Microporous materials

• US 5,238,613 A
• Filed: 02/12/1992
• Issued: 08/24/1993
• Est. Priority Date: 05/20/1987
• Status: Expired due to Fees

• Current Assignee: David M. Anderson
• Original Assignee: David M. Anderson
• Inventors: Anderson, David M.
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US07/835,019
• Time in Patent Office: 559 Days
• Field of Search: 210/500.35, 210/500.27, 210/500.23, 264/41, 264/49, 264/22
• US Class Current: 264/425
• CPC Class Codes: A61F 2/15 Implant having one or more holes, e.g. for nutrient transport, for facilitating handling
• CPC Class Codes: B01D 2323/18 Pore-control agents or pore formers
• CPC Class Codes: B01D 2323/34 Use of radiation
• CPC Class Codes: B01D 2325/02 Details relating to pores or porosity of the membranes
• CPC Class Codes: B01D 2325/026 Sponge structure
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 2325/10 Catalysts being present on the surface of the membrane or in the pores
• CPC Class Codes: B01D 2325/42 Ion-exchange membranes
• CPC Class Codes: B01D 67/0006 by chemical reactions in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0031 by elimination of at least one of the blocks of a block copolymer
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/141 Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
• CPC Class Codes: B01D 69/1411 containing dispersed material in a continuous matrix
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
• CPC Class Codes: C12N 11/087 Acrylic polymers
• CPC Class Codes: C12N 2710/00051 Methods of production or purification of viral material
• CPC Class Codes: C12N 7/00 Viruses; Bacteriophages; Compositions thereof; Preparation or purification thereof preparing medicinal viral antigen or antibody compositions, e.g. virus vaccines, A61K39/00
• CPC Class Codes: H01M 8/1062 : characterised by the physical properties of the porous support, e.g. its porosity or thickness
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

A new type of polymeric microporous membrane has been synthesized which is distinguished by a highly-branched porespace morphology that is continuous and triply-periodic, and thus very precisely controlled and easily characterized. The membrane consists of a polymeric matrix containing pores of diameter on the order of 10 nm connected into a continuous pore network exhibiting long-range three-dimensional order. This long-range order is evidenced in small-angle X-ray scattering (SAXS) experiments by Bragg reflections that index to a triply-periodic space group, as well as in electron micrographs that match predictions from a theoretical model of the same space group and lattice parameter. The membrane combines three important features that have not been present simultaneously in any prior art membrane having pore diameters between 2 nm and 1 micron. First, the pores are identical in size and shape to a very high degree, and their size can be controlled in the synthesis. Second, the porespace is characterized by intricate branching and reconnections, with at least three pore throats meeting at a given pore body, this number (the coordination number) being the same for each pore body, and the porespace is isotropic in the cases where the space group is cubic. These two features allow accurately controlled sieving on the basis of particle size and shape, and provide highly accessible and precisely shaped pore bodies and surfaces for other applications such as catalysis, ion exchange, and the preparation of metal microstructures. And third, the membrane has a high porosity (approximately 90%).

Claims

1. A process of making a stabilized triply periodic porous material with a uniform pore size in which the pores bodies and pore throats are substantially identical in size and shape, comprising the steps of:

(a) distilling a mixture of methylmethacrylate and azoisobutyronitrile;

(b) mixing the product of (a) with a quantity of didodecyldimethyl ammonium bromide;

(c) adding a solvent to the mixture of (b);

(d) stirring the mixture of (c) until a viscous isotropic phase is formed;

(e) equilibrating said viscous isotropic phase for at least one week; and

(f) irradiating said equilibrated isotropic phase to cause radical chain polymerization of the methylmethacrylate and formation of a stabilized triply periodic porous material with uniform pore size in which the pore size bodies and pore size throats are substantially identical in size and shape.

2. A process as recited in claim 1, wherein the distillate is a mixture of at least 10% of methylmethacrylate at least 55% didodecyldimethyl ammonium bromide and 0.004 milligrams per milliliters of azoisobutyronitrile.

3. A process as recited in claim 2, wherein said solvent is a mixture of at least 35% water.

4. A process of making a stabilized triply periodic porous material with a uniform pore size in which the pore size bodies and pore size throats are substantially identical in size and shape, comprising the steps of:

(a) distilling an oleic compound mixed with a free radical source;

(b) mixing the product of (a) with a quantity of surfactant;

(c) adding a solvent aliquot to the mixture of (b);

(d) stirring the mixture of (c) until a viscous isotropic phase is formed;

(e) equilibrating said viscous isotropic phase; and

(f) providing a free radical initiator to said equilibrated viscous isotropic phase causing radical chain polymerization of said oleic compound by the decomposition of said free radical source and the formation of a stabilized triply periodic microporous material with uniform pore size in which the pore size bodies and pore size throats are substantially identical in size and shape.

5. A process as recited in claim 4, wherein said oleic compound is a hydrocarbon.

6. A process as recited in claim 5, wherein said hydrocarbon is aliphatic.

7. A process as recited in claim 4, wherein said surfactant is anionic.

8. A process as recited in claim 4, wherein said surfactant is cationic.

9. A process as recited in claim 4, wherein said free radical initiator is selected from the group consisting of:

(a) ultra violet light;

(b) thermal decomposition; and

(c) equivalents.