Self-assembled surfactant structures
Stabilized surfactant-based membranes and methods of manufacture thereof. Membranes comprising a stabilized surfactant mesostructure on a porous support may be used for various separations, including reverse osmosis and forward osmosis. The membranes are stabilized after evaporation of solvents; in some embodiments no removal of the surfactant is required. The surfactant solution may or may not comprise a hydrophilic compound such as an acid or base. The surface of the porous support is preferably modified prior to formation of the stabilized surfactant mesostructure. The membrane is sufficiently stable to be utilized in commercial separations devices such as spiral wound modules.
1. A membrane comprising a stabilized surfactant mesostructure bonded to a functionalized top surface of a porous plastic support, said stabilized surfactant mesostructure comprising surfactant molecules, wherein the functionalized top surface comprises at least one of a grafted top surface, a covalently modified top surface, an adsorption modified top surface, or an oxidized top surface and an alignment of surfactant molecules in the stabilized surfactant mesostructure enables transport across the stabilized surfactant mesostructure.
2. The membrane of claim 1 wherein said stabilized surfactant mesostructure is stabilized with a material preserving an alignment of surfactant molecules.
3. The membrane of claim 2 wherein said material is porous and said stabilized surfactant mesostructure comprises lamellae which alternate with lamellae comprising said porous material.
4. The membrane of claim 2 wherein said material is non-porous and said stabilized surfactant mesostructure comprises hexagonally packed columns comprising circularly arranged surfactant molecules, each of said columns substantially surrounded by said non-porous material.
5. The membrane of claim 1 further comprising a material disposed between said stabilized surfactant mesostructure and said functionalized surface for preserving a hydrogen bonding network of the stabilized surfactant mesostructure.
6. The membrane of claim 5 wherein said material comprises a material selected from the group consisting of silanes, organics, inorganics, metals, metal oxides, an alkyl silane, calcium, and silica.
7. The membrane of claim 1 wherein said functionalized surface has been oxidized, melted and resolidified prior to bonding of said stabilized surfactant mesostructure on said functionalized surface.
8. The membrane of claim 7 wherein an average pore size at said resolidified functionalized surface is smaller than average pore size in a bulk of said porous support.
9. The membrane of claim 1 wherein a pore size of said porous support is sufficiently small to prevent a precursor solution to said stabilized surfactant mesostructure from completely permeating the support prior to formation of stabilized surfactant mesostructure.
10. The membrane of claim 1 further comprising an additional porous structure disposed on a side of said porous plastic support opposite from said functionalized surface for mechanically or chemically stabilizing said porous plastic support.
11. The membrane of claim 1 wherein said stabilized surfactant mesostructure comprises a transporter.
12. The membrane of claim 1 further comprising a second porous support, wherein said stabilized surfactant mesostructure is sandwiched between said porous plastic support and said second porous support.
13. The membrane of claim 1 comprising a tortuosity of less than approximately 1.09.
14. The membrane of claim 1 wherein said stabilized surfactant mesostructure comprises a pore size between approximately 0.3 Angstroms and approximately 4 nm.
15. The membrane of claim 1 comprising a porosity greater than approximately 1%.
16. The membrane of claim 1 wherein said porous plastic support comprises cellulose.
17. The membrane of claim 1 further comprising a second stabilized surfactant mesostructure bonded to a side of said porous plastic support opposite from said functionalized surface.
18. The membrane of claim 1 stacked with other membranes of claim 1 , thereby forming a multilayer membrane.
19. The membrane of claim 1 comprising an ion-exchange membrane or a gas diffusion layer or both, said membrane comprising a membrane electrode assembly or an electrolyte.
20. The membrane of claim 1 wherein said porous plastic support mechanically stabilizes said stabilized surfactant mesostructure.