Ferroelectric nematic liquid crystal medium

Abstract

The new LC media exhibit a ferroelectric nematic phase at ambient temperature. They contain at least one compound represented by formula IA having at least 5 rings, wherein the variable groups have the meanings indicated in the text and in the claims. The mixtures are useful for electro-optical, electronic, electromechanical, and other applications for materials with very high dielectric constants.

Description

Technical Field

[0001] Aspects of the present invention relate to liquid crystal media that exhibit a ferroelectric nematic liquid crystal phase over a substantial range of temperatures, preferably at ambient temperature. The media typically contain one or more compounds represented by formula IA and optionally IB and IC as defined below. In addition, the present invention relates to liquid crystal devices (e.g., displays), electric and electronic elements containing a liquid crystal medium according to the present invention.

Background Art

[0002] In recent years, the areas of application of liquid crystal compounds have been significantly expanded to various types of display devices, electro-optical devices, electronic components, sensors, etc. For this reason, numerous different structures have been proposed, especially in the field of nematic liquid crystals. Nematic liquid crystal mixtures have found the widest use to date in flat panel display devices. They are employed, in particular, in passive TN or STN matrix displays or systems with TFT active matrices, including the well-known TN, IPS, FFS, and VA systems.

[0003] Most of these devices, including all common LCD television receivers, LCD desktop monitors, and mobile LCD devices, employ a nematic liquid crystal phase. Some alternative liquid crystal phases are known, such as the ferroelectric smectic phase or the blue phase. However, the ferroelectric nematic phase (N f -LC phase) has only been hypothesized theoretically for decades, and no suitable liquid crystal materials with such properties have been found. Only very recently, a few chemical structures showing ferroelectric nematic behavior have been reported.

[0004] First of all, Hiroya Nishikawa, Kazuya Shiroshita, Hiroki Higuchi, Yasushi Okumura, Yasuhiro Haseba, Shin-ichi Yamamoto, Koki Sago, and Hirotsugu Kikuchi, Adv. Mater. (2017), 29, 1702354 describes a compound represented by Formula A having ferroelectric nematic behavior at a temperature between about 45 °C and 68 °C. [Chemical formula]

[0005] Furthermore, Nerea Sebastian, Luka Cmok, Richard J. Mandle, Maria Rosario de la Fuente, Irena Drevensek Olenik, Martin Copic and Alenka Mertelj, Physical Review Letters (2020), 124, 037801 describes a compound represented by Formula B having similar behavior between about 120 °C and 133 °C. [Chemical formula]

[0006] N f A further comparison of the only two substances available for the N-LC phase is presented by Xi Chen et al., PNAS (June 23, 2020), 117(25)14021 - 14031. The new N f The high importance of the advent of the -LC phase is clearly shown by O.D. Lavrentovich, Proc Nat Acad Sci USA (2020), 117(26), 14629 - 14631.

[0007] The extremely high values of the dielectric susceptibility of these substances and some structural variations thereof are reported in the publication Li et al., Sci. Adv. 2021, 7.

[0008] The new ferroelectric nematic substance represented by formula C was published by Atsutaka Manabe, Matthias Bremer, Martin Kraska (2021): Ferroelectric phase at and below room temperature, Liquid Crystals, 48, 1079 - 1086 (DOI 10.1080 / 02678292.2021.1921867), which describes having a ferroelectric nematic liquid crystal phase (N f -LC phase) near ambient temperature. Ambient temperature, sometimes also called room temperature, here in the narrow sense means a temperature of 20 °C. [Chemical formula]

[0009] C Y. Song et al. (Phys.Chem.Chem.Phys., 2022, DOI: 10.1039 / d2cp01110g) describe a substance having a ferroelectric nematic phase at high temperature, which has the following structure D: [Chemical formula]

[0010] N f The effective utilization of the N-LC phase for technical applications would be a clear benefit due to its applicability to ambient temperature. Technical devices and electronic applications are generally designed to have operating ranges above and below ambient temperature (room temperature), for example, from 15 °C to 25 °C, preferably from 0 °C to 50 °C, and more preferably an even wider operating range.

[0011] A ferroelectric nematic display was proposed in DE19629551 A1, but it does not disclose any specific materials that could meet the required ferroelectric nematic properties.

[0012] The use of fluorinated liquid crystal substances is known to those skilled in the art. Various compounds containing two 2,6-difluorinated 1,4-phenylene rings have already been described as liquid crystal materials or mesogenic materials, for example, in publication WO 2015 / 101405 A1 and various other publications (and various more). The compounds proposed therein have three to four aromatic rings and are characterized as conventional nematic materials without ferroelectric nematic properties.

[0013] An object of the present invention was to find novel stable compounds that are suitable as components (singular or plural) of a ferroelectric nematic liquid crystal medium (N f -LC phase medium). In particular, the compounds should simultaneously have an N f -LC phase or should support such a phase in an N f -LC medium. They should also have a medium to high optical anisotropy in order to realize an electrooptical switching effect in the same way as in conventional nematic LC media.

[0014] Considering the extremely diverse fields of application of this type of compound having a high dielectric anisotropy (Δε), it was desired to have further available compounds, preferably those having a high clearing point and a low melting point while showing a broad and suitable temperature range of the ferroelectric nematic phase.

[0015] Thus, it was a further object of the present invention to find novel stable compounds that are suitable as components (singular or plural) of such a ferroelectric nematic liquid crystal medium, especially for displays similar to conventional nematic TN, STN, IPS, FFS, and TN-TFT displays.

[0016] In addition, it was also an aim that the compounds be thermally and photochemically stable under the conditions prevailing in the fields of application. They should promote a wide ferroelectric nematic phase as mesogens, especially at low temperatures, at temperatures below at least room temperature.

[0017] Surprisingly, a medium containing certain selected compounds as described below can achieve a ferroelectric phase in a very advantageous temperature range, and when certain new compounds are combined with conventional compounds, N f -LC media have been found to be particularly suitable as components. They are not limited to liquid crystal media for devices requiring, inter alia, a particularly high or even extremely high dielectric anisotropy, especially for IPS or FFS displays, but also include liquid crystal media for other devices for electronic applications, capacitors and electromechanical devices that utilize materials with a high dielectric constant, and can be used to obtain LC media with unprecedented properties. The media and compounds used according to the invention are sufficiently stable and colorless. In particular, they are distinguished by extremely high dielectric constants, especially by an extremely high dielectric anisotropy (Δε), which results in a low threshold voltage being required when used in optical switching elements. The present compounds have moderately good solubility as compounds with equivalent properties and can be mixed almost unrestrictedly with similar compounds. In addition, the compounds used according to the invention have a high clearing point. These compounds also have a relatively low melting point or can be stably maintained as a supercooled melt below their melting point. The present invention enables the formation of the desired N f -LC phase below room temperature.

[0018] High dielectric permeability would enable outstanding physical properties. High (relative) dielectric permittivity is also particularly advantageous for the dielectrics in capacitors, as it causes a high capacitance on a given electrode area. In addition, the present media have extremely low electrical conductivity and, due to their fluidity, are more unique than conventional high-ε r materials (for example, barium titanate).

[0019] The liquid crystal medium can be used in displays based on the principle of the twisted cell, the guest-host effect, the deformation effect DAP or ECB (electrically controlled birefringence), the IPS (in-plane switching) effect, or the effect of dynamic scattering.

[0020] The present invention thus relates, in a main aspect, to a liquid crystal medium containing one or more compounds represented by formula IA, preferably containing at least 15% by weight of the following [Chemical formula] wherein X 1A represents -CN, F, or -NCS, preferably -CN, Z 1A and Z 2A are, independently of one another, -(CO)-O- or -CF2-O- or a single bond, L 1A is H or CH3, L 2A is independently F or H, preferably H, L 3A is independently F or H, preferably F, L 4A is independently F or H,

[0021] A 1A is [Chemical formula] is displayed, R 1A is, independently, an alkyl radical having from 1 to 12 C atoms, preferably from 1 to 8, more preferably from 1 to 6, and most preferably from 1 to 5 C atoms, where in addition, one or more CH2 groups in these radicals are, each time and independently of one another, -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, so that O atoms are not directly linked to one another, [Chemical formula] -O-, -S-, -(CO)-O-, or -O-(CO)- may be replaced, and where in addition, one or more H atoms may be replaced by halogen or represent H, preferably R 1A is a halogenated alkyl radical or an unsubstituted alkyl radical having from 1 to 10 C atoms, where in addition, one or more CH2 groups in these radicals may be replaced by -O- or -CH=CH- so that O atoms are not directly linked, n1 is 0 or 1, preferably 1, n2 is 0 or 1, and n3 is 2 or 3, while if n1 + n2 + n3 = 2, one or more of A 1A are [Chemical formula] is.

[0022] This means that if both n1 and n2 are 0, then at least one of A 1A is [Chemical formula] is.

[0023] The liquid crystal medium preferably additionally contains one or more compounds selected from the compounds represented by formulae IB and IC, [Chemical formula] In the formula X 1B represents -CN, F, or -NCS, preferably -CN, X 1C represents -CN, F, CF3, -OCF3, -NCS, SF5, or O-CF=CF2, preferably -CN or -NCS, most preferably CN, Z 1A and Z 2A each independently represent a single bond, -(CO)-O-, or -CF2-O-, preferably a single bond, Z 1C and Z 2C one of the two groups represents -(CO)-O- or -CF2-O-, and the other represents a single bond, preferably Z 1C is -(CO)-O- or -CF2-O-, and Z 2C is a single bond, L 1B each independently represents H or CH3, preferably H,

[0024] A 1A represents

Chemical formula

Chemical formula

[0025] A 1C each independently represents

Chemical formula

Chemical formula

[0026] A 2C is [Chem.] is displayed, preferably [Chem.] is displayed,

[0027] A 3C is [Chem.] is displayed, preferably [Chem.] is displayed, and R 1B and R 1C are, independently of one another, alkyl radicals having 1 to 12 C atoms, preferably 1 to 8, more preferably 1 to 6, and most preferably 1 to 5 C atoms, where in addition, one or more CH2 groups in these radicals are, each time, independently of one another, -C≡C-, -CF2-O-, -OCF2-, -CH=CH-, [Chem.] -O-, -S-, -(CO)-O-, or -O-(CO)- may be replaced, and where in addition, one or more H atoms may be replaced by halogen or represent H, preferably R 1A R 1B and R 1Cis, independently, a halogenated alkyl radical or an unsubstituted alkyl radical having 1 to 10 carbon atoms, where in addition, one or more CH2 groups in these radicals may be replaced by -O- or -CH=CH- such that an O atom is not directly linked.

[0028] The medium comprises: - preferably, a compound represented by formula IB in an amount of 15% by weight or more, and / or - preferably 15% by weight, preferably 20% by weight or more, of one or more compounds represented by formula IC, preferably said formula IC is selected from formulae IC-1 to IC-3 as described below.

[0029] The percentages are provided under the circumstance that the total medium constitutes 100% by weight of the medium.

[0030] The radicals R in each of formulae IA, IB, and IC, and their respective sub-formulae 1A , R 1B , and R 1C preferably represent alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, or alkenyl having 2 to 8 carbon atoms. These alkyl chains are preferably linear or, in the case of R 1C , are branched by a single methyl or ethyl substituent, preferably at the 2- or 3-position. R 1A , R 1B , and R 1C very particularly preferably represent a linear alkyl radical having 1 to 7 carbon atoms or an unbranched alkenyl radical having 2 to 8 carbon atoms, especially an unbranched alkyl having 1 to 5 carbon atoms.

[0031] Alternative preferred radicals R 1A , R 1B , and R 1Cis selected from cyclopentyl, 2-fluoroethyl, cyclopropylmethyl, cyclopentylmethyl, cyclopentylmethoxy, cyclobutylmethyl, 2-methylcyclopropyl, 2-methylcyclobutyl, 2-methylbutyl, 2-ethylpentyl, and 2-alkyloxyethoxy.

[0032] Branched or substituted terminal group R 1A , R 1B , and R 1C Compounds represented by formulae IA, IB, and IC1 - IC-3 containing 1A , R 1B , and R 1C are each sometimes important due to their better solubility in the liquid crystal base material. The groups R

[0033] Radicals R 1A , R 1B , and R 1C are each particularly preferably selected from the following moieties:

Chemical formula

[0034] Here, the following abbreviations are used for the terminal groups:

Chemical formula

[0035] A further aspect of the present invention is directed to a ferroelectric nematic liquid crystal medium comprising one or more compounds selected from formula IA as defined above and one or more from formulae IB and IC.

[0036] In a preferred embodiment, the present invention is directed to a ferroelectric nematic liquid crystal medium comprising one or more compounds selected from formulae IC-1 to IC-3 as defined below, preferably in the percentages and preferred formulae provided throughout this disclosure:

Chemical formula

[0037] In a preferred embodiment, the medium according to the present invention preferably contains one, two, three, or more compounds represented by formula IA-1,

Chemical formula

[0038] preferably selected from the group of formulas IA-1 to IA-3, preferably formulas IA-1-1, IA-2-1, and IA-3-1:

Chemical formula

Chemical formula

Chemical formula

[0039] For sub-formula IA-1, L 2A is preferably F, and L 3A , L 4A are preferably H. For sub-formula IA-2, L 2A is preferably H, and L 3A , L 4A are preferably F. Z 2A is preferably a single bond or -CF2O-, more preferably a single bond.

[0040] In a preferred embodiment, the medium according to the invention preferably comprises one, two, three or more compounds represented by formula IB-1 and / or IB-2 and / or IB-3, preferably represented by formula IB-1,

Chemical formula

Chemical formula

Chemical formula

[0041] A 1B is

Chemical formula

Chemical formula

[0042] Z 1B 、Z 2Bindependently represents -(CO)-O- or -CF2-O-, preferably selected from the group of the following formulas, formulas IB-1-1 to IB-3-1:

Chemical formula

Chemical formula

[0043] In a preferred embodiment, the medium according to the invention preferably contains one, two, three, or more compounds selected from those represented by formulas IC-1-1 to IC-3-6:

Chemical formula

Chemical formula

[0044] preferably selected from the group of the following formulas IC-1-1-1 to IC-3-5-2, preferably selected from the group of formulas IC-1-1-1, IC-1-1-2, IC-1-1-3, IC-1-1-4, IC-3-1-1, and IC-3-2-1:

Chemical formula

Chemical formula

Chemical formula

[0045] Particularly preferred compounds represented by formulas IC-1-1 to IC-1-4 used in the medium are compounds represented by the following formula:

Chemical formula

[0046] In addition to the compounds represented by formulas IA, IB, and IC-1 / -2 / -3, the medium according to the present invention optionally, preferably essentially, contains one, two, three, or more compounds selected from formulas ID-1 to ID-4.

Chemical formula

Chemical formula

[0047] A 1D represents a single bond

Chemical formula

Chemical formula

[0048] preferably it comprises one or more of Formulas ID-1-1 to ID-3-1: [Chemical Formula] wherein the variable group R 1D and L 8D are defined as above.

[0049] The medium optionally contains one or more compounds selected from the following group of compounds: Compounds represented by Formulas IA, IB, IC, and ID represent "Group 1" of the compounds.

[0050] In a preferred embodiment of the present invention, the medium contains up to 100% of one or more compounds, preferably 3, 4, 5, 6, or more compounds selected from Group 1 of the compounds. In this embodiment, the medium preferably consists mainly of these compounds, more preferably the medium consists essentially of these compounds, and most preferably the medium consists virtually entirely of these compounds.

[0051] For the present invention, the following definitions apply in relation to the identification of the constituent substances of the composition, unless otherwise indicated in individual cases. - "comprises": The concentration of the constituent substance in question in the composition is preferably 5% or more, particularly preferably 10% or more, and most particularly preferably 20% or more. - "consists mainly of": The concentration of the constituent substance in question in the composition is preferably 50% or more, particularly preferably 55% or more, and most particularly preferably 60% or more. - "Consisting essentially of": The concentration of the constituent substance in question in the composition is preferably 80% or more, more preferably 90% or more, and most preferably 95% or more, and - "Consisting substantially entirely of": The concentration of the constituent substance in question in the composition is preferably 98% or more, more preferably 99% or more, and most preferably 100.0%.

[0052] Preferably, the medium according to the present application satisfies one or more of the following conditions. They preferably include: - A compound represented by formula IA at 15% by weight or more, more preferably 20% by weight, more preferably 25%, 30%, 35, 45, or 50% by weight or more, - A compound represented by formula IB at 5% by weight or more, more preferably 10% by weight or more, more preferably 20% by weight or more, and most preferably 30% by weight or more, - Compounds selected from formula IA and IB in total of 40% by weight or more, more preferably 60% by weight, more preferably 75% by weight or more, and most preferably 90% by weight or more, that is, the sum of the compound represented by formula IA and the compound represented by formula IB is preferably at least one of the above values, - Compounds selected from formula IC-1, IC-2, and IC-3 at 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, and most preferably 25% by weight or more, - Compounds selected from formula IA, IB, and IC in total of 45% by weight or more, more preferably 70% by weight, more preferably 85% by weight or more, and most preferably 90% by weight or more, that is, the sum of the compounds represented by these formulas, - Optionally, a compound represented by formula ID (ID-1, ID-2, ID-3, ID-4) at 2% by weight or more, more preferably 5% by weight or more, more preferably 10% by weight or more, and most preferably 15% by weight or more, - One, two, three, or more compounds represented by formula IA-1-1 or IA-1-2, preferably represented by formula AUUQGU-nN, AUUQGG-nN, PGGUQU-nF, and most preferably selected from the group consisting of compounds AUUQGU-2-N, AUUQGU-3-N, AUUQGU-4-N, AUUQGU-5-N, and AUUQGU-6-N. - One, two, three, or more, preferably three or more, compounds represented by formula IB-1, preferably represented by formula GUUQU-n-N and / or DUUQU-n-N, and most preferably selected from the group consisting of compounds GUUQU-2-N, GUUQU-3-N, GUUQU-4-N, GUUQU-5-N, GUUQU-6-N, GUUQU-7-N, DUUQU-2-N, DUUQU-3-N, DUUQU-4-N, DUUQU-5-N, and DUUQU-6-N. - One, two, three, or more compounds represented by formula IB-1-3, preferably represented by formula GUUQU-n-N, and more preferably selected from the group consisting of compounds GUUQU-3-N, GUUQU-4-N, and GUUQU-5-N. - One, two, three, or more compounds represented by formula IB-3-1, preferably represented by formula DUUQU-n-F, and more preferably selected from the group consisting of compounds DUUQU-3-F, DUUQU-4-F, and DUUQU-5-F. - One, two, three, or more compounds represented by formula IC-1-1, preferably represented by formula MUZU-n-N or MUQU-n-N, and more preferably selected from the group consisting of compounds MUZU-2-N, MUZU-3-N, MUZU-4-N, and MUZU-5-N. - One, two, three, or more compounds represented by formula IC-3, preferably selected from formula IC-3-2 and IC-3-3, more preferably selected from formula MUU-n-N or UMU-n-N, and more preferably selected from the group consisting of compounds MUU-3-N, MUU-4-N, MUU-5-F, UMU-3-N, UMU-4-N, and UMU-5-N. - one, two, three, or more compounds represented by formula IC-1-1, preferably selected from formula GUZU-n-N or GUQU-n-N, more preferably selected from the group consisting of compounds GUZU-3-N, GUZU-4-N, GUZU-5-F, GUQU-3-N, GUQU-4-N, and GUQU-5-N, and / or - one, two, three, or more compounds of the group of formulas IC-1-1-3 and IC-1-1-4, preferably represented by formula UUZU-n-N and / or UUQU-n-N, most preferably selected from the group consisting of compounds UUZU-2-N, UUZU-3-N, UUZU-4-N, UUZU-5-N, UUQU-2-N, UUQU-3-N, and UUQU-4-N, wherein n is 1, 2, 3, 4, 5, 6, or 7.

[0053] In another preferred embodiment of the present invention, the compounds represented by formulas IA, IB, and IC-1 / -2 / -3 are the first group of compounds, group 1 of the compounds. In this embodiment, the concentration of the compounds of group 1 of this compound is preferably in the range from 70% or more, preferably from 80% or more, more preferably from 90% or more to 100% or less.

[0054] The medium according to the present disclosure optionally contains one or more compounds selected from the group of compounds (group 2) represented by formulas II and III, preferably at a concentration from more than 0% to 40% or less,

Chemical formula

Chemical formula

[0055] L 21 and L 22 displays H or F, preferably L 21 displays F, L 32 and L 33 displays H, F, or CH3, preferably H, X 2 is halogen, haloalkyl or alkoxy having 1 to 3 C atoms, or haloalkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, Cl, -OCF3, -O-CH2CF3, -O-CH=CH2, -O-CH=CF2, or -CF3, most preferably F, Cl, -O-CH=CF2, or -OCF3, and m is 0, 1, 2, or 3, preferably 1 or 2, most preferably 2, and R 3 is alkyl, alkoxy, fluorinated alkyl, or fluorinated alkoxy having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl, or fluorinated alkenyl having 2 to 7 C atoms, preferably n-alkyl, cyclopropyl, cyclopentyl, or alkenyl, and [Chemistry] is, each time it appears, independent of each other, as follows [Chemistry] Preferably [Chemistry] or

Chem.

[0056] L 31 and L 32 each independently represents H or F, preferably L 31 represents F, X 3 represents halogen, haloalkyl or alkoxy having 1 to 3 C atoms, or haloalkenyl or alkenyloxy having 2 or 3 C atoms, F, Cl, -OCF3, -OCHF2, -O-CH2CF3, -O-CH=CH2, -O-CH=CF2, -O-CH=CH2, or -CF3, very preferably F, Cl, -O-CH=CF2, -OCHF2, or -OCF3, Z 3 represents -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O- or a single bond, preferably -CH2CH2-, -COO-, trans-CH=CH-, or a single bond, very preferably -(CO)-O-, trans-CH=CH-, or a single bond, and n represents 0, 1, 2, or 3, preferably 1, 2, or 3, most preferably 1, wherein each ring, preferably the phenylene ring, may optionally be substituted by one or two alkyl groups, preferably by a methyl group and / or an ethyl group, preferably by one methyl group, and wherein the compounds represented by formulae IA, IB, IC, and ID are excluded from the compounds represented by formula II, again optionally, alternatively or in addition, contains one or more compounds selected from the group of compounds represented by formulae IV and V (Group 3), preferably in a concentration of more than 0% to 15%,

Chem.

[0057] In the formula R 41 and R 42 are, independently of each other, as defined above for R in formula II 2 and preferably R 41 represents alkyl, and R 42 represents alkyl or alkoxy, or R 41 represents alkenyl, and R 42 represents alkyl, [Chemical formula] are, independently of each other, and [Chemical formula] when they appear twice, these also, independently of each other, represent [Chemical formula] preferably one or more of the following [Chemical formula] (singular or plural) represents [Chemical formula] represents

[0058] Z 41 and Z 42 are, independently of each other, and also when Z 41 appears twice, these are, independently of each other, -CH2CH2-, -COO-, trans -CH=CH-, trans -CF=CF-, -CH2O-, -CF2-O-, -C≡C-, or a single bond, preferably one or more of them (singular or plural) represents a single bond, and p represents 0, 1, or 2, preferably 0 or 1, and R 51 and R 52 are, independently of each other, R41 and R 42 has one of the meanings given for, preferably alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl having 2 to 7 C atoms, preferably having 2 to 4 C atoms, alkenyl, or alkenyloxy, preferably alkenyloxy, and [Chemical formula] , when present, each independently represents [Chemical formula] [Chemical formula] preferably [Chemical formula] represents,

[0059] preferably [Chemical formula] is [Chemical formula] represents, and, when present, [Chemical formula] preferably represents [Chemical formula]

[0060] Z 51 ~Z 53Each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO-, or a single bond, preferably -CH2-CH2-, -CH2-O-, or a single bond, and particularly preferably a single bond, i and j each independently represent 0 or 1, (i + j) preferably represents 0, 1, or 2, more preferably 0 or 1, and most preferably 1, Each ring in the formula, preferably a phenylene ring, may optionally be substituted by one or two alkyl groups, preferably by a methyl group and / or an ethyl group, preferably by one methyl group, and Optionally again, alternatively or in addition, contains one or more compounds, preferably two, three, or more compounds, selected from Group 4 of the compounds represented by Formulas I and VI - IX, preferably at a concentration of more than 0% to 20%,

Chemical formula

[0061] In the formula

Chemical formula

Chemical formula

Chemical formula

[0062]

Chemical formula

Chemical formula

Chemical formula

[0063] n represents 0 or 1, and R 11 and R 12 each independently represent, preferably, alkyl, alkoxy, fluorinated alkyl, or fluorinated alkoxy having 1 to 7 carbon atoms, where one CH2 group may be replaced by a 1,2-cyclopropyl group, a 1,3-cyclopentyl group, or a 1,3-cyclopentenylene group, alkenyl, alkenyloxy, alkoxyalkyl, or fluorinated alkenyl having 2 to 7 carbon atoms, preferably alkyl, alkoxy, alkenyl, or alkenyloxy, most preferably alkyl, alkoxy, or alkenyloxy. R 61 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, an unsubstituted alkenyl radical having 2 to 7 carbon atoms, preferably a straight-chain alkenyl radical, particularly preferably one having 2 to 5 carbon atoms, an unsubstituted alkoxy radical having 1 to 6 carbon atoms, or an unsubstituted alkenyloxy radical having 2 to 6 carbon atoms. R 62 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, an unsubstituted alkoxy radical having 1 to 6 carbon atoms, or an unsubstituted alkenyloxy radical having 2 to 6 carbon atoms, and l represents 0 or 1, and R 71 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, or an unsubstituted alkenyl radical having 2 to 7 carbon atoms, preferably a straight-chain alkenyl radical, particularly preferably one having 2 to 5 carbon atoms. R 72represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, preferably 2 to 5 carbon atoms, an unsubstituted alkoxy radical having 1 to 6 carbon atoms, preferably 1, 2, 3, or 4 carbon atoms, or an unsubstituted alkenyloxy radical having 2 to 6 carbon atoms, preferably 2, 3, or 4 carbon atoms, and

Chem.

Chem.

[0064] R 81 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, preferably a linear alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, or an unsubstituted alkenyl radical having 2 to 7 carbon atoms, preferably a linear alkenyl radical, particularly preferably one having 2 to 5 carbon atoms, R 82 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms, preferably 2 to 5 carbon atoms, an unsubstituted alkoxy radical having 1 to 6 carbon atoms, preferably 1, 2, 3, or 4 carbon atoms, or an unsubstituted alkenyloxy radical having 2 to 6 carbon atoms, preferably 2, 3, or 4 carbon atoms,

Chem.

Chem.

Chem.

Chem.

[0065] Z 8 represents -(CO)-O-, -CH2-O-, -CF2-O-, or -CH2-CH2-, preferably -(CO)-O- or -CH2-O-, and o represents 0 or 1, R 91 and R 92 are, independently of each other, as defined for R above 72 and have the meaning given for R 91 preferably represents an alkyl radical having 2 to 5 C atoms, preferably 3 to 5 C atoms, R 92 preferably represents an alkyl radical or an alkoxy radical having 2 to 5 C atoms, more preferably an alkoxy radical having 2 to 4 C atoms, or an alkenyloxy radical having 2 to 4 C atoms.

[0066]

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0067] In the formula, each ring, preferably a phenylene ring, may each optionally be substituted by one or two alkyl groups, preferably by a methyl group and / or an ethyl group, preferably by one methyl group, and in the formula, in particular the ring

Chemical formula

Chemical formula

Chemical formula

[0068] wherein

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0069] n represents 0, 1, or 2, preferably 1, R 1 represents an alkyl radical having 1 to 7 C atoms, where one or more CH2 groups in this radical, preferably one CH2 group, are each, independently of one another, -C≡C-, -CF2-O-, -OCF2-, -O-, -(CO)-O-, -O-(C=O)-, cyclo-propylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclo-pentenylene, preferably by cyclo-propylene or 1,3-cyclopentylene, and preferably one CH2 group is replaced by a 1,2-cyclopropylene group, by a 1,3-cyclopentylene group, or by a 1,3-cyclopentenylene group, alkenyl having 2 to 7 C atoms, alkenyloxy, alkoxyalkyl, or fluorinated alkenyl, preferably by alkyl or alkenyl, where one -CH2- group may be replaced by cyclo-propylene, 1,3-cyclobutylene, 1,3-cyclopentylene, 1,3-cyclo-pentenylene so that O atoms are not directly linked to each other, preferably by cyclo-propylene or 1,3-cyclopentenylene, and one or more H atoms in the said radical may be replaced by halogen, and X 1 represents F, Cl, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy, or a fluorinated entity, the latter four groups preferably having 1 to 4 C atoms, more preferably representing F, Cl, CF3, or OCF3, and In the formula, each ring, preferably a phenylene ring, may each optionally be substituted by one or two alkyl groups, preferably by a methyl group and / or an ethyl group, preferably by one methyl group.

[0070] Preferably, it is a medium containing one or more compounds of Groups 1 and 2. The corresponding starting materials can generally be readily prepared by those skilled in the art by synthetic methods known from the literature or are commercially available. The reaction methods and reagents used are in principle known from the literature.

[0071] In the present disclosure, the formula

Chemical formula

Chemical formula

[0072] The liquid crystal medium according to the invention has a wide temperature range of the ferroelectric nematic phase. It exhibits a ferroelectric nematic phase range at 20° and below (ambient temperature). It occupies the most technically interesting range from at least 10 °C to 50 °C and significantly beyond this, to lower and / or higher temperatures. Seen thus, it is very suitable for all kinds of household use or industrial use and, with some limitations, also for outdoor use. The medium exhibits a ferroelectric nematic phase over a temperature range of at least 20 Kelvin, more preferably over 30 K, most preferably over 40 K. Preferably, the medium exhibits an enantiotropic ferroelectric nematic phase, i.e., a ferroelectric nematic phase in a certain temperature range that appears when cooled from a higher temperature as well as when heated from a lower temperature. The achievable combinations of the temperature range, clearing point, low temperature stability (LTS), (relative) permittivity, dielectric anisotropy, and optical anisotropy of the ferroelectric nematic phase containing the compounds of formulae IA, IB, and IC-1 / -2 / -3 are far superior to such prior materials of this kind from the prior art. Hitherto, only single compound materials with a limited ferroelectric nematic phase range have been available and the options have been limited.

[0073] In addition, the mixture according to the invention generally exhibits a very wide nematic phase range with a clearing point of 65 °C or higher. The liquid crystal medium according to the invention preferably exhibits a temperature range of the ferroelectric nematic phase with a width of 20 degrees or more, preferably it extends over a range of 40 degrees or more, more preferably 60 degrees or more.

[0074] Preferably, the liquid crystal medium according to the invention exhibits a ferroelectric nematic phase, preferably from 10 °C to 30 °C, more preferably from 10 °C to 40 °C, more preferably from 10 °C to 50 °C, more preferably from 0 °C to 50 °C, most preferably from -10 °C to 50 °C.

[0075] In another preferred embodiment, the liquid crystal medium according to the present invention exhibits a ferroelectric nematic phase, preferably from 10°C to 40°C, more preferably from 10°C to 50°C, more preferably from 10°C to 60°C, and most preferably from 10°C to 70°C. The liquid crystal medium according to the present invention exhibits excellent dielectric properties.

[0076] Due to their excellent properties, the media can function in many new technical fields and can be used for electro-optical purposes, such as for supercapacitors, non-linear optical elements, sensors for electric fields, memory devices, and electromechanical devices including generators (i.e., energy harvesting devices) and actuators. The materials may also enable unconventional modes, for example, to harvest energy from vibrational motion.

[0077] Preferably, the medium according to the present invention has an ε value of 700 or more, more preferably 800 or more, more preferably 15000, even more preferably 30000 or more, and more preferably 35000 or more r at (20°C and 10 Hz).

[0078] These dielectric properties are realized at the temperature at which the medium is in the ferroelectric nematic phase. The dielectric characteristics may specifically exhibit hysteresis behavior over various temperatures, and in that case, the value obtained at a certain temperature may depend on the history of the material, i.e., whether the material has been heated or cooled.

[0079] This effect enables, among other things, the operation of devices, for example, the operation of devices in a bistable mode, which may be beneficially used in electro-optical devices, as is known, for example, from ferroelectric smectic devices.

[0080] The liquid crystal medium according to the invention, in addition to one or more compounds according to the invention, preferably contains, as further constituent substances, from 2 to 40, particularly preferably from 4 to 20 compounds. In particular, these media may contain, in addition to one or more compounds according to the invention, from 1 to 25 constituents. These further constituent substances are preferably selected from ferroelectric nematic substances or nematogenic (monotropic or isotropic) substances.

[0081] For combinations with the present substances, prior art ferroelectric substances and similar compounds with a high dielectric constant are selected, for example, from the following structures:

Chemical formula

Chemical formula

[0082] The medium according to the invention preferably contains from 1% to 100%, more preferably from 10% to 100%, particularly preferably from 50% to 100% of the compounds represented by formula IA and / or IB and / or IC-1 / IC-2 / IC-3 which are preferably used according to the invention.

[0083] The invention also relates to a method for preparing the liquid crystal medium described herein, wherein at least two or more selected compounds represented by formula IA, optionally one or more compounds represented by formula IB and IC, and any other constituent or additive are combined and mixed with each other. The resulting mixture reaches 100% by weight.

[0084] The liquid crystal mixtures according to the invention are prepared in a manner that is conventional per se. Generally, the desired amounts of the components used in smaller amounts are dissolved, preferably at elevated temperature, in the components that make up the main constituent. It is also possible to mix solutions of the components in an organic solvent, for example acetone, chloroform, or methanol, and, after thorough mixing, to remove the solvent again, for example by distillation. Furthermore, it is also possible to prepare the mixtures in other conventional manners, for example by using premixes, such as homologue mixtures, or by using so-called "multi-bottle" systems.

[0085] The liquid crystal mixtures may also contain further additives that are known to the person skilled in the art and are described in the literature. For example, 0 to 15%, preferably 0 to 10%, of a dichroic dye, a chiral dopant, a stabilizer, or nanoparticles can be added. The individual compounds added are employed at a concentration of 0.01 to 6%, preferably 0.1 to 3%. However, the concentration data of the other constituents of the liquid crystal mixture, i.e., the liquid crystals or mesogenic compounds, are given here without taking into account the concentrations of these additives.

[0086] The liquid crystal mixtures according to the invention allow for a significant broadening of the available parameter tolerance ranges.

[0087] The invention also relates to electro-optical devices, preferably displays (in particular TFT displays having two parallel planar outer plates that form a cell together with a frame, non-linear elements integrated to switch the individual pixels on the outer plates, and a ferroelectric nematic liquid crystal material having positive dielectric anisotropy and high resistivity positioned in the cell), which contain media of this type, and to the use of these media for electro-optical purposes.

[0088] The expression "alkyl" encompasses unbranched and branched alkyl groups having from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, and most preferably unbranched groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-heptyl, and alternatively also n-butyl, n-pentyl, n-hexyl, and n-heptyl substituted by one methyl, ethyl, or propyl. Groups having from 1 to 5 carbon atoms are generally preferred.

[0089] The expression "alkenyl" encompasses unbranched and branched alkenyl groups having up to 12 carbon atoms, and especially unbranched groups. Particularly preferred alkenyl groups are C2-C7-1E-alkenyl, C4-C7-3E-alkenyl, C5-C7-4-alkenyl, C6-C7-5-alkenyl, and C7-6-alkenyl, especially C2-C7-1E-alkenyl, C4-C7-3E-alkenyl, and C5-C7-4-alkenyl. Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl, etc. Groups having from 2 to 5 carbon atoms are generally preferred.

[0090] The expression "halogenated alkyl radical" preferably encompasses mono- or polyfluorinated and / or -chlorinated radicals. Perhalogenated radicals are also included. Particularly preferred are fluorinated alkyl radicals, especially CH2CF3, CH2CHF2, CHF2, CH2F, CHFCF3, and CF2CHFCF3. The expression "halogenated alkenyl radical" and related expressions are correspondingly defined.

[0091] The construction of the polarizer, electrode base plate, and surface treatment electrode of the matrix display according to the present invention corresponds to the conventional arrangement for this type of display. The term "conventional arrangement" is taken broadly here and encompasses all derivatives and modifications of matrix displays, and in particular also matrix display elements based on poly-Si TFTs.

[0092] However, the essential difference between the display according to the present invention and the conventional products heretofore based on the twisted nematic cell consists in the selection of the liquid crystal parameters of the liquid crystal layer.

[0093] The following examples are illustrative of the present invention and are not intended to limit the present invention. Those skilled in the art will be able to gather working details not given in detail in the general description from the examples, generalize them according to general expertise, and apply them to specific problems.

[0094] The upper and lower percentage data represent weight percentages. All temperature values indicated in this application, for example, the melting point T(C,N), the smectic (Sm)-nematic (N) phase transition T(S,N), and the clearing point T(N,I), each T(N f ,I), etc. are indicated in degrees Celsius (°C), and all temperature differences are correspondingly indicated in differential degrees (° or degrees) unless otherwise explicitly indicated. Further, C = crystalline state, N = nematic phase, Nf = ferroelectric nematic phase, Sm = smectic phase (more particularly SmA, SmB, etc.), Tg = glass transition temperature, and I = isotropic phase. The data between these symbols represent transition temperatures. Δn represents the optical anisotropy (589 nm, 20 °C), and Δε represents the dielectric anisotropy (1 kHz, 20 °C).

[0095] Physical parameters, physicochemical parameters, and electro-optical parameters are determined by generally known methods, in particular, as described in the brochure "Merck Liquid Crystals - Licristal® - Physical Properties of Liquid Crystals - Description of the Measurement Methods", 1998, Merck KGaA, Darmstadt.

[0096] The occurrence of the ferroelectric nematic phase of the material is identified through the observation of textures under a polarized light microscope equipped with a hot stage for controlled cooling and heating, respectively, using differential scanning calorimetry (DSC), and is additionally confirmed by measuring the temperature dependence of the dielectric properties. The transition temperatures are determined mainly by detecting the optical behavior under a polarized light microscope.

[0097] The dielectric anisotropy Δη of the individual substances is determined at 20 °C and 1 kHz. For this purpose, 5 to 10 wt% of the substances to be investigated are dissolved in the dielectrically positive mixture ZLI-4792 (Merck KGaA) and measured, and the measured values are extrapolated to a concentration of 100%. The optical anisotropy n is determined by linear extrapolation at 20 °C and a wavelength of 589.3 nm.

[0098] The relative permittivity (ε r) is directly determined by measuring the capacitance of at least one test cell containing the compound and having a cell thickness of 250 μm in each of the homeotropic and homogeneous orientations, especially in the ferroelectric nematic phase. The temperature is controlled by a Novocontrol Novocool system set to a temperature gradient of + / - 1K / min, + / - 2K / min, + / - 5K / min, + / - 10K / min applied to the sample cell. The capacitance is measured by a Novocontrol alpha-N analyzer at a frequency of 1 kHz or 10 Hz with a typical voltage of less than <50 mV (down) to 0.1 mV to ensure that it is below the threshold of the compound under investigation. The measurements are carried out both during heating and cooling of the sample(s).

[0099] In the present application, unless otherwise expressly indicated, the plural forms of terms include both the singular and plural forms, and vice versa. Further combinations of aspects and variations of the present invention according to this description also emerge from the appended claims or from combinations of a plurality of these claims.

[0100] Further combinations of aspects of the current invention and variations of the invention are also disclosed by the claims.

[0101] Without further elaboration, it is believed that one of ordinary skill in the art can, using the preceding description, utilize the present invention to its fullest extent. Accordingly, the preceding preferred specific embodiments should be construed merely as illustrative and not limit in any way the remainder of the present disclosure. The preceding examples can be repeated with similar success by substituting the reactants and / or operating conditions of the present invention, which are described generally or specifically, with those used in the preceding examples.

[0102] From the above description, those skilled in the art can easily clarify the essential features of the present invention and, without departing from the spirit and scope of the present invention, can adapt the present invention to various uses and conditions by making various changes and modifications to the present invention.

[0103] This applies not only to compositions and the media as their constituent substances (the said constituent substances can be groups of compounds as well as individual compounds), but also to groups of compounds and the compounds which are their respective constituent substances. Only with respect to the concentration of the individual compounds compared to the medium as a whole, the term includes the average: the concentration of the compound(s) in question is preferably 1% or more, more preferably 2% or more, and very specifically preferably 4% or more.

[0104] For the present invention, "≦" preferably means less than the following, and "≧" means greater than or equal to, preferably greater.

[0105] For the present invention,

Chem.

Chem.

Chem.

[0106] Regarding the present invention, the expression "dielectrically positive compound" means a compound having Δε > 1.5, the expression "dielectrically neutral compound" means a compound having -1.5 ≤ Δε ≤ 1.5, and the expression "dielectrically negative compound" means a compound having Δε < -1.5. The dielectric anisotropy of the compound is here determined by dissolving 10% of the compound in the liquid crystal host and each time determining the capacitance of the resulting mixture at 1 kHz in at least one test cell having a cell thickness of 20 μm with a homeotropic and uniform surface orientation. The measurement voltage is typically 0.5 V to 1.0 V, but always lower than the capacitive threshold of each liquid crystal mixture (material) being investigated.

[0107] The host mixture used for dielectrically positive compounds and dielectrically neutral compounds is ZLI-4792, and the one used for dielectrically negative compounds is ZLI-2857, both from Merck KGaA, Germany. The value of each compound to be investigated is obtained from the change in the dielectric constant of the host mixture after the addition of the compound to be investigated and the extrapolation to 100% of the compound employed. The compound to be investigated is dissolved in the host mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is stepwise halved until the investigation can be carried out at the desired temperature.

[0108] Also, the liquid crystal medium according to the present invention may, if necessary, contain further additives such as stabilizers in customary amounts, for example. The amount of these additives employed is preferably 0% or more and 10% or less, particularly preferably 0.1% or more and 6% or less, based on the amount of the total mixture. The concentration of each individual compound employed is preferably 0.1% or more and 3% or less. The concentration of these additives and similar additives is generally not taken into account when specifying the concentration and concentration range of the liquid crystal compounds in the liquid crystal medium.

[0109] For the purposes of the present invention, all concentrations are given as weight percentages unless expressly stated otherwise and relate to the corresponding mixture as a whole or to the constituents of the mixture as a whole, unless expressly indicated otherwise. In this context, the term "mixture" describes a liquid crystal medium.

[0110] The following symbols are used, unless expressly indicated otherwise: T(N,I) each T(N f ,I) (or clp.) clearing point [°C], Dielectric properties at 1 kHz and preferably at 20 °C or at each of the specified temperatures: ε ⊥ Dielectric susceptibility perpendicular to the waveguide, ε || Dielectric susceptibility parallel to the waveguide, Δε dielectric anisotropy, especially for screening data of single compounds.

[0111] And especially for data from the screening of each compound in the nematic host mixture ZLI-4792: n e Anomalous refractive index measured at 20 °C and 589 nm, n o Ordinary refractive index measured at 20 °C and 589 nm, and Δn optical anisotropy measured at 20 °C and 589 nm.

[0112] The following examples illustrate the invention without limiting it. However, they show the person skilled in the art the concept of preferred mixtures and the compounds preferably to be employed, and their respective concentrations, and their combinations with one another. In addition, the examples illustrate accessible properties and combinations of properties.

[0113] Definition of structural elements by abbreviations used as the initials of chemical compounds: Table A: Ring Elements

Table A-1

[0114]

Table A-2

[0115]

Table A-3

[0116] Table B: Crosslinking Units

Table B-1

Table B-2

[0117] Table C: End Groups

Table C

[0118] In addition to the compounds represented by Formulas IA, IB, and IC-1 / -2 / -3, the mixtures according to the invention preferably contain one or more of the compounds mentioned below.

[0119] The following abbreviations are used: (n, m, k, and l are each, independently of one another, integers, preferably from 1 to 9, preferably from 1 to 7, k and l may also, according to circumstances, be 0, preferably from 0 to 4, more preferably 0 or 2, most preferably 2, n is preferably 1, 2, 3, 4, or 5, and in the combination "-nO-" it is preferably 1, 2, 3, or 4, preferably 2 or 4, m is preferably 1, 2, 3, 4, or 5, and in the combination "-Om" it is preferably 1, 2, 3, or 4, preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0120] For the present invention and in the following examples, the structure of the liquid crystal compounds is indicated using initials, and the conversion to chemical formulas is carried out according to Tables A - C above. All radicals C n H 2n+1 、C m H 2m+1 、and C l H 2l+1 、or C n H 2n 、C m H 2m 、and C l H 2l are each a straight-chain alkyl radical or an alkylene radical, having n, m, and l C atoms each time. Preferably, n, m, and l are, independently of one another, 1, 2, 3, 4, 5, 6, or 7. Table A shows the codes for the ring elements of the nucleus of the compound, Table B lists the bridging units, and Table C lists the meanings of the symbols relating to the left- and right-hand end groups of the molecule. The initials consist of the code for the ring element with any linking group, followed by the code for the first hyphen and the left-hand end group, and the code for the second hyphen and the right-hand end group. Table D shows the exemplary structures of the compounds together with their respective abbreviations.

[0121] Table D Exemplary preferred compounds of formula IA

Chemical formula

Chem.

[0122] Exemplary preferred compounds represented by formula IB

Chem.

[0123] Exemplary preferred compounds represented by formula IC-1

Chem.

[0124] Exemplary preferred compounds represented by formula IC-3

Chem.

[0125] Optionally used additional compounds

Chem.

[0126]

Chem.

[0127]

Chem.

[0128]

Chem.

[0129] Examples of Mixtures In the following, exemplary mixtures are disclosed. Example 1 of Mixtures Prepare and investigate the following mixture (M-1).

Table 1

[0130] The mixture has a monotropic ferroelectric nematic phase from a temperature above the melting point (67 °C) to about -20 °C when cooled.

[0131] Example 2 of Mixtures Prepare and investigate the following mixture (M-2).

Table 2

[0132] Example 3 of Mixtures Prepare and investigate the following mixture (M-3).

Table 3

[0133] Example 4 of Mixtures Prepare and investigate the following mixture (M-4).

Table 4

[0134] Example 5 of Mixtures Prepare and investigate the following mixture (M-5).

Table 5

[0135] Example 6 of Mixtures Prepare and investigate the following mixture (M-6).

Table 6

[0136] Example 1 of the device A capacitor including two glass substrates with ITO electrodes is filled with a 110-μm dielectric layer made of the medium of Example 4 of the mixture. A capacitance of 1.41 μF is determined using a 10-Hz AC voltage. The relative permittivity (ε r ) of the resulting medium is 4.0·10 4 is.

Claims

1. A ferroelectric nematic liquid crystal medium comprising one or more compounds represented by formula IA, 【Chemical 1】 wherein X 1A represents -CN, F, or -NCS, and Z 1A and Z 2A is, independently of each other, -(CO)-O- or -CF 2 -O- or a single bond, L 1A is H or CH 3 and L 2A is, independently, F or H, and L 3A is, independently, F or H, and L 4A is, independently, F or H, A 1A is 【Chemical 2】 is shown as R 1A is, independently, an alkyl radical having 1 to 12 carbon atoms, where, in addition, one or more CH 2 groups are, each time independently of one another, such that the O / S atoms are not directly linked to one another, -C≡C-, -CF 2 -O-, -OCF 2 -, -CH=CH- 【Chemical Formula 3】 which may be replaced by -O-, -S-, -(CO)-O-, or -O-(CO)-, and wherein, in addition, one or more H atoms may be replaced by halogen, or H is shown, n1, n2 are independently 0 or 1, and n3 is either 2 or 3, while when n1 + n2 + n3 is 2, one or more of 1A is 【Chemical Formula 4】 such is the liquid crystal medium.

2. The liquid crystal medium according to claim 1, comprising one or more compounds selected from the following formula IB or IC: [Chemical Formula 5] wherein X 1B is -CN, F, or -NCS, X 1C is -CN, F, CF 3 , -OCF 3 , -NCS, SF 5 , or O-CF=CF 2 and preferably displays -CN, Z 1A and Z 2A are, independently of each other, a single bond, -(CO)-O-, or -CF 2 -O-, and Z 1C and Z 2C wherein one of the two groups is -(CO)-O- or -CF 2 -O-, and the other is a single bond, L 1B is independently H or CH 3 and L 2B is F or H, and A 1A is [Chemical Formula 6] is shown as wherein L 8B represents alkyl, alkoxy, or alkoxyalkyl, each having 1 to 7 C atoms, A 1C is 【Chemical Formula 7】 is shown as A 2C is 【Chemical Formula 8】 is shown as A 3C is 【Chemical Formula 9】 is shown as, and R 1B and R 1C each independently represents an alkyl radical having 1 to 12 carbon atoms, where in addition, one or more CH 2 groups in these radicals are each independently, such that O / S atoms are not directly linked to each other, -C≡C-, -CF 2 -O-, -OCF 2 -, -CH=CH-, 【Chemical Formula 10】 which may be replaced by -O-, -S-, -(CO)-O-, or -O-(CO)-, and wherein, in addition, one or more H atoms may be replaced by halogen, or H is shown.

3. The liquid crystal medium according to claim 1 or 2, comprising 15% by weight or more of a compound represented by formula IA.

4. A liquid crystal medium according to any one of claims 1 to 3, having a relative permittivity ε of 700 or more at 20°C and 1 kHz. r ​

5. The liquid crystal medium according to any one of claims 1 to 4, comprising in total at least 80% of the compounds represented by formula IA, IB, and IC.

6. The medium according to any one of claims 1 to 5, which exhibits a ferroelectric nematic phase at a temperature of at least 10 °C to 30 °C when cooled from a high temperature.

7. The medium according to any one of claims 1 to 6, which exhibits hysteresis in its dielectric identification over a varying temperature.

8. The medium according to any one of claims 1 to 7, which exhibits an enantiotropic ferroelectric nematic phase.

9. Use of the liquid crystal medium according to at least one of claims 1 to 8 for electro-optical purposes, for supercapacitors and for electromechanical devices including generators and electric actuators.

10. Use of the liquid crystal medium according to at least one of claims 1 to 8 for non-linear optical elements, sensors, or memory devices.

11. An electro-optical liquid crystal device comprising the liquid crystal medium according to at least one of claims 1 to 8.

12. A method for preparing the liquid crystal medium according to any one of claims 1 to 8, wherein at least one or more compounds represented by formula IA, optionally one or more compounds selected from formula IB and IC, and any other components or additives are combined and mixed with each other.

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