Liquid-crystal compositions comprising chiral compounds
View Patent ↗The invention relates to a class of compounds useful as chiral dopants, which compounds are available in both enantiomeric forms, in liquid-crystal formulations. Such formulations are advantageous in displays and various other products.
1. A liquid-crystalline composition comprising as a chiral dopant admixed with a liquid-crystal material, at least one chiral compound, or a polymerized form thereof, represented by the following structure:
wherein A, B, C, and D are independently selected divalent groups, the X groups are independently selected substituents, the n subscripts are independently 0, 1, 2, or 3, and the R O groups are independently hydrogen or a substituent capping each oxygen, and wherein any two X and/or R 0 groups can optionally form a fused ring and the two R 0 groups can optionally connect to form a bridge, wherein Structure 1 excludes macrocyclic compounds containing two or more structural units based on Structure 1.
2. The composition of claim 1 wherein A, B, C, and D is independently selected from the group consisting of methylene, oxygen, sulfur, sulfoxyl, sulfonyl, carbonyl, mono-substituted nitrogen (N—R), and di-substituted carbon (R 1 —C—R 2 ), wherein R, R 1 and R 2 are independently hydrogen or a substituent and any two R, R 1 and R 2 groups on the same ring in said structure can optionally form a fused ring.
3. The composition of claim 2 wherein A, B, C, and D are independently methylene or di-substituted carbon (R 1 —C—R 2 ).
4. The composition of claim 1 wherein A and B are the same, respectively, as C and D.
5. The composition of claim 1 wherein each X substituent is independently selected from the group consisting of oxygen-containing organic substituents and/or a carbon-containing substituents.
6. The composition of claim 5 wherein each X is independently selected from the group consisting of alkoxy, aryloxy, carboalkyl (O—C(═O)R), carboaryl (O—C(═O)Ar), carboalkoxy (O—C(═O)OR), carboaryloxy (O—C(═O)OAr), alkyl groups of about 1–20 carbons, cycloalkyl groups of about 1–20 carbons, aryl groups of about 6–20 carbons, alkaryl groups of about 6–20 carbons, carboalkoxy (C—C(═O)OR), carboaryloxy (C—C(═O)OAr), aryl or alkyl ketones (C—C(═O)R) or (C—C(═O)Ar), all either substituted or unsubstituted, or any two members of the X and R 0 groups on a ring may be joined to form a fused ring; Ar is an aryl group and R is an independently hydrogen or substituent.
7. The composition of claim 1 represented by the following structure:
wherein each R CO is an independently selected substituent and each R 1 and R 2 are independently hydrogen or an alkyl substituent.
8. The composition of claim 7 wherein R CO is aryl, alkyl, cycloalkyl, alkaryl or heterocyclic, all either substituted or unsubstituted.
9. The composition of claim 1 wherein the compound is a polymerization product of compounds of Structure 1 that are capable of polymerization.
10. The liquid-crystalline composition of claim 1 further comprising a polymer binder in which domains of the liquid crystal are dispersed.
11. The liquid-crystalline composition of claim 1 wherein the liquid-crystalline composition is STN, TN, chiral nematic, or ferroelectric.
12. The liquid-crystalline composition of claim 1 wherein the liquid-crystalline composition is chiral nematic.
13. A coated substrate comprising the liquid-crystalline composition of claim 1 .
14. A display comprising the liquid-crystalline composition of claim 1 wherein the composition is disposed between first and second electrodes.
15. The display of claim 14 wherein the liquid-crystalline composition is bistable and dispersed in the form of domains in a polymeric matrix.