Liquid-crystalline medium
The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having a negative dielectric anisotropy which contains at least one self-aligning additive, especially at least one additive selected from the group of the compounds of the formula IA to ID in which R 1A , R 1B , R 1C , L 1-12 , R 1D , Ring l, u, v, w, x, y, z and m have the meanings indicated in Claim 4 and to the use thereof for an active-matrix display, in particular based on the VA, PSA and PS-VA effect in LC displays.
1. A liquid-crystalline medium comprising a mixture of polar compounds having a negative dielectric anisotropy and at least one self-aligning additive of the formula 1A to 1D,
in which
R 1A , R 1B and R 1C each, independently of one another, denote halogen, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—,
—CO—O—, —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
R 1D H, halogen, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CF 2 O—, —CH═CH—, —CO—O—, —O—CO—
in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by halogen,
denotes
L 1 to L 12 each, independently of one another, denote H, F, Cl, CF 3 , CHF 2 or alkyl with 1-5 carbon atoms, preferably F or alkyl,
m 0, 1, 2, 3, 4, 5 or 6, and
u, v, w, x, y and z each, independently denote 0 or 1.
2. The liquid-crystalline medium according to claim 1 , further comprising at least one polymerizable compound.
3. The liquid-crystalline medium according to claim 1 comprising 0.01 to 5% by weight of the self-aligning additive based on the mixture.
4. The liquid-crystalline medium according to claim 1 , wherein the self-aligning additive is a compound of the formula
5. The liquid-crystalline medium according to claim 2 , the polymerizable compound is a compound of formula M
R Ma -A M1 -(Z M1 -A M2 ) m1 -R Mb M
in which the individual radicals have the following meanings:
R Ma and R Mb each, independently of one another, denote P, P-Sp-, H, halogen, SF 5 , NO 2 , an alkyl, alkenyl or alkynyl group,
P denotes a polymerisable group,
Sp denotes a spacer group or a single bond,
A M1 and A M2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 ring atoms, preferably C atoms, which may also encompass or contain fused rings, and which may optionally be mono- or polysubstituted by L,
L denotes P, P-Sp-, OH, CH 2 OH, F, Cl, Br, I, —CN, —NO 2 , —NCO, —NCS, —OCN, —SCN, —C(═O)N(R x ) 2 , —C(═O)Y 1 , —C(═O)R x , —N(R x ) 2 , optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-,
Y 1 denotes halogen,
Z M1 denotes —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH 2 —, —CH 2 O—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —(CH 2 ) n1 —, —CF 2 CH 2 —, —CH 2 CF 2 —, —(CF 2 ) n1 —, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—, —COO—, —OCO—CH═CH—, CR 0 R 00 or a single bond,
R 0 and R 00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms,
R x denotes P, P-Sp-, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms,
m1 denotes 0, 1, 2, 3 or 4, and
n1 denotes 1, 2, 3 or 4,
where at least one, of R Ma , R Mb or L present denotes a group P or P-Sp- or contains at least one group P or P-Sp-.
6. The liquid-crystalline medium according to claim 5 , wherein the polymerizable compound of the formula M is of the of formula M1 to M29,
in which the individual radicals have the following meanings:
P 1 and P 2 each, independently of one another, denote a polymerisable group,
Sp 1 and Sp 2 each, independently of one another, denote a single bond or a spacer group, where one of the radicals P 1 -Sp 1 - and P 2 -Sp 2 - may also denote R aa ,
R aa denotes H, F, Cl, CN or straight-chain or branched alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH 2 groups may each be replaced, independently of one another, by —C(R 0 )═C(R 00 )—, —C≡C—, —N(R 0 )—, —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— in such a way that O and/or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 -, (where the alkenyl and alkynyl radicals have at least two C atoms and the branched radicals have at least three C atoms),
R 0 , R 00 each, independently of one another and on each occurrence identically or differently, denote H or alkyl having 1 to 12 C atoms,
R y and R z each, independently of one another, denote H, F, CH 3 or CF 3 ,
Z M1 denotes —O—, —CO—, —C(R y R z )— or —CF 2 CF 2 —,
Z M2 and Z M3 each, independently of one another, denote
—CO—O—, —O—CO—, —CH 2 O—, —OCH 2 —, —OCF 2 — or —(CH 2 ) n —, where n is 2, 3 or 4,
L on each occurrence, identically or differently, denotes F, Cl, CN, or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1 to 12 C atoms,
L′ and L″ each, independently of one another, denote H, F or Cl,
r denotes 0, 1, 2, 3 or 4,
s denotes 0, 1, 2 or 3,
t denotes 0, 1 or 2, and
x denotes 0 or 1.
7. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of the formulae IIA, IIB and IIC
in which
R 2A , R 2B and R 2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
L 1-4 each, independently of one another, denote F, Cl, CF 3 or OCF 2
Z 2 and Z 2′ each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —CF═CF—, —CH═CHCH 2 O—,
(O)C v H 2v+1 denotes OC v H 2v+1 or C v H 2v+1
p denotes 1 or 2,
q denotes 0 or 1, and
v denotes 1 to 6.
8. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of the formula III,
in which
R 31 and R 32 each, independently of one another, denote a straight-chain alkyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, and
denotes
Z 3 denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —C 4 H 9 —, —CF═CF—.
9. The liquid-crystalline medium according to claim 1 , additionally comprising at least one compound of the formulae L-1 to L-11,
in which
R, R 1 and R 2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another and alkyl denotes an alkyl radical having 1-6 C atoms,
(O)-alkyl denotes O-alkyl or alkyl, and
s denotes 1 or 2.
10. The liquid-crystalline Liquid-crystalline medium according to claim 1 , additionally comprising one or more terphenyls of the formulae T-1 to T-21,
in which
R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms,
(O)C m H 2m+1 denotes OC m H 2m+1 or C m H 2m+1 , and
m denotes 1-6.
11. The liquid-crystalline medium according to claim 1 , additionally comprising one or more compounds of the formulae O-1 to O-16,
in which
R 1 and R 2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3 or at least monosubstituted by halogen, where, in addition, one or more CH 2 groups in these radicals may be replaced by —O—, —S—,
—C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another.
12. The liquid-crystalline medium according to claim 1 , additionally comprising one or more indane compounds of the formula In,
in which
R 11 , R 12 , R 13 denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1-5 C atoms,
R 12 and R 13 additionally also denote H or halogen,
denotes
i denotes 0, 1 or 2.
13. A process for the preparation of a liquid-crystalline medium according to claim 1 , comprising mixing at least one self-aligning compound with at least two liquid-crystalline compounds, and optionally with at least one polymerizable compound and optionally with one or more additives.
14. A self-aligning VA mode, electro-optical display, comprising the liquid-crystalline medium according to claim 1 .
15. An electro-optical display having active-matrix addressing, comprising as dielectric, a liquid-crystalline medium according to claim 1 .
16. An electro-optical display according to claim 15 , that is a VA, PSA or PS-VA display.
17. The liquid-crystalline medium according to claim 5 , where at least one of the radicals R Ma and R Mb denotes or contains a group P or P-Sp-.
18. The liquid-crystalline medium according to claim 5 , wherein L is P, P-Sp-, H, OH, CH 2 OH, halogen, SF 5 , NO 2 , an alkyl, alkenyl or an alkynyl group.
19. The liquid-crystalline medium according to claim 6 , wherein P 1 and P 2 are independently an acrylate, methacrylate, fluoroacrylate, oxetane, vinyloxy or epoxy group, and
Sp 1 and Sp 2 are each independently —(CH 2 ) p1 —, —(CH 2 ) p1 —O—, —(CH 2 ) p1 —CO—O— or —(CH 2 ) p1 —O—CO—O—, in which p1 is an integer from 1 to 12, and where the linking of the last-mentioned groups to the adjacent ring takes place via the O atom.
20. The liquid-crystalline medium according to claim 6 , wherein R aa is a straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl or alkylcarbonyloxy having 1 to 12 C atoms.