Additives for liquid-crystal mixtures

Abstract

The invention relates to liquid-crystal mixtures which comprise polyfluorinated additives, and to liquid-crystal displays based on these mixtures.

Claims

1. Liquid-crystalline medium comprising a liquid-crystalline component, characterised in that the liquid-crystalline medium comprises one or more self-alignment additives for vertical alignment and one or more additives of the following formula I: ##STR00495## in which R.sup.1 denotes a straight-chain or branched alkyl group having 1 to 20 C atoms, or H, where, in addition, one or more CH.sub.2 groups in this radical may each be replaced, independently of one another, by —C≡C—, —CH═CH—, ##STR00496##  —O—, —S—, —CO—O— or —O—CO— in such a way that O or S atoms are not linked directly to one another, R.sup.F denotes a polyfluorinated alkyl group with 4 to 25 carbon atoms having at least 9 fluorine atoms, Z.sup.1 independently denotes a single bond, —CH.sub.2CH.sub.2—, —COO—, trans-—CH═CH—, trans-—CF═CF—, —CH.sub.2O—, —CF.sub.2O— or —C≡C—, in which asymmetrical bridges may be oriented to both sides, and where two O atoms of adjacent groups are not connected directly, Sp.sup.1 denotes a single bond or —(CH.sub.2).sub.m—, in which m=1, 2, 3 or 4 and in which one or two CH.sub.2 groups may be replaced by —O— or —S— in such a way that O/S atoms are not linked directly to one another, Sp.sup.2 denotes a linear or branched, trivalent spacer, A.sup.1, independently of one another, denotes a radical selected from the following groups: a) the group consisting of trans-1,4-cyclohexylene and 1,4-cyclohexenylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and in which, in addition, one or more H atoms may be replaced by F or Cl, b) 1,4-phenylene, in which, in addition, one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by a group L or R.sup.2, and c) the group consisting of 2,6-naphthylene, dibenzofuran-3,7-diyl, dibenzothiophene-3,7-diyl, 9H-fluorene-2,7-diyl, phenanthrene-2,7-diyl, 6H-benzo[c]chromene-3,8-diyl, anthracene-2,6-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by a group L, A.sup.2 denotes a 6- or 5-membered saturated, unsaturated or aromatic, carbocyclic or heterocyclic ring system, which is in each case optionally additionally substituted by one or two groups L, L independently denotes F, Cl, —CN, an alkyl group having 1 to 5 C atoms, an alkoxy group having 1-5 C atoms or an alkenyl group having 2 to 5 C atoms, and n denotes 0, 1, 2, 3 or 4.

2. Liquid-crystal medium according to claim 1, characterised in that in formula I the group R.sup.F is a group selected from the formulae R.sup.2, ##STR00497## R.sup.2 in each case independently denotes ##STR00498## Rf.sup.1, Rf.sup.3 independently denote H, F, —CF.sub.3, —CF.sub.2CF.sub.3, —CF.sub.2CF.sub.2CF.sub.3 or CF(CF.sub.3).sub.2, Rf.sup.2 independently denotes an unbranched, branched or cyclic fluoroalkyl group having 3 to 15 fluorine atoms and 1 to 10 C atoms, in which one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S—,

3. Liquid-crystal medium according to claim 1, characterised in that the one or more self-alignment additives for vertical alignment comprise one or more unpolymerizable, polymerizable or polymerized compounds of formula II:
MES-R.sup.a  II in which MES is a calamitic mesogenic group comprising two or more rings, which are connected directly or indirectly to each other or which are condensed to each other, and which is substituted optionally by one or more polymerizable groups, which are connected to MES directly or via a spacer, and R.sup.a is a polar anchor group, residing in a terminal position of the calamitic mesogenic group MES which comprises at least one carbon atom and at least one group selected from —OH, —SH,  —COOH, —CHO or primary or secondary amine function and which optionally comprises one or two polymerizable groups P.

4. The liquid-crystalline medium according to claim 1, wherein said self-alignment additive for vertical alignment is of formula IIa
R.sup.1-[A.sup.2-Z.sup.2].sub.m-A.sup.1-R.sup.a  IIa in which A.sup.1, A.sup.2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by a group L or -Sp-P, L in each case, independently of one another, denotes H, F, Cl, Br, I, —CN, —NO.sub.2, —NCO, —NCS, —OCN, —SCN, —C(═O)N(R.sup.0).sub.2, —C(═O)R.sup.0, optionally substituted silyl, optionally substituted aryl or cycloalkyl having 3 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 25 C atoms, in which, in addition, one or more H atoms may each be replaced by F or Cl, P denotes a polymerizable group, Sp denotes a spacer group or a single bond, Z.sup.2 in each case, independently of one another, denotes a single bond, —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH.sub.2—, —CH.sub.2O—, —SCH.sub.2—, —CH.sub.2S—, —CF.sub.2O—, —OCF.sub.2—, —CF.sub.2S—, —SCF.sub.2—, —(CH.sub.2).sub.n1—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, —(CR.sup.0R.sup.00).sub.n1—, —CH(-Sp-P)—, —CH.sub.2CH(-Sp-P)—, or —CH(-Sp-P)CH(-Sp-P)—, n1 denotes 1, 2, 3 or 4, m denotes 0, 1, 2, 3, 4, 5 or 6, R.sup.0 in each case, independently of one another, denotes alkyl having 1 to 12 C atoms, R.sup.00 in each case, independently of one another, denotes H or alkyl having 1 to 12 C atoms, R.sup.1 independently of one another, denotes H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —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 each be replaced by F or Cl, or a group -Sp-P, and R.sup.a denotes a polar anchor group residing in a terminal position of the calamitic mesogenic group MES which comprises at least one carbon atom and at least one group selected from —OH, —SH, —COOH, —CHO or primary or secondary amine function and which optionally comprises one or two polymerizable groups P.

5. The liquid-crystalline medium according to claim 1, wherein said self-alignment additive has an anchor group R.sup.a which is selected from the formulae ##STR00499## wherein p denotes 1 or 2, q denotes 2 or 3, B denotes a substituted or unsubstituted ring system or condensed ring system, Y independently of one another, denotes —O—, —S—, —C(O)—, —C(O)O—, —OC(O)—, —NR.sup.11— or a single bond, o denotes 0 or 1, X.sup.1 independently of one another, denotes H, alkyl, fluoroalkyl, OH, NH.sub.2, NHR.sup.11, NR.sup.11.sub.2, OR.sup.11, C(O)OH, or —CHO, where at least one group X.sup.1 denotes a radical selected from —OH, —NH.sub.2, NHR.sup.11, C(O)OH and —CHO, R.sup.11 denotes alkyl having 1 to 12 C atoms, Sp.sup.a, Sp.sup.c, Sp.sup.d each, independently of one another, denote a spacer group or a single bond, and Sp.sup.b denotes a tri- or tetravalent group.

6. The liquid-crystalline medium according to claim 1, wherein said self-alignment additive for vertical alignment is selected from the compounds of formulae II-A to II-D, ##STR00500## in which R.sup.1 denotes H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, in which, in addition, one or more non-adjacent CH.sub.2 groups may each be replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —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 each be replaced by F or Cl, or a group -Sp-P, R.sup.a denotes a polar anchor group-residing in a terminal position of the calamitic mesogenic group MES which comprises at least one carbon atom and at least one group selected from —OH, —SH, —COOH, —CHO or primary or secondary amine function and which optionally comprises one or two polymerizable groups P, A.sup.2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by a group L or -Sp-P, Z.sup.2 in each case, independently of one another, denotes a single bond, —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH.sub.2—, —CH.sub.2O—, —SCH.sub.2—, —CH.sub.2S—, —CF.sub.2O—, —OCF.sub.2—, —CF.sub.2S—, —SCF.sub.2—, —(CH.sub.2).sub.n1—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n1—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, —(CR.sup.0R.sup.00).sub.n1—, —CH(-Sp-P)—, —CH.sub.2CH(-Sp-P)—, or —CH(-Sp-P)CH(-Sp-P)—, P denotes a polymerizable group, Sp denotes a spacer group or a single bond, L.sup.1 is F or alkyl, m 0, 1, 2 or 3, and r1 is 0, 1, 2, 3, or 4.

7. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of the formula III ##STR00501## in which R.sup.21 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, R.sup.22 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, ##STR00502## denotes ##STR00503## p and q each, independently of one another, denote 0, 1 or 2 and (p+q) denotes 1, 2 or 3.

8. Liquid-crystalline medium according to claim 1, characterised in that it additionally comprises one or more compounds of the formula V, ##STR00504## in which R.sup.41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, and R.sup.42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms.

9. Liquid-crystalline medium according to claim 1, characterised in that the total concentration of the compounds of the formula I in the entire medium is 0.001% by weight or more to 2% by weight or less.

10. Liquid-crystalline medium according to claim 1, characterised in that in formula I R.sup.F denotes a group selected from the formulae ##STR00505## and n denotes 0, 1 or 2.

11. Liquid-crystalline medium according to claim 1, wherein the one or more compounds of formula I is selected from the group of the compounds of the formulae IA to IF: ##STR00506##

12. Liquid-crystalline medium according to claim 1, characterised in that it comprises a proportion of polymerizable or polymerized compounds.

13. An electro-optical display comprising a liquid-crystal medium according to claim 1.

14. Process for the preparation of a liquid-crystalline medium according to claim 1, characterised in that one or more compounds each of the formula I and of formula II are mixed with one or more liquid-crystalline compounds, and further compounds and additives are optionally added.

15. Electro-optical display containing a liquid-crystal medium according to claim 12.

16. Process for the filling of an electro-optical display with a liquid-crystal medium, characterised in that the medium comprises one or more polyfluorinated additives of the formula I and a self-alignment additive for vertical alignment according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0189] FIG. 1 represents an image of two filled liquid-crystal test cells observed between crossed polarizers (initial alignment image). Black area indicates vertically aligned areas of the cells. The right side cell is filled according to Example 1 with a polyfluorinated additive, the left side cell contains a reference sample without the polyfluorinated additive.

[0190] FIG. 2 represents another initial alignment image in the manner of FIG. 1. The right side cell is filled according to Example 2 with a polyfluorinated additive, the left side cell contains a reference sample without the polyfluorinated additive.

EXAMPLES

[0191] The following examples are intended to explain the invention without limiting it. Above and below, percentage data denote percent by weight. All temperatures are indicated in degrees Celsius. Furthermore, C=crystalline state, N=nematic phase, Sm=smectic phase and I=isotropic phase. The data between these symbols represent the transition temperatures. Δn denotes the optical anisotropy (589 nm, 20° C.), Δε denotes the dielectric anisotropy (1 kHz, 20° C.) and γ.sub.1 denotes the rotational viscosity (in the unit mPa.Math.s).

[0192] Physical, physicochemical or electro-optical parameters are determined by generally known methods, as described, inter alia, in the brochure “Merck Liquid Crystals—Licristal®—Physical Properties of Liquid Crystals—Description of the Measurement Methods”, 1998, Merck KGaA, Darmstadt. Above and below, Δn denotes the optical anisotropy (589 nm, 20° C.) and Δε denotes the dielectric anisotropy (1 kHz, 20° C.). The dielectric anisotropy Δε is determined at 20° C. and 1 kHz. The optical anisotropy Δn is determined at 20° C. and a wavelength of 589.3 nm.

[0193] The Δε and Δn values and the rotational viscosity (γ.sub.1) of the compounds according to the invention are obtained by linear extrapolation from liquid-crystalline mixtures consisting of 5 to 10% of the respective compound according to the invention and 90-95% of the commercially available liquid-crystal mixture ZLI-4792 (for Δε>1, Δn, γ.sub.1) or ZLI-2857 (for Δε<1) (mixtures, Merck KGaA, Darmstadt).

SYNTHESIS EXAMPLES

Synthesis Example 1

[0194] ##STR00465##

[0195] 1c: Diisopropyl azodicarboxylate (4.70 ml, 23.9 mmol) is added dropwise to a solution of 1a (5.00 g, 20.3 mmol), 1b (5.53 g, 20.3 mmol) and triphenylphosphine (6.04 g, 23.0 mmol) in 50 ml of dry tetrahydrofuran (THF), during which the reaction temperature is held below 30° C. The reaction mixture is stirred overnight at room temperature. After the solvent has been separated off, the oily residue is purified by means of flash chromatography on silica gel with heptane/ethyl acetate, giving 1c as a colourless oil (5.8 g).

[0196] 1d: Palladium (5%) on active carbon (2.5 g) is added to a solution of 1c (5.2 g, 10.4 mmol) in 50 ml of THF, and the mixture is hydrogenated under hydrogen for 19 h. The catalyst is filtered off. After the solvent has been removed, the residue is purified by means of flash chromatography on silica gel with dichloromethane/methanol, giving 1d as a white solid (2.6 g).

[0197] 1: Diisopropyl azodicarboxylate (1.87 ml, 9.6 mmol) is added dropwise at 0° C. to a solution of 1d (1.03 g, 3.2 mmol) and triphenylphosphine (2.52 g, 9.6 mmol) in 25 ml of dry THF. After the mixture has been stirred for 30 min, perfluoro-tert-butanol (2.27 g, 9.6 mmol) is added, and the mixture is stirred overnight at 45° C. After the solvent has been separated off, the residue is purified by means of flash chromatography on silica gel with heptane/ethyl acetate, giving 1 as white crystals (1.0 g, m.p. 41° C.).

Synthesis Example 2

[0198] ##STR00466##

[0199] 2c: Diisopropyl azodicarboxylate (3.70 ml, 18.8 mmol) is added dropwise to a solution of 2a (2.50 g, 13.5 mmol), 2b (7.60 g, 27.0 mmol) and triphenylphosphine (8.00 g, 30.0 mmol) in 60 ml of THF, during which the reaction temperature is kept below 30° C. The reaction mixture is stirred overnight at room temperature. After the solvent has been separated off, the oily residue is purified by means of flash chromatography on silica gel with heptane/ethyl acetate, giving 2d as a colourless oil (2.1 g).

[0200] 2d: Sodium carbonate (0.9 g, 8.5 mmol) and 4 ml of distilled water are added to a solution of 2c (2.00 g, 2.9 mmol) and 4-pentylphenylboronic acid (0.60 g, 3.1 mmol) in 20 ml of 1,4-dioxane. After the mixture has been degassed using argon, [1,1′-bis(diphenylphosphine)ferrocene]palladium(II) dichloride (0.063 g, 0.09 mmol) is added. The reaction mixture is heated to reflux and stirred overnight. After conventional work-up, the collected organic phases are dried over sodium sulfate. After removal of the solvent, the residue is purified by means of flash chromatography on silica gel with heptane/ethyl acetate, giving 2d (2.0 g).

[0201] 2e: Palladium (5%) on active carbon (0.5 g) is added to a solution of 2d (2.0 g, 2.6 mmol) in 20 ml of THF, and the mixture is hydrogenated under hydrogen for 16 h. The catalyst is filtered off. After removal of the solvent, the residue is purified by means of flash chromatography on silica gel with dichloromethane/methanol, giving 2e as a colourless oil (1.0 g).

[0202] 2: Diisopropyl azodicarboxylate (2.43 ml, 12.4 mmol) is added dropwise at 0° C. to a solution of 2e (1.0 g, 2.5 mmol) and triphenylphosphine (2.72 ml, 12.4 mmol) in 50 ml of dry THF. After the mixture has been stirred for 30 min, perfluoro-tert-butanol (3.5 g, 14.8 mmol) is added, and the mixture is stirred overnight at 45° C. After the solvent has been separated off, the residue is purified by means of flash chromatography on silica gel with heptane/ethyl acetate. Recrystallisation of the crude product obtained from ethanol gives the product 2 as white crystals (1.0 g, melting point 46° C.).

[0203] The following are prepared analogously to Example 1 or 2:

Synthesis Example 3

[0204] ##STR00467##

[0205] Melting point 65° C. (C 65 I).

Synthesis Example 4

[0206] ##STR00468##

Synthesis Example 5

[0207] ##STR00469##

[0208] Melting point 40° C. (C 40 SmA (23) I)

Synthesis Example 6

[0209] ##STR00470##

[0210] Melting point 36° C. (C 36 I)

Synthesis Example 7

[0211] ##STR00471##

[0212] Mixture of the isomers prepared by catalytic hydrogenation of the product from Synthesis Example 2. Oil (main fraction: Tg−38° C. I)

Synthesis Example 8

[0213] ##STR00472##

[0214] Oil (Tg−19° C. I)

Synthesis Example 9

[0215] ##STR00473##

Synthesis Example 10

[0216] ##STR00474##

Synthesis Example 11

[0217] ##STR00475##

Synthesis Example 12

[0218] ##STR00476##

Synthesis Example 13

[0219] ##STR00477##

Synthesis Example 14

[0220] ##STR00478##

[0221] Oil.

[0222] .sup.1H NMR (500 MHz, chloroform-d) δ 7.55-7.41 (m, 2H), 7.27 (dd, J=7.7, 5.9 Hz, 2H), 6.84 (d, J=2.2 Hz, 2H), 6.56 (t, J=2.2 Hz, 1H), 4.59 (p, J=4.8 Hz, 2H), 4.15-3.97 (m, 8H), 3.95-3.85 (m, 8H), 2.67 (dd, J=8.7, 6.9 Hz, 2H), 1.74-1.63 (m, 2H), 1.46-1.34 (m, 4H), 0.97-0.87 (m, 3H).

Synthesis Example 15

[0223] ##STR00479##

Synthesis Example 16

[0224] ##STR00480##

Synthesis Example 17

[0225] ##STR00481##

[0226] Oil.

[0227] .sup.1H NMR (chloroform-d) δ 7.55-7.45 (m, 2H), 7.27 (dd, J=7.6, 5.8 Hz, 2H), 6.77 (d, J=2.2 Hz, 2H), 6.45 (t, J=2.2 Hz, 1H), 6.04 (dt, J=54.4, 3.8 Hz, 2H), 4.27 (t, J=6.5 Hz, 4H), 3.32 (t, J=6.4 Hz, 4H), 2.71-2.61 (m, 2H), 1.73-1.62 (m, 2H), 1.46-1.20 (m, 4H), 0.93 (td, J=6.7, 4.3 Hz, 3H).

Synthesis Example 18

[0228] ##STR00482##

[0229] Oil.

[0230] .sup.1H NMR (chloroform-d) δ 7.43-7.34 (m, 2H), 7.17 (dd, J=9.0, 7.1 Hz, 2H), 6.67 (d, J=2.1 Hz, 2H), 6.39 (t, J=2.2 Hz, 1H), 4.51 (pd, J=6.2, 4.5 Hz, 2H), 3.98 (t, J=13.7 Hz, 4H), 3.70 (qd, J=10.5, 5.0 Hz, 4H), 2.63-2.52 (m, 2H), 1.65-1.50 (m, 2H), 1.28 (app t, J=6.8 Hz, 10H), 0.88-0.79 (m, 3H).

Synthesis Example 19

[0231] ##STR00483##

[0232] Oil.

[0233] .sup.1H NMR (chloroform-d) δ 7.51-7.40 (m, 2H), 7.27 (d, J=8.0 Hz, 2H), 6.80 (d, J=2.1 Hz, 2H), 6.48 (t, J=2.3 Hz, 1H), 4.56 (p, J=4.8 Hz, 2H), 4.18-4.04 (m, 8H), 3.93-3.81 (m, 8H), 2.73-2.62 (m, 2H), 1.72-1.61 (m, 2H), 1.44-1.33 (m, 4H), 0.97-0.86 (m, 3H).

Synthesis Example 20

[0234] ##STR00484##

[0235] Oil

[0236] .sup.1H NMR (chloroform-d) δ 7.02 (d, J=8.3 Hz, 2H), 6.82-6.74 (m, 2H), 4.41 (p, J=4.9 Hz, 1H), 3.94 (h, J=12.9 Hz, 4H), 3.83-3.73 (m, 4H), 2.52-2.43 (m, 2H), 1.57-1.45 (m, 2H), 1.31-1.13 (m, 12H), 0.81 (t, J=6.8 Hz, 3H).

Synthesis Example 21

[0237] ##STR00485##

[0238] Melting point 92° C. (C 92 I).

Mixture Examples: Liquid-Crystal Media with Additives

[0239] The following additives are added to the liquid-crystal media:

TABLE-US-00008 Additive No. Structure of the additive 1 [00486] 2 [00487] 3 [00488] 4 [00489] 5 [00490]

Mixture Examples

[0240] The following alignment additives are used:

(prepared as described in EP 2918658 or analogously)

##STR00491## ##STR00492## ##STR00493##

[0241] The following polymerizable compound is used:

##STR00494##

[0242] The base mixtures (hosts) used are the following liquid-crystal media H1 to H10 (figures in % by weight).

[0243] H1: Nematic host mixture (Δε<0)

TABLE-US-00009 CPP-3-2 10.5%  Clearing point [° C.]: 74.5 CC-3-4 9.0% Δn (589 nm, 20° C.): 0.109 CC-3-5 9.0% Δε (1 kHz, 20° C.): −3.4 CCP-3-1 8.0% ε.sub.∥ (1 kHz, 20° C.): 3.7 CCY-3-O2 9.5% ε.sub.⊥ (1 kHz, 20° C.): 7 CCY-4-O2 5.5% K.sub.1 (20° C.) [pN]: 14 CPY-3-O2 5.5% K.sub.3 (20° C.) [pN]: 15.7 CY-3-O2  15% γ.sub.1 (20° C.) [mPa .Math. s]: 128 CY-5-O2 5.0% CP-3-O1 7.0% PY-3-O2  16%

[0244] H2: Nematic host mixture (Δε<0)

TABLE-US-00010 CPP-3-2 6% Clearing point [° C.]: 74.8 CC-3-V1 6% Δn (589 nm, 20° C.): 0.107 CC-3-4 9% Δε (1 kHz, 20° C.): −3.3 CC-3-5 7% ε.sub.∥ (1 kHz, 20° C.): 3.6 CCP-3-1 8% ε.sub.⊥ (1 kHz, 20° C.): 6.9 CCP-3-3 3% K.sub.1 (20° C.) [pN]: 14.2 CCY-3-1 2% K.sub.3 (20° C.) [pN]: 16.5 CCY-3-O2 10.5%   γ.sub.1 (20° C.) [mPa .Math. s]: 118 CCY-4-O2 5% CPY-3-O2 3.5%.sup.  CY-3-O2 14%  CP-3-O1 5.5%.sup.  PY-1-O4 6.5%.sup.  PY-3-O2 14%  CPP-3-2 6% CC-3-V1 6%

[0245] H3: Nematic host mixture (Δε<0)

TABLE-US-00011 B-2O-O5 4% Clearing point [° C.]: 74.2 CPP-3-2 8% Δn (589 nm, 20° C.): 0.109 CC-3-V1 9% Δε (1 kHz, 20° C.): −3.1 CC-3-O1 2% ε.sub.∥ (1 kHz, 20° C.): 3.6 CC-3-4 8% ε.sub.⊥ (1 kHz, 20° C.): 6.7 CC-3-5 7% K.sub.1 (20° C.) [pN]: 14.5 CCP-3-1 8% K.sub.3 (20° C.) [pN]: 16.5 CCP-V2-1 5% γ.sub.1 (20° C.) [mPa .Math. s]: 108 CCY-3-O2 10.5%   CLY-3-O2 1% CPY-3-O2 2.5%.sup.  CY-3-O2 11.5%   CP-3-O1 5.5%.sup.  PY-3-O2 18% 

[0246] H4: Nematic host mixture (Δε<0)

TABLE-US-00012 B(S)-2O-O5 4% Clearing point [° C.]: 74.7 CPP-3-2 5% Δn (589 nm, 20° C.): 0.102 CC-3-V1 6% Δε (1 kHz, 20° C.): −3.2 CC-3-4 9% ε.sub.∥ (1 kHz, 20° C.): 3.6 CC-3-5 9% ε.sub.⊥ (1 kHz, 20° C.): 6.7 CCP-3-1 8% K.sub.1 (20° C.) [pN]: 13.5 CCY-3-O1 6.5%.sup.  K.sub.3 (20° C.) [pN]: 16.5 CCY-3-O2 9% γ.sub.1 (20° C.) [mPa .Math. s]: 109 CLY-3-O2 1% CPY-3-O2 4.5%.sup.  CY-3-O2 13%  CP-3-O1 15%  PY-1-O2 8% PY-2-O2 2%

[0247] H5: Nematic host mixture (Δε<0)

TABLE-US-00013 CC-2-3 14% Clearing point [° C.]: 110.5 CC-3-4 12% Δn (589 nm, 20° C.): 0.102 CCP-3-1  3% Δε (1 kHz, 20° C.): −3.1 CCY-3-1  8% ε.sub.∥ (1 kHz, 20° C.): 3.2 CCY-3-O2 12% ε.sub.⊥ (1 kHz, 20° C.): 6.2 CCY-3-O3 12% K1 (20° C.) [pN]: 18.1 CCY-4-O2 10% K3 (20° C.) [pN]: 19.3 CPY-2-O2  3% γ1 (20° C.) [mPa .Math. s]: 190 CPY-3-O2 10% CP-3-O1 10% PYP-2-3  6%

[0248] H6: Nematic host mixture (Δε<0)

TABLE-US-00014 Host H1 98.85% RM-1 0.35%%

[0249] H7: Nematic host mixture (Δε<0)

TABLE-US-00015 Host H2 98.95% RM-1 0.25%

[0250] H8: Nematic host mixture (Δε<0)

TABLE-US-00016 Host H3 98.85% RM-1 0.35%

[0251] H9: Nematic host mixture (Δε<0)

TABLE-US-00017 Host H4 98.85% RM-1 0.35%

[0252] H10: Nematic host mixture (Δε<0)

TABLE-US-00018 Host H5  99% RM-1 0.2%

[0253] Various %-proportions by weight of the example additives and one or two alignment additives are added to the LC host mixtures, which are then investigated with respect to various parameters (alignment, drop mura, reliability).

[0254] For example, to these media H1 to H10 the spreading additives no. 1 to 5 are added in percentages of about 0.025 (±0.01) % by weight and one or more of the alignment additives II-A to II-K in an amount of about 0.5 (±0.3) % by weight.

Test Sample Results

[0255]

TABLE-US-00019 TABLE 1 Composition of Mixture Examples (additives in % by weight, the LC host mixture makes up the remaining percentage) Mixture Example 1 Mixture Example 2 Polymerizable 0.35% of RM-1 0.35% of RM-1 compound Self-alignment 0.6% of II-B 0.3% of II-B additive(s) for 0.2% of II-C vertical alignment Polyfluorinated 0.025% of 1 0.025% of 1 spreading additive LC host mixture H1 (adding to 100%) H1 (adding to 100%)

[0256] The procedure for test cell manufacture is,

1) adding polyfluorinated additive into SA-VA LC mixture,
2) dispensing LC mixture and sealant onto substrate,
3) cell assembly,
4) sealant curing,
5) PS-VA 1.sup.st and 2.sup.nd UV process,
6) Initial alignment confirmation and other evaluations.

[0257] To confirm the initial alignment, a DSLR camera (Nikon) for gathering high quality cell image is used.

[0258] The results of Example 1 are provided in FIG. 1. The initial alignment of the test cell is visibly improved in the edge regions.

[0259] The results of Example 2 are provided in FIG. 2. The initial alignment of the test cell is visibly improved in the edge regions.

[0260] In summary, the additives of formula I improved the initial alignment.

ODF Mura Evaluation

[0261] The ODF test enables evaluation of the additives under actual process conditions and shows whether ODF mura actually occurring can also be improved. The ODF test is composed of a number of part-processes.

a) Production of the Test Displays

[0262] The substrates are cleaned before further processing, with the aim of removing all adhering particles. This is carried out by machine in a multistep process in which rinsing is carried out stepwise with a soap solution (distilled water and 0.5% of detergent) and pure distilled water. After completion of the rinsing operation, the substrates are dried at 120° C. for 30 min. [0263] This is followed by application of the adhesive (Sekisui) at the edge of the substrate and the dropwise application (ODF) of the LC medium to the substrate. The lower substrate with the adhesive and the LC medium is brought together with an upper substrate provided with ITO and photospacer (3.3 μm) by means of vacuum (5 Pa, 30 s). This is followed by adhesion of the test display by means of UV light, with only the adhesive edge being exposed, and a heating step (in accordance with the adhesive manufacturer's instructions). [0264] This is then followed by the PS-VA process for achieving the pre-tilt. To this end, a direct voltage of about 10 V is applied to the cell with UV illumination. The UV illumination initiates photopolymerization of the RM. The desired tilt is established via the RM concentration, the illumination intensity, the illumination duration or the strength of the applied field. When the desired pre-tilt has been achieved, the process is terminated. This is followed by a second UV step without voltage in order to remove the remaining RM.

b) Evaluation of the Drop Mura

[0265] The ODF mura can be described by visual inspection and, alternatively, by measuring of tilt angles in different regions.

Tilt Measurements:

[0266] The pre-tilt set is measured by means of a Mueller matrix polarimeter (Axometrics Axostep) with spatial resolution in the region in which the drop was located before spreading out during the vacuum process, and in the region where no LC medium was located before the process. The difference is a criterion which describes the ODF level. The smaller the difference, the smaller the ODF mura occurring. [0267] The test display is operated at various grey shades (various driver voltages) against backlighting. With the aid of a DSLR camera, images of the display are recorded and analysed by means of software. The grey shades are determined with the aid of electro-optical curves (transmission against voltage) using an LCD-5200 (Otsuka, JP).

c) Results

[0268]

TABLE-US-00020 TABLE 2 ODF mura results Mixture Example 1 Mixture Example 2 ODF drop mura none none

[0269] The medium according to the invention showed no visible drop mura.

Mixture Examples 3 to 6

[0270]

TABLE-US-00021 TABLE 2 Composition of Mixture Examples (additives in % by weight, the LC host mixture makes up the remaining percentage) Mixture Example 3 Mixture Example 4 Polymerizable 0.30% of RM-1 0.30% of RM-1 compound Self-alignment 0.6% of II-B 0.3% of II-B additive(s) for 0.2% of II-C vertical alignment Polyfluorinated 0.025% of 1 0.025% of 1 spreading additive LC host mixture H1 (adding to 100%) H1 (adding to 100%)

TABLE-US-00022 TABLE 3 Composition of Mixture Examples (additives in % by weight, the LC host mixture makes up the remaining percentage) Mixture Example 5 Mixture Example 6 Polymerizable 0.30% of RM-1 0.30% of RM-1 compound Self-alignment 0.6% of II-B 0.3% of II-B additive(s) for 0.2% of II-C vertical alignment Polyfluorinated 0.025% of 1 0.025% of 1 spreading additive LC host mixture H2 (adding to 100%) H2 (adding to 100%)