Aerogels and methods of making same
Provided in one embodiment is a method of making an aerogel, comprising: (A) increasing a concentration of a suspension comprising a gel precursor under a condition that promotes formation of a gel, wherein the gel precursor comprises particulates having an asymmetric geometry; and (B) removing a liquid from the gel to form the aerogel, wherein the aerogel and the gel have substantially the same geometry. An aerogel comprising desirable properties are also provided.
1. A method of making, comprising:
(A) increasing a concentration of a suspension comprising a gel precursor under a condition that promotes formation of a gel, wherein the gel precursor comprises particulates having an asymmetric geometry, and the particulates in the formed gel are physically bonded by Van der Waals forces; and
(B) removing a liquid from the gel to form an aerogel,
wherein the aerogel and the gel have substantially the same geometry.
2. The method of claim 1 , wherein the gel precursor comprises a metal, an oxide, a nitride, a sulfide, a semiconductor, a carbon-containing material, or combinations thereof.
3. The method of claim 1 , wherein the particulates have an aspect ratio of greater than about 50.
4. The method of claim 1 , wherein (A) further comprises increasing the concentration above a gel network transition point.
5. The method of claim 1 , wherein (A) further comprises removing a surfactant from the suspension.
6. The method of claim 1 , wherein the particulates in the gel substantially do not aggregate.
7. The method of claim 1 , wherein (A) further comprises forming the gel precursor into the gel by hydrothermal synthesis.
8. The method of claim 1 , wherein (B) is carried out by at least one of (i) freeze drying and (ii) supercritical point drying.
9. A method of making, comprising:
(A) subjecting a suspension comprising a gel precursor comprising particulates to at least one of sonication and filtering;
(B) forming the suspension into a gel using hydrothermal synthesis; and
(C) removing a liquid from the gel to form an aerogel,
wherein at least some of the particulates have an aspect ratio of at least 50.
10. The method of claim 9 , wherein (B) further comprises controlling at least one of an initial concentration of the gel precursor and a reaction time of the hydrothermal synthesis to affect formation of the gel.
11. The method of claim 10 , wherein the aerogel and the gel have substantially the same volume.
12. The method of claim 1 , wherein the gel precursor consists essentially of the particulates and an optional surfactant.