Liquid crystal elastomers

Patent metadata

Field	Value
Publication number	US-11926686-B2
Application number	US-202117533226-A
Country	US
Kind code	B2
Filing date	Nov 23, 2021
Priority date	Oct 15, 2018
Publication date	Mar 12, 2024
Grant date	Mar 12, 2024

Abstract

Shape-programmable liquid crystal elastomers. The shape-programmable liquid crystal elastomers being synthesized by filling an alignment cell with liquid crystal monomers. The liquid crystal monomers align to a surface of the alignment cell and then are polymerized with a dithiol chain transfer agent. The alignment cell is configured to impose a director orientation on a portion of the shape-programmable liquid crystal elastomer. For some embodiments, liquid crystal elastomer laminates are prepared by arranging a plurality of liquid crystal elastomers such that a director orientation of each liquid crystal elastomer of the plurality is in registered alignment with an adjacent liquid crystal elastomer of the plurality. The arrangement is secured and the plurality of liquid crystal elastomers cured.

First claim

What is claimed is:

1. A method of synthesizing a shape-programmable liquid crystal elastomer, the method comprising:
filling an alignment cell with liquid crystal monomers comprising a mixture of a first mesogenic diacrylate and a second mesogenic diacrylate at a ratio that suppresses nematic-crystallization phase transition, wherein the liquid crystal monomers align to a surface of the alignment cell; and
polymerizing the liquid crystal monomers with a dithiol chain transfer agent,
wherein the alignment cell is configured to impose a director orientation on a portion of the shape-programmable liquid crystal elastomer.

2. The method of claim 1 , wherein the liquid crystal monomers are mesogenic diacrylates.

3. The method of claim 2 , wherein the mesogenic diacrylate is selected from the group consisting of 1,4-bis[4-(3-acryloxyloxybutyloxy)benzoyloxy]-2-methylbenzene, 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methobenzene), and 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene.

4. The method of claim 1 , wherein the dithiol chain transfer agent is a C2-C6 alkyl-dithiol.

5. The method of claim 4 , wherein the dithiol chain transfer agent is selected from the group consisting of ethane dithiol, propane dithiol, hexane dithiol, and 1,4-benezenedimethanethiol.

6. The method of claim 1 , wherein an amount of thiol incorporated into the liquid crystal elastomer ranges from about 30% to about 50% by weight.

7. The method of claim 1 , further comprising:
introducing a photoinitiator before filling the alignment cell.

8. The method of claim 7 , wherein the photoinitiator is 2, 2-dimethoxy-2-phenylacetophenone.

9. The method of claim 7 , wherein the photoinitiator and liquid crystal monomers are melted before filling the alignment cell.

10. The method of claim 1 , wherein polymerizing liquid crystal monomers with a dithiol chain transfer agent includes applying ultraviolet light.

11. The method of claim 1 , wherein the filled alignment cell is cooled before the liquid crystal monomers are polymerized.

Assignees

• Us Gov Air Force
• Us Air Force

Inventors

• Godman Nicholas P
• White Timothy J
• Koerner Hilmar
• Kowalski Benjamin A
• Auguste Anesia D
• Guin Tyler C

Classifications

• C08F222/20 Primary

  Esters containing oxygen in addition to the carboxy oxygen · CPC title

• C08J5/121

  by heating · CPC title

• C09D135/02

  Homopolymers or copolymers of esters (C09D135/06, C09D135/08 take precedence) · CPC title

• C08F2800/20

  as weight or mass percentages · CPC title

• C08F2810/20

  leading to a crosslinking, either explicitly or inherently · CPC title