US5922299A
Expired / Lapsed
US
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Mesoporous-silica films, fibers, and powders by evaporation
Assignee: Battelle Memorial Institute Inc
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Filing: 1997-08-26
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Granted: 1999-07-13
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Expires: 2017-08-26
Abstract
Abstract This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s).
Inventors
- 👤 Paul J. Bruinsma
- 👤 Suresh Baskaran
- 👤 Jagannadha R. Bontha
- 👤 Jun Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:03
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/45; C04B41/4582; B; B01; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/103; B01J21/00; B01J21/06; B01J21/08; B01J37/00; B01J37/02; B01J37/0236; B01J37/03; B01J37/031; B01J37/033; C01; C01B; C01B37/00; C01B37/005; C01B37/02; C04B20/00; C04B20/0048; C04B20/0056; C04B35/00; C04B35/01; C04B35/14; C04B35/622; C04B35/62218; C04B38/00; C04B38/0022; C04B41/009; C04B41/80; C04B41/81
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
145 words
A method of making mesoporous silica materials, comprising the steps of (a) combining a silica precursor with an aqueous solvent, an acid and a surfactant having an ammonium cation into a silica precursor solution, (b) templating the silica precursor with the surfactant and obtaining the mesoporous material from the templated silica precursor, (c) forming said silica precursor solution into a preform; and (d) rapidly evaporating said aqueous solvent from said preform for obtaining the mesoporous material, wherein the improvement comprises: (i) providing said aqueous solvent in an amount resulting in complete hydrolysis and providing said acid in an amount maintaining a hydrolyzed precursor and avoiding gelation or precipitation; and (ii) providing said surfactant and said silica precursor in a mole ratio that is above a lower mole ratio that produces a non-porous silica phase and below an upper mole ratio that produces a lamellar phase.
Claim 2
Independent Claim
145 words
A method of making mesoporous silica materials, comprising the steps of (a) combining a silica precursor with an aqueous solvent, an acid and a surfactant having an ammonium cation into a silica precursor solution, (b) templating the silica precursor with the surfactant and obtaining the mesoporous material from the templated silica precursor, (c) forming said silica precursor solution into a preform; and (d) rapidly evaporating said aqueous solvent from said preform for obtaining the mesoporous material, wherein the improvement comprises: (i) providing said aqueous solvent in an amount resulting in complete hydrolysis and providing said acid in an amount maintaining a hydrolyzed precursor and avoiding gelation or precipitation; and (ii) providing said surfactant and said silica precursor in a mole ratio that is above a lower mole ratio that produces a non-porous silica phase and below an upper mole ratio that produces a lamellar phase.
Claim 3
Dependent Claim
15 words
The method as recited in claim 1, wherein said lower mole ratio is about 0.05.
Claim 4
Dependent Claim
15 words
The method as recited in claim 1, wherein said upper mole ratio is about 0.3.
Claim 5
Dependent Claim
31 words
The method as recited in claim 1, wherein said acid is added in an amount resulting in a pH of said silica precursor solution of from about 1 to about 4.
Claim 6
Dependent Claim
13 words
The method as recited in claim 4, wherein said pH is about 2.
Claim 7
Dependent Claim
17 words
The method as recited in claim 1, wherein the step of forming includes diluting with an alcohol.
Claim 8
Dependent Claim
12 words
The method as recited in claim 6, wherein said alcohol is ethanol.
Claim 9
Dependent Claim
24 words
The method as recited in claim 1, wherein said aqueous solvent, said acid, and said surfactant are premixed before combining with said silica precursor.
Claim 10
Dependent Claim
26 words
The method as recited in claim 1, wherein said mesoporous material is in a geometric form selected from the group consisting of fiber, powder, and film.
Claim 11
Dependent Claim
12 words
The method as recited in claim 1, wherein said forming is spin-casting.
Claim 12
Dependent Claim
12 words
The method as recited in claim 1, wherein said forming is spraying.
Claim 13
Dependent Claim
24 words
The method as recited in claim 1, further comprising adding a pre-polymer or a polymer to said silica precursor solution making a pituitous mixture.
Claim 14
Dependent Claim
12 words
The method as recited in claim 1, wherein said forming is drawing.
Claim 15
Dependent Claim
12 words
The method as recited in claim 1, wherein said forming is squeegeeing.
Claim 16
Dependent Claim
21 words
The method as recited in claim 1, further comprising the step of adding a metal compound to the silica precursor solution.
Claim 17
Dependent Claim
25 words
The method as recited in claim 15, wherein said metal compound is selected from the group consisting of metal halide, metal nitrate, and combinations thereof.
Claim 18
Dependent Claim
15 words
The method as recited in claim 16, wherein said metal halide is a metal chloride.
Claim 19
Dependent Claim
21 words
The method as recited in claim 16, wherein said metal is selected from the group of aluminum, iron and combinations thereof.
Claim 20
Dependent Claim
19 words
The method as recited in claim 1, wherein said silica precursor is an alkoxide silica precursor or a tetrachlorosilane.
Claim 21
Dependent Claim
28 words
The method as recited in claim 1, wherein said aqueous solvent amount is characterized by a ratio of said aqueous solvent to said silica precursor of about 7.
Claim 22
Dependent Claim
26 words
The method as recited in claim 1, wherein said acid amount is characterized by a ratio of said acid to said silica precursor of about 0.1.
Claim 23
Dependent Claim
18 words
The method as recited in claim 1, further comprising adding a swelling agent to the silica precursor solution.
Claim 24
Dependent Claim
13 words
The method as recited in claim 22, wherein said swelling agent is 1,3,5-thimethylbenzene.
Claim 25
Dependent Claim
16 words
The method as recited in claim 1, further comprising the step of calcining the mesoporous material.
Claim 26
Independent Claim
157 words
A method of making a mesoporous silica film, comprising the steps of (a) combining a silica precursor with an aqueous solvent, an acid and a surfactant having an ammonium cation into a silica precursor solution, (b) templating the silica precursor with the surfactant and obtaining the mesoporous material from the templated silica precursor, (c) forming said silica precursor solution into a preform; and (d) rapidly evaporating said aqueous solvent from said preform for obtaining the mesoporous material, wherein the improvement comprises: (i) said silica precursor is tetraethoxysilane; (ii) providing said aqueous solvent in a superstoichiometric amount and providing said acid in an amount maintaining a hydrolyzed precursor and avoiding gelation or precipitation; (iii) providing said surfactant and said silica precursor in a mole ratio that is above a lower mole ratio that produces a non-porous silica phase and below an upper mole ratio that produces a lamellar phase; and (iv) said forming includes diluting with an alcohol.
Claim 27
Independent Claim
157 words
A method of making a mesoporous silica film, comprising the steps of (a) combining a silica precursor with an aqueous solvent, an acid and a surfactant having an ammonium cation into a silica precursor solution, (b) templating the silica precursor with the surfactant and obtaining the mesoporous material from the templated silica precursor, (c) forming said silica precursor solution into a preform; and (d) rapidly evaporating said aqueous solvent from said preform for obtaining the mesoporous material, wherein the improvement comprises: (i) said silica precursor is tetraethoxysilane; (ii) providing said aqueous solvent in a superstoichiometric amount and providing said acid in an amount maintaining a hydrolyzed precursor and avoiding gelation or precipitation; (iii) providing said surfactant and said silica precursor in a mole ratio that is above a lower mole ratio that produces a non-porous silica phase and below an upper mole ratio that produces a lamellar phase; and (iv) said forming includes diluting with an alcohol.
Claim 28
Dependent Claim
24 words
The method as recited in claim 26, further comprising adding a pre-polymer or a polymer to said silica precursor solution making a pituitous mixture.
Claim 29
Dependent Claim
14 words
The method as recited in claim 26, wherein said rapidly evaporating is by spin-casting.
References Cited (Backward Citations)
No citation records indexed.
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| 3.5 Years (Year 4) | 2002-07-12 | 2003-01-11 | 2003-07-13 | $2000.00 | Window Closed / Lapsed |
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