Additives for liquid crystal mixtures

Abstract

Polyfluorinated additives for use as components in liquid-crystal mixtures. Liquid-crystal mixtures which comprise these compounds. And liquid-crystal displays based on these liquid-crystal mixtures.

Claims

1. Liquid-crystalline medium comprising a liquid-crystalline component and one or more polymerisable or polymerised compounds, wherein the liquid crystalline component comprises one or more compounds of the formula II ##STR00475## 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, ##STR00476## denotes ##STR00477## p and q each, independently of one another, denote 0, 1 or 2 and (p+q) denotes 1, 2 or 3, and wherein the liquid-crystalline medium comprises an additive of the following formula I: ##STR00478## in which R.sup.1 denotes a straight-chain alkyl group having 1 to 20 C atoms, a branched alkyl group having 3 to 20 C atoms or H, where, in addition, one or more CH.sub.2 groups in the alkyl groups may each be replaced, independently of one another, by —C≡C—, —CH═CH—, ##STR00479## —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 group selected from the following formulae: —R.sup.2 ##STR00480## where R.sup.2 in each case independently denotes ##STR00481## 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 or 3 to 10 C atoms if branched or cyclic, in which one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S—, 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, n denotes 0, 1, 2, 3 or 4.

2. Liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds of the formula IV, ##STR00482## 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.

3. Liquid-crystalline medium according to claim 1, wherein the total concentration of the additive of the formula I in the entire medium is 0.001% by weight or more to 2% by weight or less.

4. A compound of the formula I ##STR00483## in which R.sup.1 denotes a straight-chain alkyl group having 1 to 20 C atoms, a branched alkyl group having 3 to 20 C atoms or H, where, in addition, one or more CH.sub.2 groups in the alkyl groups may each be replaced, independently of one another, by —C≡C—, —CH═CH—, ##STR00484## —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 group selected from the formulae ##STR00485## R.sup.2 in each case independently denotes a group of the following formula: ##STR00486## wherein Rf.sup.1, Rf.sup.3 independently denote —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 or 3 to 10 C atoms if branched or cyclic, in which one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S—, Z.sup.1 in each case 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.2 denotes a linear or branched trivalent spacer, A.sup.1 in each case independently denotes a cyclohexane ring or benzene ring, which is optionally additionally substituted by one or two groups 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.

5. A compound according to claim 4, wherein: R.sup.F denotes a group selected from the formulae ##STR00487## n denotes 0, 1 or 2.

6. A compound according to claim 4, selected from the group of the compounds of the formulae IA to IF: ##STR00488## in which the variables independently have the meaning given in claim 4.

7. A compound according to claim 4, which is selected from the group of the compounds of the formulae I-1 to 1-4, ##STR00489## in which the variables independently have the meaning given in claim 4.

8. Process for the preparation of a compound according to claim 6, comprising etherifying a compound of the formula I in which R.sup.2 in each case independently denotes ##STR00490## in the presence of a fluorinated alcohol of the formula ##STR00491## where the formula I and the substituents are defined as in claim 4.

9. Electro-optical display containing a liquid-crystal medium according to claim 1.

10. Process which comprises filling an electro-optical display with a liquid-crystal medium, wherein the liquid-crystal medium comprises an additive of the formula I according to claim 1.

11. A method for preparing a liquid-crystal medium according to claim 1, which comprises adding a compound of formula I to one or more other liquid-crystal compounds.

Description

EXAMPLES

(1) 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).

(2) 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.

(3) 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

(4) ##STR00446## ##STR00447##

(5) 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).

(6) 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).

(7) 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

(8) ##STR00448## ##STR00449##

(9) 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).

(10) 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).

(11) 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).

(12) 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.).

(13) The following are prepared analogously to Example 1 or 2:

Synthesis Example 3

(14) ##STR00450##

(15) Melting point 65° C. (C 65 I).

Synthesis Example 4

(16) ##STR00451##

Synthesis Example 5

(17) ##STR00452##

(18) Melting point 40° C. (C 40 SmA (23) I)

Synthesis Example 6

(19) ##STR00453##

(20) Melting point 36° C. (C 36 I)

Synthesis Example 7

(21) ##STR00454##

(22) 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

(23) ##STR00455##

(24) Oil (Tg −19° C. I)

Synthesis Example 9

(25) ##STR00456##

Synthesis Example 10

(26) ##STR00457##

Synthesis Example 11

(27) ##STR00458##

Synthesis Example 12

(28) ##STR00459##

Synthesis Example 13

(29) ##STR00460##

Synthesis Example 14

(30) ##STR00461##

(31) Oil.

(32) .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

(33) ##STR00462##

Synthesis Example 16

(34) ##STR00463##

Synthesis Example 17

(35) ##STR00464##

(36) Oil.

(37) .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

(38) ##STR00465##

(39) Oil.

(40) .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

(41) ##STR00466##

(42) Oil.

(43) .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

(44) ##STR00467##

(45) Oil

(46) .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

(47) ##STR00468##

(48) Melting point 92° C. (C 92 I).

(49) Use examples: Liquid-crystal mixtures with additive

(50) The following additives are added to the liquid-crystal media:

(51) TABLE-US-00008 Additive No. Structure of the additive 1 2 0 3 4 5

(52) The following polymerisable compound is used:

(53) ##STR00474##

(54) The base mixtures (hosts) used are the following liquid-crystal media H1 to H15 (figures in % by weight).

(55) TABLE-US-00009 H1: Nematic host mixture (Δε < 0) CC-3-V  15% CC-3-V1 9.0% CC-2-3 8.0% CC-3-4 7.5% CCY-3-O2  10% CCY-5-O2 8.0% CPY-2-O2 3.0% CPY-3-O2 8.5% CY-3-O2 7.0% PY-3-O2  16% PYP-2-3   8% H2: Nematic host mixture (Δε < 0) CC-3-V1   8% CC-2-3  18% CC-3-4   4% CC-3-5   7% CCP-3-1   5% CCY-3-O2 12.5%  CPY-2-O2   8% CPY-3-O2  11% CY-3-O2 15.5%  PY-3-O2  11% H3: Nematic host mixture (Δε < 0) CPP-3-2 5.5% CCP-3-1 8.0% CCY-3-O1 10% CCY-3-O2 8.5% CPY-3-O2  11% CC-3-V1 9.0% CC-3-O1 6.0% CY-3-O2  11% CP-3-O1  20% PY-3-O2  11% H4: Nematic host mixture (Δε < 0) CC-3-V 36.5%  CC-3-V1 2.0% CCY-3-O1 8.0% CCY-3-O2 6.0% CCY-4-O2 2.5% CLY-3-O2 8.0% CLY-3-O3 2.0% CPY-2-O2  10% CPY-3-O2 3.0% CY-3-O2 5.5% PY-3-O2  13% PY-1-O4 3.5% H5: Nematic host mixture (Δε < 0) B-2-O-O5 4.0% CPP-3-2 8.0% CC-3-V1 9.0% CC-3-O1 2.0% CC-3-4 8.0% CC-3-5 7.0% CCP-3-1 8.0% CCP-V2-1 5.0% CCY-3-O2 10.5%  CLY-3-O2 1.0% CPY-3-O2 2.5% CY-3-O2 11.5%  CP-3-O1 5.5% PY-3-O2  18% H6: Nematic host mixture (Δε < 0) B(S)-20-O5 4.0% B(S)-20-O4 3.0% CPP-3-2 8.0% CC-3-V1 9.0% CC-3-O1 2.0% CC-3-4 8.0% CC-3-5 7.0% CCP-3-1  11% CCP-V2-1 5.0% CCY-3-O2 7.0% CLY-3-O2 1.0% CY-3-O2  13% CP-3-O1 5.5% PY-3-O2 16.5%  H7: Nematic host mixture (Δε > 0) APUQU-2-F 2.0% APUQU-3-F 5.0% CPU-2-F 5.0% CPU-3-F  10% CPPC-3-3 4.0% CC-3-V1 6.0% CC-5-V 8.0% CC-3-4 8.0% CCGU-3-F 9.0% CCP-3-OCF3 9.0% CCP-3-1 4.0% CCZPC-3-3 3.5% CP-3-O1  10% PGUQU-3-F 4.0% PPGU-3-F 1.0% PUQU-3-F 11.5%  H8: Nematic host mixture (Δε < 0) B-2-O-O5 4.0% CPP-3-2 8.0% CC-3-V1 9.0% CC-3-O1 2.0% CC-3-4 8.0% CC-3-5 7.0% CCP-3-1 8.0% CCP-V2-1 5.0% CCY-3-O2 10.5%  CLY-3-O2 1.0% CPY-3-O2 2.5% CY-3-O2 11.5%  CP-3-O1 5.5% PY-3-O2  18% H9: Nematic host mixture (Δε > 0) APUQU-2-F 6.0% APUQU-3-F 8.0% CDUQU-3-F  10% DGUQU-4-F 4.0% DPGU-4-F 5.0% PGUQU-3-F 3.0% PGUQU-4-F 7.0% CCQU-3-F 9.0% CC-3-2V1  10% CC-3-V 24.5%  CC-3-V1 9.5% CCP-3-OCF3 4.0% H10: Nematic host mixture (Δε > 0) CC-3-V  32% CC-3-V1  11% CC-3-2V1 4.5% PP-1-2V1 2.0% CCP-3-OCF3 7.5% CCP-5-OCF3 1.5% PUQU-3-F 1.5% APUQU-2-F 7.0% APUQU-3-F 7.0% PGUQU-3-F 3.0% PGUQU-4-F 8.0% PGUQU-5-F 2.0% DPGU-4-F 5.0% DGUQU-4-F 8.0% H11: Nematic host mixture (Δε > 0) CC-3-V  42% CC-3-V1 5.5% CCP-V-1 4.0% CCP-3-OCF3 7.0% PGP-2-2V 6.5% APUQU-2-F 3.0% APUQU-3-F 8.0% PGUQU-3-F 4.0% CPGU-3-OT 5.0% CPY-3-O2 3.0% CY-3-O2 9.0% PYP-2-3 3.0% H12: Nematic host mixture (Δε > 0) CC-3-V  48% CC-3-V1 10.5%  CCP-V-1  11% CLP-V-1 6.0% CLP-3-T 5.5% PGP-2-2V 5.0% PGUQU-3-F 4.0% APUQU-2-F 4.5% PP-1-2V1 5.0% PPGU-3-F 0.5% H13: Nematic host mixture (Δε > 0) CCQU-2-F  15% CCQU-3-F  15% CCQU-5-F  15% CCU-3-F  12% CCU-5-F 6.0% CCP-3-1  10% CGPC-5-3 6.0% CGPC-3-3 3.0% CDUQU-3-F 8.0% CCP-2-OCF3 5.0% CCP-3-OCF3 5.0% H14: Nematic host mixture (Δε < 0) Host H1 99.55%  RM-1 0.45%  H15: Nematic host mixture (Δε > 0) CC-3-V  48% CC-3-V1  12% CCP-V-1 11.5%  CLP-V-1 9.0% PGP-2-2V 4.5% PGUQU-3-F 3.0% APUQU-2-F 7.5% PP-1-2V1 4.0% PPGU-3-F 0.5%

(56) Various % proportions by weight of the example additives indicated are added to the base mixture, which is then investigated with respect to various parameters (contact angle, surface tension, droplet size, ODF drop mura).

(57) 1. Measurement of the Contact Angle

(58) The contact angle between the substrate surface and the liquid-crystal medium is investigated using a Krüss “Easy Drop” drop shape analyser. The substrate is coated with a polyimide (product JALS-2347-R6 from JSR, Table 1) or with ITO. The measurement is carried out using a drop having a volume of 0.4 μl at room temperature (21° C.) and 45% relative atmospheric humidity. To this end, a single drop is applied using a metering pipette and measured photographically after a waiting time of 60 s. The contour is analysed by means of the circle method.

(59) The measurement results are shown in Tables 1 and 2 below.

(60) TABLE-US-00010 TABLE 1 Contact angle measurement values of the test mixtures with various additives and variation of the added amount on polyimide-coated substrates. Measurement after 60 s. Base Contact angle Standard No. Additive (% by wt.) mixture [ °] deviation [ °] 1 none (0% by wt.) H3 19.2 0.7 2 1 (0.037% by wt.) H3 18.1 1.3 3 1 (0.37% by wt.) H3 11.2 0.4 4 1 (1.2% by wt.) H3 10.1 0.5 5 2 (0.010% by wt.) H3 14.0 0.4 6 2 (0.23% by wt.) H3 12.3 0.3 7 2 (0.03% by wt.) H3 13.9 0.7 8 2 (0.1% by wt.) H3 16.1 0.3 9 2 (0.22% by wt.) H3 17.0 0.5 10 — H2 14.0 0.6 11 1 (0.13% by wt.) H2 14.2 0.8 12 1 (0.30% by wt.) H2 13.0 0.3 13 1 (1.30% by wt.) H2 11.3 0.2 14 — H1 13.8 0.3 15 1 (0.30% by wt.) H1 11.6 0.4 16 2 (0.023% by wt.) H1 9.4 0.4 17 — H4 15.2 0.1 18 2 (0.023% by wt.) H4 13.0 0.2 19 3 (1% by wt.) H4 12.5 0.1 20 — H5 16.5 0.9 21 2 (0.023% by wt.) H5 14.0 0.8 22 3 (1% by wt.) H5 13.0 0.4 23 — H6 17.9 0.3 24 2 (0.023% by wt.) H6 13.1 0.6 25 3 (1% by wt.) H6 14.6 0.2 26 — H7 16.2 0.1 27 2 (0.023% by wt.) H7 13.2 0.2 28 3 (1% by wt.) H7 13.9 0.2 29 — H8 18.7 0.5 30 2 (0.023% by wt.) H8 13.6 0.1 31 3 (1% by wt.) H8 14.8 0.5 32 — H9 15.7 0.5 33 2 (0.023% by wt.) H9 15.3 0.5 34 3 (1% by wt.) H9 14.1 0.2 35 — H10 12.9 0.2 36 2 (0.023% by wt.) H10 12.0 0.5 37 3 (1% by wt.) H10 11.6 0.1 38 — H11 11.0 0.8 39 2 (0.023% by wt.) H11 10.2 0.4 40 3 (1% by wt.) H11 9.9 0.4 41 — H12 14.5 0.4 42 3 (1% by wt.) H12 11.1 0.4 43 — H13 14.5 0.4 44 3 (1% by wt.) H13 11.3 0.3 45 — H14 14.8 0.7 46 3 (1% by wt.) H14 11.6 0.4

(61) TABLE-US-00011 TABLE 2 Contact angle measurement values of the test mixtures with various additives in base mixture H14 and variation of the added amount on various substrates (ITO, glass and PSA-PI CT 16557). Measurement after 20 s. Substrate Contact Standard No. Additive % by wt. surface angle [ °] deviation [ °] 1 — — PSA-PI 13.1 0.5 2 2 0.025 PSA-PI 11.9 0.2 3 3 1 PSA-PI 11.4 0.4 4 2 + 3 0.025 + 1 PSA-PI 10.8 0.2 5 — — ITO 5.8 1.6 6 2 0.025 ITO 4.3 0.9 7 3 1 ITO 5.2 0.9 8 2 + 3 0.025 + 1 ITO 5.1 0.8 9 — — Glass 19.5 0.3 10 2 0.025 Glass 6.2 0.2 15 5 0.01 Glass 11.9 2.1 16 5 0.025 Glass 10.4 2.0 17 5 0.1 Glass 10.4 1.4 18 5 1 Glass 11.1 0.34

(62) The contact angles are already reduced significantly by a small amount (<1%) of additives. A small contact angle improves the spreading behaviour.

(63) 2. Measurement of the Surface Tension

(64) The surface tension of the liquid-crystal media is investigated using a Krüss “Easy Drop” drop shape analyser. The measurement method used measures the deformation of a hanging drop under the action of gravity. The measurement is carried out using a dropping tip with a diameter of 1.054 mm at room temperature (21° C.) and 45% relative atmospheric humidity. The needle tip and the drop are recorded using a camera and subsequently evaluated by means of the Young-Laplace equation. The specific density of the liquid-crystal media is measured using a flexural resonator. The measurement results are shown in Table 3 below.

(65) TABLE-US-00012 TABLE 3 Surface tension measurement values of the test mixtures with various additives and variation of the added amount. Surface Standard Base tension deviation No. Additive (% by wt.) mixture [mN/m] [mN/m] 1 none (0% by wt.) H2 28.10 0.04 2 1 (1.5% by wt.) H2 24.58 0.06

(66) The result obtained is a clear reduction in the surface tension due to the addition of an additive to a liquid-crystal mixture.

(67) 3. Measurement: Enlargement of the Drop Size After Application

(68) The analysis of the drop size is carried out using a microscope and an evaluation program for determination of the geometrical surface of a drop on the substrate. For the measurement, in each case a drop having a volume of 10.0 μl is applied to the substrate. After prespecified waiting times (0.25 min, 5 min, 60 min), the wetted surface is photographed and evaluated. For each waiting time, the relative drop size compared with a medium without additive (reference waiting time 0.25 min or 5 min) is determined. The measurement results on polyimide (on glass), glass, and Ito (on glass) substrates are shown in the Tables 4, 5 and 6 below.

(69) TABLE-US-00013 TABLE 4 Relative drop size after waiting time with various additives on polyimide (reference waiting time = 0.25 min). Relative drop size after Base waiting time, [%] No. Additive (% by wt.) mixture 0.25 min 5 min 60 min 1 none (0% by wt.) H2 100 106 109 2 1 (1.5% by wt.) H2 118 135 149 3 none (0% by wt.) H1 100 102 101 4 1 (1.5% by wt.) H1 108 125 141

(70) TABLE-US-00014 TABLE 5 Relative drop size after waiting time with various additives on glass (reference waiting time = 5 min). Relative drop size after Base waiting time, [%] No. Additive (% by wt.) mixture 5 min 1 none (0% by wt.) H2 100 2 1 (1.5% by wt.) H2 330 3 none (0% by wt.) H1 100 4 1 (1.5% by wt.) H1 442

(71) TABLE-US-00015 TABLE 6 Relative drop size after waiting time with various additives on ITO (reference waiting time = 5 min). Relative drop size after Base waiting time, [%] No. Additive (% by wt.) mixture 5 min 1 none (0% by wt.) H14 100 2 2 (0.025% by wt.) H14 210 3 4 (1% by wt.) H14 155 4 2 (0.025% by wt.) + H14 225 4 (1% by wt.)

(72) The advantageous enlargement of the droplet size on a substrate, i.e. analogous to ODF conditions, indicates good flow behaviour, readiness for spreading and for even distribution, and rapid homogeneous distribution of the liquid-crystal media. This facilitates a short cycle time in the filling process and fewer droplet traces (ODF mura).

(73) 4. ODF Test

(74) The ODF test enables evaluation of the additives under actual process conditions and shows whether ODF mura actually occurring can also be improved by the improved spreading behaviour. The ODF test is composed of a number of part-processes.

(75) a) Production of the Test Displays 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. The polyimide is applied to an ITO-coated glass substrate from solution (N-methyl-2-pyrrolidone and Butylcellosolve) by means of spin coating (MIKASA). To this end, a drop of the polyimide solution is applied to the substrate and spun firstly at 80 rpm for 10 s and then at 760 rpm for 45 s. After the process, the PI should have a homogeneous layer thickness of 100 nm. The substrate is then dried at 60° C. on a hotplate for 1 min and then at 230° C. in an oven for 90 min. If necessary, the polyimide is pre-aligned. 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). This is then followed by the PS-VA process for achieving the pre-tilt.

(76) To this end, a direct voltage of about 10 V is applied to the cell with UV illumination. The UV illumination initiates photopolymerisation 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.

(77) b) Evaluation of the Drop Mura 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. 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).

(78) c) Results

(79) Table 7 shows the results of the pre-tilt measurements in the former drop region and non-drop region. The difference in pre-tilt between these two regions is significantly reduced in the presence of the additives, which confirms the efficacy of the additives in an ODF process. The results of the image analysis in Table x are in agreement with these results. A lower drop mura level arises for the mixtures with additive compared with the mixture without additive. The best action is achieved with additive 2.

(80) TABLE-US-00016 TABLE 7 Pre-tilt in the drop and non-drop region and the difference thereof. The smaller the difference, the less pronounced is the drop mura. Base Pre-tilt, [°] No. Additive (% by wt.) mixture Non-drop Drop Difference 1 none (0% by wt.) H14 86.40 85.12 1.28 2 2 (0.025% by wt.) H14 86.38 85.77 0.61 3 3 (1% by wt.) H14 86.42 85.75 0.67

(81) The image analysis for a defined grey shade shows the same trend. The contrast between the area on which the drop was lying and free area is also smaller here in the case of addition of additives.

(82) TABLE-US-00017 TABLE 8 Drop mura level for a grey shade of L-16 after image analysis by means of software. Base Drop mura No. Additive (% by wt.) mixture level 1 none (0% by wt.) H14 131%  2 2 (0.025% by wt.) H14 51% 3 3 (1% by wt.) H14 61%