High optical transparency polymer aerogels using low refractive index monomers

Patent metadata

Field	Value
Publication number	US-2021309822-A1
Application number	US-202117245418-A
Country	US
Kind code	A1
Filing date	Apr 30, 2021
Priority date	Dec 20, 2018
Publication date	Oct 7, 2021
Grant date	—

Abstract

A method of producing a polymer 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 the polymer aerogel. A method of producing a polymer aerogel include dissolving precursors into a solvent, wherein the precursors include monomers, crosslinkers, a controlling agent and an initiator to form a precursor solution, polymerizing the precursor solution to form a gel polymer, removing the solvent from the gel polymer to produce the polymer aerogel, and reducing a refractive index of one of either the gel polymer or the polymer aerogel.

First claim

What is claimed is:

1 . A method of producing a polymer aerogel, comprising:
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 the polymer aerogel.

2 . The method of claim 1 , wherein the at least one of the monomers or the at least one of the crosslinkers has a refractive index below 1.4.

3 . The method of claim 1 , wherein the precursors include at least one monomer or at least one crosslinker that has a stiffness of at least 3.5 GPa.

4 . The method of 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.

5 . The method of claim 1 , wherein the at least one of the monomers or the at least one of the crosslinkers having a refractive index of 1.5 or lower comprises at least one selected from the group consisting of: 1H, 1H, 6H, 6H-Perfluoro-1, 6-hexanediol diacrylate (FHDDA), 2, 3, 4, 5, 6-pentafluorostyrene, 1H, 1H, 2H-Perfluoro-1-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, methacrylatefunctionalized perfluoropolyethers, and acrylate-functionalized perfluoropolyethers.

6 . The method of claim 1 , wherein the initiator comprises at least one selected from the group consisting of: a thermal initiator, AIBN, lauroyl peroxide, benzoyl peroxide, tert-butyl peroxide, dicumyl peroxide, a photoinitiator, benzophenone, anthraquinone, camphorquinone, and benzoin.

7 . The method of claim 1 , 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.

8 . The method of claim 1 , 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, 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.

9 . The method of claim 1 , wherein the polymerizable precursors comprise 0.1-70 vol % of the precursor solution.

10 . The method of claim 1 , wherein the initiator comprises 0.001-10 wt % of the precursor solution.

11 . The method of claim 1 , wherein the control agent comprises 0.0001-10 wt % of the precursor solution.

12 . The method of claim 1 , wherein the at least one low refractive index monomer or the at least one crosslinkers comprise 0.1-70 vol % of the polymerizable precursors.

13 . The method of claim 1 , wherein monomers having a stiffness of at least 3.5 GPa and crosslinkers comprise 30-99.9 vol % of the polymerizable precursors.

14 . The method of claim 1 , wherein polymerizing comprises one of either heating the precursor solution to a temperature between 50 and 150° C. for a period of time of at least 1 min, or exposure to electromagnetic radiation.

15 . The method of claim 1 , further comprising drying the gel polymer by one of ambient drying, freeze drying, or supercritical CO 2 drying.

16 . A method of producing a polymer aerogel, comprising:
dissolving precursors into a solvent, wherein the precursors include monomers, crosslinkers, a controlling agent and an initiator to form a precursor solution; polymerizing the precursor solution to form a gel polymer; removing the solvent from the gel polymer to produce the polymer aerogel; and reducing a refractive index of one of either the gel polymer or the polymer aerogel.

17 . The method as claimed in claim 16 , wherein reducing a refractive index of the polymer aerogel occurs after one of either removing the solvent or drying the polymer aerogel.

18 . The method as claimed in claim 16 , wherein reducing the refractive index comprises modifying the polymer gel or the polymer aerogel with one of fluorine, fluorine-containing chemical groups, or siloxane-containing chemical groups.

19 . An aerogel produced from the method as claimed in claim 16 ,

20 . An 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 1.5 or lower; polymerizing the precursor solution to form a gel polymer; and removing the solvent from the gel polymer to produce the aerogel polymer.

Assignees

• Palo Alto Res Ct Inc

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

• C08J3/242

  Applying crosslinking or accelerating agent onto compounding ingredients such as fillers, reinforcements · CPC title

• C08J2205/044

  Micropores, i.e. average diameter being between 0,1 micrometer and 0,1 millimeter · CPC title

• C08J2201/05

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

• C08J2201/0542

  from an organic solvent-based polymer composition · CPC title