High optical transparency polymer aerogels using low refractive index monomers

Patent metadata

Field	Value
Publication number	US-10995191-B2
Application number	US-201816228472-A
Country	US
Kind code	B2
Filing date	Dec 20, 2018
Priority date	Dec 20, 2018
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A polymer aerogel has polymerizable monomers and crosslinkers, wherein at least one of the monomers or at least one of the crosslinkers has a refractive index of less than 1.5, and the polymer aerogel has a visible transmittance of at least 20%/3 mm, a haze of 50%/3 mm or lower, and a porosity of at least 10%. A method of producing an aerogel includes dissolving precursors into a solvent, wherein the precursors include monomers, crosslinkers, a controlling agent and an initiator to form a precursor solution, wherein at least one of the monomers or at least one of the crosslinkers has a refractive index of 1.5 or lower, polymerizing the precursor solution to form a gel polymer, and removing the solvent from the gel polymer to produce an aerogel polymer.

First claim

What is claimed is:

1. A polymer aerogel comprising polymerized monomers and crosslinkers, wherein at least one of the monomers or at least one of the crosslinkers has a refractive index of less than 1.45, and the polymer aerogel has a visible transmittance of at least 20%/3 mm, a haze of 50%/3 mm or lower, and a porosity of at least 10%.

2. The polymer aerogel of claim 1 , wherein the at least one of the monomers or the at least one of the crosslinkers has a refractive index of less than 1.4.

3. The polymer aerogel of claim 1 , wherein the polymer aerogel has a porosity of at least 40%, haze of 30%/3 mm or lower, and a specific surface area of at least 500 m 2 /g.

4. The polymer aerogel of claim 1 , wherein the polymer aerogel has a haze below 6%/3 mm, a specific surface area above 300 m 2 /g, a porosity above 20%, average pore size below 10 nm, and pore size distribution with full width at half maximum below 10 nm.

5. The polymer aerogel of claim 1 , wherein the polymer aerogel has a degradation onset temperature above 250° C.

6. The polymer aerogel of claim 1 , wherein the polymer aerogel has thermal conductivity below 0.1 W/mK.

7. A polymer aerogel manufactured from the process of:
dissolving precursors into a solvent, wherein the precursors include monomers, crosslinkers, a controlling agent and an initiator to form a precursor solution, wherein at least one of the monomers or at least one of the crosslinkers has a refractive index of 1.4 or lower;
polymerizing the precursor solution to form a gel polymer; and
removing the solvent from the gel polymer to produce an aerogel polymer.

8. The polymer aerogel as claimed in claim 1 , wherein the at least one monomer or at least one crosslinker has a stiffness of at least 3.5 GPa for the Young's modulus when polymerized.

9. The polymer aerogel as claimed in claim 1 , wherein the at least one monomer or the at least one crosslinker comprises one selected from the group consisting of: divinylbenzene; hexanediol diacrylate; hexanediol dimethacrylate, trimethacrylate, adamantane, and dipentaerythritol pentacrylate.

10. The polymer aerogel as claimed in claim 1 , wherein the at least one of the monomers or the at least one of the crosslinkers having a refractive index of 1.45 or lower comprises at least one selected from the group consisting of: 1H, 1H, 6H, 6H-Per-fluoro-1,6-hexanediol diacrylate (F-HDDA), 2,3,4,5,6-pentafluorostyrene, 1H, 1H, 2H-Perfluoro-l-hexene, ethylene glycol diacrylate, 1,1,1,3,3,3-Hexafluoroisopropyl methacrylate, 2,2,2-Trifluoroethyl methacrylate, 1, 1, 1,3,3,3-Hexafluoroisopropyl acrylate, 2,2,2-Trifluoroethyl acrylate, methacrylate-functionalized perfluoropolyethers, and acrylate-functionalized perfluoropolyethers.

11. The polymer aerogel as claimed in claim 8 , wherein the polymer aerogel comprises at least one monomer or at least one crosslinker with a refractive index of less than 1.45 comprising 30-99.9 vol % of the polymerizable monomers and crosslinkers.

12. The polymer aerogel of claim 1 , wherein the polymer aerogel has a porosity of at least 40%, haze of 15%/3 mm or lower, and a specific surface area of at least 600 m 2 /g.

13. The polymer aerogel of claim 1 , wherein the polymer aerogel comprises at least 20 wt % of fluorine.

14. The polymer aerogel of claim 1 , wherein the aerogel includes a control agent.

15. The polymer aerogel of claim 14 , wherein the control agent comprises at least one selected from the group consisting of: a chain transfer agent, an organic thiol chain transfer agent, dodecanethiol, chloroform, octyl mercaptan, and 1,8-dimercapto-3,6-dioxaoctane.

16. The polymer aerogel of claim 14 , wherein the control agent comprises at least one selected from the group consisting of: reagents to enable stable free radical polymerization, a stable nitroxide, an alkoxyamine, 2,2,6,6-Tetramethyl-1-piperidinyloxy (TEMPO), and 4-hydroxy-TEMPO.

17. The polymer aerogel of claim 14 , wherein the control agent comprises at least one selected from the group consisting of: a reagent capable of mediating a RAFT polymerization, a trithiocarbonate chain transfer agent, a xanthate chain transfer agent, a benzodithioate chain transfer agent, and a ligand-coordinated transition metal ion capable of mediating an ATRP polymerization.

18. The polymer aerogel of claim 1 , wherein the polymer aerogel includes at least a portion of an initiator or at least a portion of a chain transfer agent.

Assignees

• Palo Alto Res Ct Inc
• Palo Alto Res Center Incoporated

Inventors

• Bulger Eli
• Chintapalli Mahati
• Iftime Gabriel
• Van Overmeere Quentin
• Rivest Jessica Louis Baker
• Neelakantan Ravi
• Meckler Stephen

Classifications

• C08J2300/102

  containing halogen atoms · CPC title

• C08J2205/026

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

• C08J2201/0542

  from an organic solvent-based polymer composition · CPC title

• C08J2201/05

  Elimination by evaporation or heat degradation of a liquid phase · CPC title

• C08J2201/026

  Crosslinking before of after foaming · CPC title