B01D71/52

  Polyethers · CPC title

• B01D67/0016

  Coagulation · CPC title

• C08G2261/614

  for liquids · CPC title

• C08G2261/1412

  Saturated aliphatic units · CPC title

• C08G2261/148

  Side-chains having aromatic units · CPC title