Porous membrane and method of making the same
View Patent ↗A method of making a porous membrane is disclosed. One such method optionally includes: forming a plurality of pillars in an array form over a substrate; and forming a layer with a mixture of a porous material precursor and a surfactant over the substrate. The method optionally includes removing the pillars to leave cavities in the layer; filling the cavities in the layer with a cavity filler; and removing the surfactant from the layer. The porous membrane can be used as, for example, a sieve for separating molecules from a chemical reaction.
1. A method of making a porous membrane, the method comprising:
forming an array of pillars over a substrate; and
depositing a layer onto the substrate, the layer including a mixture of a porous material precursor and a surfactant, wherein the mixture is configured to self-arrange around the arrayed pillars, and wherein the mixture forms pores in the layer;
removing the pillars to leave one or more cavities in the layer;
filling the one or more cavities in the layer with a cavity filler; and
solidifying the layer.
2. The method of claim 1 , wherein solidifying the layer comprises removing the surfactant.
3. The method of claim 1 , wherein solidifying the layer comprises calcining the layer.
4. The method of claim 3 , wherein calcining the layer comprises heating the porous layer to about 450° C. to about 550° C.
5. The method of claim 1 , wherein the substrate comprises silicon.
6. The method of claim 1 , wherein forming the pillars comprises forming the pillars with a hydrophobic material.
7. The method of claim 6 , wherein the hydrophobic material comprises a photoresist.
8. The method of claim 1 , wherein at least one of the arrayed pillars has a height between about 100 nm and about 1 μm, and a width between about 100 nm and about 10 μm.
9. The method of claim 1 , wherein a distance between two adjacent pillars is between about 100 nm and about 1 μm.
10. The method of claim 1 , wherein a distance between two or more adjacent pillars is the same.
11. The method of claim 1 , wherein the forming the array of pillars comprises patterning the pillars in a geometric pattern on the substrate.
12. The method of claim 11 , wherein the geometric pattern comprises two or more rows of pillars.
13. The method of claim 12 , wherein the geometric pattern comprises two or more columns of pillars.
14. The method of claim 12 , wherein the geometric pattern comprises two or more diagonal lines of pillars.
15. The method of claim 1 , wherein the precursor comprises one or more precursors for forming Mobile Crystalline Material (MCM)-41 or Santa Barbara Amorphous-15 (SBA-15).
16. The method of claim 1 , wherein the precursor comprises one or more materials selected from the group consisting of a metal oxide, silicon-aluminum oxide, and a silicate.
17. The method of claim 16 , wherein the metal oxide comprises one or more selected from the group consisting of titanium oxide (TiO 2 ), zirconium oxide (ZrO 2 ), and niobium oxide (Nb 2 O 5 ).
18. The method of claim 16 , wherein the silicate comprises one or more selected from the group consisting of tetraethylorthosilicate (TEOS) and sodium silicate.
19. The method of claim 1 , wherein the surfactant includes a hydrophobic portion.
20. The method of claim 1 , wherein the surfactant is amphiphilic.
21. The method of claim 1 , wherein the surfactant extends laterally from the pillars.
22. The method of claim 1 , wherein the surfactant comprises one or more selected from the group consisting of cetyltrimethylammonium bromide (CTAB), alkyltrimethylammonium bromide (C n TMAB; where n is an integer equal to or greater than 14), P123 polymer, and F127 polymer.
23. The method of claim 1 , wherein the pores have an average diameter between about 2 nm and about 50 nm.
24. A method of making a porous membrane, the method comprising:
forming an array of pillars over a substrate;
depositing a layer onto the substrate, the layer including a mixture of a porous material precursor and a surfactant, wherein the mixture is configured to self-arrange around the arrayed pillars, and wherein the mixture forms pores in the layer;
removing the pillars to leave one or more cavities in the layer; and
filling the one or more cavities in the layer with a cavity filler, wherein the cavity filler is the same as the mixture of the precursor and the surfactant.
25. A method of making a porous membrane, the method comprising:
forming an array of pillars over a substrate;
depositing a layer onto the substrate, the layer including a mixture of a porous material precursor and a surfactant, wherein the mixture is configured to self-arrange around the arrayed pillars, and wherein the mixture forms pores in the layer;
removing the pillars to leave one or more cavities in the layer; and
filling the one or more cavities in the layer with a cavity filler, wherein the cavity filler is different from the mixture of the precursor and the surfactant.
26. The method of claim 25 , wherein the cavity filler is a precursor material for forming silicon oxide.
27. The method of claim 1 , further comprising attaching the layer onto a support substrate, wherein the support substrate includes pores having a diameter equal to or greater about 50 nm.
28. The method of claim 27 , wherein the support substrate comprises anodic aluminum oxide.
29. The method of claim 27 , wherein attaching the layer onto a support substrate comprises attaching the layer after filling the one or more cavities and before removing the surfactant.
30. The method of claim 1 , further comprising removing the substrate from the layer.
31. The method of claim 1 , further comprising attaching molecules to an inner surface of the pores.
32. The method of claim 1 , wherein the attaching molecules comprises attaching one or more molecules selected from the group consisting of a polynucleotide, a polypeptide, a branched or unbranched C1-C30 alkyl group, and a compound comprising an alkoxide group.
33. The method of claim 32 , wherein the polynucleotide comprises a hairpin DNA.