US 12,291,621 B2
Fabrication of aerogels and aerogel composites by ambient pressure sublimation of frozen solvents
Massimo Bertino, Glen Allen, VA (US); and Tyler Selden, Richmond, VA (US)
Assigned to Virginia Commonwealth University, Richmond, VA (US)
Appl. No. 17/621,278
Filed by VIRGINIA COMMONWEALTH UNIVERSITY, Richmond, VA (US)
PCT Filed Jun. 25, 2020, PCT No. PCT/US2020/039485
§ 371(c)(1), (2) Date Dec. 21, 2021,
PCT Pub. No. WO2020/264070, PCT Pub. Date Dec. 30, 2020.
Claims priority of provisional application 62/868,228, filed on Jun. 28, 2019.
Prior Publication US 2022/0356320 A1, Nov. 10, 2022
Int. Cl. C08J 9/28 (2006.01)
CPC C08J 9/28 (2013.01) [C08J 2201/0484 (2013.01); C08J 2205/026 (2013.01); C08J 2205/06 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method of preparing an aerogel, comprising:
preparing a wet gel containing a gelation solvent;
exchanging the gelation solvent with a drying solvent in the wet gel, wherein the drying solvent does not form hydrogen bonds with pore walls of the wet gel or aerogel and is a solvent with a freezing point near an ambient temperature between 10° C. and 200° C., and a vapor pressure near ambient pressure between 0.005 Torr and 10 Torr;
freezing the drying solvent in the wet gel below its freezing temperature to produce a gel with frozen drying solvent; and
removing frozen drying solvent from the gel by exposing the gel to a vacuum, dry air, or dry inert gases, wherein the step of removing the frozen drying solvent results in gel shrinkage of >0% and <10%.