Methods and blends for controlling rheology and transition temperature of liquid crystals

• US 7,108,801 B2
• Filed: 01/23/2002
• Issued: 09/19/2006
• Est. Priority Date: 01/23/2001
• Status: Expired due to Term

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Hanson, Douglas P., Wellinghoff, Stephen T.
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US10/057,506
• Publication Number:
  US 20030036609A1
• Time in Patent Office: 1,700 Days
• Field of Search: 252/299.01, 252/299.64, 252/299.67, 252/299.65, 523115-117, 524/533, 524/559
• US Class Current: 252/299.01
• CPC Class Codes: C09K 19/20 linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
• CPC Class Codes: C09K 19/2007 the chain containing -COO- or -OCO- groups
• CPC Class Codes: C09K 19/52 characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
• CPC Class Codes: C09K 2019/2078 Ph-COO-Ph-COO-Ph
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: Y10S 585/935 Halogen-containing

Abstract

A method for producing a blend comprising randomly substituted mesogens comprising: providing one or more platform molecules have the following general structure:

wherein at least one member selected from the group consisting of X and Y comprises one or more spacer groups; R² is a bulky organic group whereby, when both X and Y are reacted with polymerizable groups to produce polymerizable mesogens, R² provides sufficient steric hindrance to achieve a nematic state at room temperature while suppressing crystallinity of the polymerizable mesogens at room temperature; and, R¹ and R³ are selected from groups less bulky than R²; and independently substituting at least one member selected from the group consisting of X and Y with a polymerizable group, thereby producing a blend of randomly substituted mesogens.

Claims

1. A method for producing a blend comprising:

providing a first phenylene ring consisting essentially of a first functional group at a para-position to a first halogenated carboxylic group;

providing a second phenylene ring consisting essentially of a second functional group at a para-position to a second halogenated carboxylic group;

providing a third phenylene ring comprising R² and comprising a first functionality at a para-position to a second functionality; and

forming a mixture comprising said first phenylene rings, said second phenylene rings, and said third phenylene rings;

exposing said mixture to first conditions effective to react said first halogenated carboxylic group with said first functionality to produce a first ester bond, said first conditions being effective to react said second halogenated carboxylic group with said second functionality to produce a second ester bond, producing a reaction product comprising said first functional group at position para- to said first ester bond and said second functional group at a position para- to said second ester bond; and

treating said reaction product under second conditions effective to produce platform molecules having the following general structure;

2. The method of claim 1 wherein the blend has a T_c of from about 20°

C. to about 37°

C.

3. The method of claim 2 wherein the blend has a Δ

T of about 10°

C. or more and one member selected from the group consisting of X and Y comprises a polymerizable group in about 50 wt. % or more of said blend.

4. The method of claim 1 wherein the blend has a Δ

T of about 10°

C. or more and one member selected from the group consisting of X and Y comprises a polymerizable group in about 70 wt. % or more of said blend.

5. The method of claim 1 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

6. The method of claim 3 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

7. The method of claim 4 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

8. The method of claim 3 comprising producing said blend having a Δ

T of about 20°

C. or more.

9. The method of claim 3 comprising producing said blend having a Δ

T of about 30°

C. or more.

10. The method of claim 7 comprising producing said blend having a Δ

T of about 20°

C. or more.

11. The method of claim 7 comprising producing said blend having a Δ

T of about 30°

C. or more.

12. A method for producing a blend comprising:

providing a first phenylene ring consisting essentially of a first functional group at a para-position to a first halogenated carboxylic group;

providing a second phenylene ring consisting essentially of a second functional group at a para-position to a second halogenated carboxylic group;

providing a third phenylene ring comprising R² and comprising a first functionality at a para-position to a second functionality; and

forming a mixture comprising said first phenylene rings, said second phenylene rings, and said third phenylene rings;

exposing said mixture to first conditions effective to react said first halogenated carboxylic group with said first functionality to produce a first ester bond, said first conditions being effective to react said second halogenated carboxylic group with said second functionality to produce a second ester bond, producing a reaction product comprising said first functional group at position para- to said first ester bond and said second functional group at a position para- to said second ester bond, one or more of said first functional group and said second functional group being selected from the group consisting of H—

(CH₂)_n—

O—

groups, Cl(CH₂)_n—

O—

groups, Br(CH₂)_n—

O—

groups, derivatives thereof, wherein n is from about 2 to about 12 and CH₂ independently is selected from the group consisting of CH₂ which is unsubstituted and CH₂ which is substantially by an element selected from the group consisting of oxygen, sulfur, and an ester group;

provided that at least 2 carbon atoms separates said oxygen or said ester group; and

treating said reaction product under second conditions effective to hydrolyze said first functional group and said second functional group, producing platform molecules having the following general structure;

13. The method of claim 12 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 60 wt. % of said blend.

14. The method of claim 12 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 70 wt. % of said blend.

15. The method of claim 12 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

16. The method of claim 12 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

17. The method of claim 14 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

18. The method of claim 12 comprising producing said blend having a Δ

T of about 20°

C. or more.

19. The method of claim 12 comprising producing said blend having a Δ

T of about 30°

C. or more.

20. The method of claim 17 comprising producing said blend having a Δ

T of about 20°

C. or more.

21. The method of claim 17 comprising producing said blend having a Δ

T of about 30°

C. or more.

22. The method of claim 12 wherein said second conditions comprise heating said reaction product in an aprotic solvent in the presence of water and potassium bromide to produce a reaction mixture comprising said platform molecules.

23. The method of claim 12 wherein said third conditions comprise

recrystallizing said platform molecules from said reaction mixture;

and,

reacting one or more of X and Y in recrystallized platform molecules with halogenated carboxyl group comprising a polymerizable group.

24. The method of claim 22 wherein said third conditions comprise

recrystallizing said platform molecules from said reaction mixture;

and,

reacting one or more of X and Y in recrystallized platform molecules with halogenated carboxyl group comprising a polymerizable group.

25. A method of producing a blend comprising:

providing 4 alkoxy benzoyl chloride molecules comprising benzyl chloride groups at a position para- to alkyl ether groups;

providing R²-hydroquinone molecules comprising first hydroxyl groups and second hydroxyl groups at para-positions;

forming a mixture comprising said 4-alkoxy benzoyl chloride molecule and said R² hydroquinone molecules; and

,

exposing said mixture to first conditions effective to react a first benzoyl chloride group on a first 4-alkoxy benzoyl chloride molecule with said first hydroxyl group to produce a first ester bond, said first conditions being effective to react a second benzoyl chloride group on a second 4-alkoxy-benzoyl chloride molecule with said second hydroxyl group to produce a second ester bond, producing a reaction product comprising said first alkyl ether group at a position para- to said first ester bond and said second alkyl ether group at a position para- to said second ester bond;

treating said bis terminal alkoxy groups under second conditions effective to cleave at least one of said first alkyl ether group and said second alkyl ether group to produce a reaction product comprising one or more platform molecules have the following general structure;

26. The method of claim 25 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 50 wt % or more of said blend, said blend having a T_c from about 20°

C. to about 37°

C. and a Δ

T of about 10°

C.

27. The method of claim 26 wherein the second conditions comprise a quantity of nucleophile and an amount of Lewis acid effective to cleave at least one of said first alkyl ether group and said second alkyl ether group.

28. The method of claim 27 wherein said quantity of nucleophile and said amount of Lewis acid also are effective to precipitate said platform molecules from said reaction product.

29. The method of claim 27 wherein:

said nucleophile is thiol and said quantity of nucleophile is about 1 mole of thiol or more per mole of alkyl ether;

said Lewis acid is aluminum chloride at a ratio of about 4;

1 to said alkyl ether.

30. The method of claim 28 wherein:

said nucleophile is thiol and said quantity of nucleophile is about 1 mole of thiol or more per mole of alkyl ether;

said Lewis acid is aluminum chloride at a ratio of about 4;

1 to said alkyl ether.

31. The method of claim 30 wherein said second conditions further comprise a molar excess of halogenated solvent in relation to the quantity of thiol, the molar excess being sufficiently high to maintain precipitated platform molecules in slurry form.

32. The method of claim 31 wherein said molar excess is from about 3 to about 7 molar excess in relation to the quantity of thiol.

33. The method of claim 32 wherein said molar excess is about 5 or more in relation to the quantity of thiol.

34. The method of claim 33 wherein the halogenated solvent is dichloromethane.

35. The method of claim 26 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 60 wt. % or more of said blend.

36. The method of claim 26 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 70 wt. % or more of said blend.

37. The method of claim 31 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 60 wt. % or more of said blend.

38. The method of claim 34 wherein one member selected from the group consisting of X and Y comprises a polymerizable group in about 70 wt. % or more of said blend.

39. The method of claim 26 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

40. The method of claim 31 wherein said moiety comprises polymerizable groups selected from the group consisting of acryloyl groups, methacryloyl groups, and cinnamoyl groups.

41. The method of claim 26 comprising producing said blend having a Δ

T of about 20°

C. or more.

42. The method of claim 26 comprising producing said blend having a Δ

T of about 30°

C. or more.

43. The method of claim 31 comprising producing said blend having a Δ

T of about 20°

C. or more.

44. The method of claim 31 comprising producing said blend having a Δ

T of about 30°

C. or more.