Additive manufacturing of hierarchical three-dimensional micro-architected aerogels

Patent metadata

Field	Value
Publication number	US-2021237344-A1
Application number	US-201917049934-A
Country	US
Kind code	A1
Filing date	Apr 5, 2019
Priority date	Apr 24, 2018
Publication date	Aug 5, 2021
Grant date	—

Abstract

Disclosed here is a method for making a three-dimensional micro-architected aerogel, comprising: (a) curing a reaction mixture comprising a co-sol-gel material (e.g., graphene oxide (GO)) and at least one catalyst to obtain a crosslinked co-sol-gel (e.g., GO hydrogel); (b) providing a photoresin comprising a solvent, a photoinitiator, a crosslinkable polymer precursor, and a dispersion of the crosslinked co-sol-gel (e.g., GO hydrogel); (c) curing the photoresin using projection microstereolithography layer-by-layer to produce a wet gel having a pre-designed three-dimensional structure; (d) drying the wet gel to produce a dry gel; and (e) pyrolyzing the dry gel to produce a three-dimensional micro-architected aerogel (e.g., graphene aerogel). Also disclosed is a photoresin for projection microstereolithography, comprising a solvent, a photoinitiator, a crosslinkable polymer precursor, and a dispersion of a crosslinked co-sol-gel.

First claim

1 . A method for making a three-dimensional micro-architected aerogel, comprising:
(a) curing a reaction mixture comprising a co-sol-gel material and at least one catalyst to obtain a crosslinked co-sol-gel; (b) providing a photoresin comprising a solvent, a photoinitiator, a crosslinkable polymer precursor, and a dispersion of the crosslinked co-sol-gel; (c) curing the photoresin using projection microstereolithography layer-by-layer to produce a wet gel having a pre-designed three-dimensional structure; (d) drying the wet gel to produce a dry gel; and (e) pyrolyzing the dry gel to produce a three-dimensional micro-architected aerogel.

2 . The method of claim 1 , wherein the co-sol-gel material is graphene oxide (GO), resorcinol formaldehyde (RF), melamine formaldehyde (MF), or a metal organic framework (MOF).

3 . The method of claim 1 , wherein the solvent comprises an organic solvent.

4 . The method of claim 1 , wherein the solvent comprises N,N-dimethylformamide (DMF).

5 . The method of claim 1 , wherein the photoinitiator is soluble in an organic solvent.

6 . The method of claim 1 , wherein the photoinitiator comprises phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irg819).

7 . The method of claim 1 , wherein the crosslinkable polymer precursor comprises a non-aromatic acrylate prepolymer and an aromatic acrylate prepolymer, and wherein the crosslinkable polymer precursor accounts for about 12-30 wt. % of the photoresin.

8 . The method of claim 1 , wherein the crosslinkable polymer precursor comprises polyethylene glycol diacrylate (PEGDA) and Bisphenol A ethoxylate (2 EO/phenol) dimethacrylate (BisA-EDMA).

9 . The method of claim 1 , wherein the catalyst comprises ammonium hydroxide.

10 . The method of claim 1 , wherein step (a) comprises curing the reaction mixture at a temperature of 100° C. or less.

11 . The method of claim 1 , wherein step (b) comprises washing the crosslinked co-sol-gel by solvent exchange, dispersing the crosslinked co-sol-gel in the solvent by sonication, and adding the photoinitiator and the crosslinkable polymer precursor to the dispersion of the crosslinked co-sol-gel.

12 . The method of claim 1 , wherein step (c) comprises curing the photoresin at a wavelength of 500 nm or less.

13 . The method of claim 1 , wherein step (d) comprises solvent exchange, supercritical drying, and/or freeze drying.

14 . The method of claim 1 , wherein step (e) comprises pyrolyzing in an inert environment at a temperature of 800° C. or more.

15 . The method of claim 1 , further comprising the step of (f) CO 2 etching the three-dimensional micro-architected aerogel.

16 . A three-dimensional micro-architected aerogel produced by the method of claim 1 .

17 . The three-dimensional micro-architected aerogel of claim 16 , having a density of 200 mg/cm 3 or less and an electrical conductivity of at least 10 S/m.

18 . The three-dimensional micro-architected aerogel of claim 16 , having a density of 200 mg/cm 3 or less and a surface area of at least 100 m 2 /g.

19 . The three-dimensional micro-architected aerogel of claim 16 , having a density of 200 mg/cm 3 or less and an elastic modulus of at least 5 MPa.

20 . The three-dimensional micro-architected aerogel of claim 16 , having a scaling factor of less than 2 based on log-log plot of density versus elastic modulus.

21 . The three-dimensional micro-architected aerogel of claim 16 , comprising a first order structure of gyroid lattices and, optionally, a second order structure of octet-truss lattices.

22 . A photoresin for projection microstereolithography, comprising a solvent, a photoinitiator, a crosslinkable polymer precursor, and a dispersion of a crosslinked co-sol-gel.

Assignees

• Zheng Xiaoyu
• L Livermore Nat Security Llc

Inventors

• Worsley Marcus A
• Zheng Xiaoyu
• Campbell Patrick G
• Duoss Eric
• Oakdale James
• Spadaccini Christopher
• HENSLEIGH Ryan

Classifications

• C01B2204/26

  Mechanical properties · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title

• C01P2006/10

  Solid density · CPC title

• C01B32/194

  After-treatment · CPC title

• C08J2205/026

  Aerogel, i.e. a supercritically dried gel · CPC title