Liquid crystal composition suitable for guest-host liquid crystal and application thereof

Abstract

The invention provides a liquid crystal composition which has a higher clearing point and higher dielectric anisotropy, can dissolve more dichroic dyes when being applied to guest-host liquid crystals, and has higher thermal stability.

Description

Technical Field

[0001] The present invention relates to a liquid crystal composition, a guest-host liquid crystal derived therefrom and the application of the liquid crystal composition in a light valve, a switchable window, a switchable mirror and a guest-host display. Background Art

[0002] Guest-host liquid crystal is a liquid crystal material based on the guest-host effect. The so-called guest-host effect refers to the interaction between the host liquid crystal molecules and the dichroic dye molecules, which makes the dye molecules follow the host liquid crystal molecules to arrange in an orderly manner. When driven by an external electric field, the dichroic dye molecules rotate with the rotation of the host liquid crystal molecules. Since the long axis and short axis directions of the dichroic dye molecules have different light absorption capabilities, when they change direction with the rotation of the host liquid crystal molecules, the overall light absorption capacity of the guest-host liquid crystal also changes accordingly, thereby achieving electrochromic and color display effects.

[0003] In recent years, as people continue to pursue a higher quality of life, the application areas of guest-host liquid crystals have continued to expand. For example, the color-changing sunroof of cars, the color-changing glass inside and outside buildings, the color-changing side windows on large public transportation vehicles, and smart glasses that change color with the intensity of external light are all emerging application scenarios of guest-host liquid crystals.

[0004] However, dichroic dyes have problems of low solubility and insufficient stability, which limits the performance and application scenarios of guest-host liquid crystals. The interaction between dichroic dyes and host liquid crystals has a great influence on their solubility and stability. Studies have shown that the intermolecular hydrogen bonds generated by the interaction between dichroic dye molecules and host liquid crystal molecules help improve the solubility and stability of dichroic dyes. Summary of the invention

[0005] Purpose of the invention: The main purpose of the present invention is to provide a liquid crystal composition, which has a higher clearing point, a higher dielectric anisotropy, can dissolve more dichroic dyes when used in guest-host liquid crystals, and has higher thermal stability.

[0006] Technical solution: In order to achieve the above-mentioned object, the present invention provides a liquid crystal composition, characterized in that the liquid crystal composition comprises at least one liquid crystal compound of component I, at least one liquid crystal compound of component II, and at least one liquid crystal compound of component III;

[0007] The component I is a liquid crystal compound having a general formula I, and the general formula I is as follows:

[0008]

[0009] n is 1 or 2;

[0010] When n is 1, Selected from

[0011] When n is 2, the components include two Right now appears twice in the component,

[0012] Each time it occurs, it is independently

[0013] R1 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups;

[0014] The component II is a liquid crystal compound having a general formula II, and the general formula II is as follows:

[0015]

[0016] R2 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups;

[0017] X1 and X2 are each independently selected from H or F, and at least one of X1 and X2 is F;

[0018] The component III is a liquid crystal compound having a general formula III, and the general formula III is as follows:

[0019]

[0020] R3 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted with an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0021] The liquid crystal composition further comprises one or more dichroic dyes, wherein the dichroic dyes are selected from compounds represented by formulas B1 to B16, and formulas B1 to B16 are as follows:

[0022] B1.

[0023] B2,

[0024] B3,

[0025] B4,

[0026] B5,

[0027] B6, B7, B8, B9, B10, B11, B12,

[0028] B13,

[0029] B14,

[0030] B15,

[0031] B16,

[0032] Wherein, R5 and R5' are each independently an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; and the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0033] According to another aspect of the present invention, there is provided a use of the above-mentioned liquid crystal composition in a liquid light valve, a switchable window, a switchable mirror and a guest-host display.

[0034] Beneficial effects: The liquid crystal composition provided by the present invention has a higher clearing point and a higher dielectric constant anisotropy. When used in guest-host liquid crystals, it has a higher solubility for dichroic dyes and has good thermal stability. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0036] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0037] In order to solve the above problems, in a typical embodiment of the present invention, a liquid crystal composition is provided, characterized in that the liquid crystal composition comprises at least one liquid crystal compound of component I, at least one liquid crystal compound of component II, and at least one liquid crystal compound of component III;

[0038] The component I is a liquid crystal compound having a general formula I, and the general formula I is as follows:

[0039]

[0040] n is 1 or 2;

[0041] When n is 1, Selected from

[0042] When n is 2, the components include two Right now appears twice in the component,

[0043] Each time it occurs, it is independently

[0044] R1 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups;

[0045] The component II is a liquid crystal compound having a general formula II, and the general formula II is as follows:

[0046]

[0047] R2 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups;

[0048] X1 and X2 are each independently selected from H or F, and at least one of X1 and X2 is F;

[0049] The component III is a liquid crystal compound having a general formula III, and the general formula III is as follows:

[0050]

[0051] R3 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted with an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0052] In an embodiment of the present invention, the component I is selected from one or more liquid crystal compounds represented by formulas A1 to A5, wherein formulas A1 to A5 are as follows:

[0053] A1. A2.

[0054] A3. A4,

[0055] A5.

[0056] Wherein, R4 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0057] In an embodiment of the present invention, the mass content of component I in the liquid crystal composition is 30-70%, the mass content of component II is 10-40%, and the mass content of component III is 5-35%.

[0058] In an embodiment of the present invention, the liquid crystal composition further comprises a non-polar liquid crystal compound represented by formula C1 to C3, and formula C1 to C3 are as follows:

[0059] C1. C2, C3,

[0060] Wherein, R6 and R6' are each independently selected from an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0061] In an embodiment of the present invention, the liquid crystal composition further comprises polar liquid crystal compounds represented by formulae D1 to D16, wherein formulae D1 to D16 are as follows:

[0062] D1. D2, D3, D4, D5. D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, D16,

[0063] In an embodiment of the present invention, the liquid crystal composition further comprises one or more dichroic dyes. The one or more dichroic dyes are selected from compounds represented by formulas B1 to B16, and formulas B1 to B16 are as follows:

[0064] B1. B2. B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14,

[0065] B15,

[0066] B16,

[0067] Wherein, R5 and R5' are each independently selected from an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

[0068] In an embodiment of the present invention, the mass fraction of the dichroic dye is 0.1 to 30%.

[0069] The dichroic dyes mentioned in the embodiments of the present invention are all independently synthesized, and the raw materials used for the synthesis can be obtained through commercial channels.

[0070] In the embodiment of the present invention, a chiral agent with a mass fraction of 0 to 20% may be added to the liquid crystal composition, and the chiral agent includes but is not limited to the following:

[0071]

[0072]

[0073] The liquid crystal compounds of components I to III are all compounds containing a cyano structure. The cyano group is a group in which a carbon atom and a nitrogen atom are connected by a triple bond. Since the electronegativity of nitrogen is greater than that of carbon, the cyano group has a stronger polarity. Therefore, the compounds containing cyano groups shown in components I to III have a higher dielectric constant, which is beneficial to reducing the driving voltage. The combination of different types of cyano compounds in components I to III is beneficial to adjusting the composition to have a suitable optical anisotropy value, clearing point and improving mutual solubility.

[0074] The dichroic dye molecule usually contains a hydroxyl group or an amino group. Since the nitrogen atom on the cyano group contains a lone electron pair and has a strong polarity, it can form an intermolecular hydrogen bond with the hydrogen on the hydroxyl group or the amino group, thereby effectively improving the solubility and stability of the dichroic dye in the liquid crystal composition. In addition, component III is a liquid crystal compound containing an ester structure, and the oxygen in the ester group can also form an intermolecular hydrogen bond with the dichroic dye molecule, further improving its solubility and stability in the liquid crystal composition.

[0075] The liquid crystal composition provided by the present invention can be prepared according to conventional methods. Usually, the required amount of components is dissolved in the components constituting the main component in a relatively low amount at high temperature; the solutions of the components can also be mixed into an organic solvent such as acetone, chloroform or methanol, and the solvent is removed again after sufficient mixing, for example, by distillation.

[0076] The preparation method of the guest-host liquid crystal composition provided by the present invention comprises dissolving a dichroic dye in the liquid crystal composition, heating the composition to 110° C. and stirring the composition for more than 24 hours.

[0077] The preparation method of the test unit of the dye liquid crystal composition provided by the present invention is to inject the dissolved dye liquid crystal composition into a horizontally oriented liquid crystal box through capillary phenomenon. The thickness of the liquid crystal box is 3-20 μm.

[0078] In a typical embodiment of the present invention, the thickness of the guest-host liquid crystal composition layer is 9 μm.

[0079] In another typical embodiment of the present application, there is provided an application of the above-mentioned liquid crystal composition in a light valve, a switchable window, a switchable mirror and a guest-host display.

[0080] _The beneficial effects of the present invention will be further illustrated below in combination with embodiments and comparative examples.

[0081] The following examples are used to explain the present invention but not to limit it. The percentages in the examples are all mass percentages and the temperatures are expressed in degrees Celsius. The measured physicochemical parameters are expressed as follows: NI represents the clearing point; △n represents the optical anisotropy (△n=n e -n o , 589nm, measurement temperature 25°C); △ε represents dielectric anisotropy (△ε=ε ∥ -ε ⊥ , 25℃); K 11 Indicates the splay elastic coefficient (measurement temperature 25°C); K 33 Indicates the bending elastic coefficient (measured at 25°C), τ 亮 Indicates the bright state transmittance (when the driving voltage is 0V, it is the bright state); τ 暗represents the dark state transmittance (when the driving voltage is 48V, it is the dark state); CIE x, y represents the color coordinates, and the color coordinates use the CIE1931 standard colorimetric system. And DSC is used to measure T NI ; △n was measured by Abbe refractometer; △ε and K were measured by CV 11 and K 33 ; A digital synthetic function signal generator is used to drive the test unit of the dye liquid crystal composition, the driving voltage is 0-48V, the waveform is a square wave, and the thickness of the dye liquid crystal composition layer of the test unit is 9μm; a haze meter is used to test τ 亮 and τ 暗 ; Use a color analyzer to measure the color coordinates.

[0082] In various embodiments of the present invention, the main chain of the liquid crystal molecule is named: cyclohexyl Represented by the letter C; phenyl Represented by the letter P; phenyl with single fluorine substitution on the left The letter H2 represents a phenyl group with a single fluorine substitution on the right side. Indicated by the letter H1; the corresponding codes for specific group structures are shown in Table 1:

[0083] Table 1

[0084]

[0085] Each compound branch chain is converted into a chemical formula according to Table 2 below, with the left-side branch chain represented by R1 and the right-side branch chain represented by R2. n H 2n+1 and C m H 2m+1 are straight-chain alkyl radicals having n and m carbon atoms respectively, Cp represents cyclopentyl C n H 2n+1 Cp represents a cyclopentyl group with a straight-chain alkyl group of n carbon atoms. The main chain is separated from the branch chain and the branch chain is separated from the branch chain. The main chain is in front and the branch chain is in the back when naming. For example, Indicated by CMPP-2-N; Expressed as CPP-3-N, Indicated by PH1P-3-N; Indicated by CC-3-V.

[0086] Table 2

[0087] Code R1 R2 nm <![CDATA[C n H 2n+1 ]]> <![CDATA[C m H 2m+1 ]]> n-Om <![CDATA[C n H 2n+1 ]]> <![CDATA[OC m H 2m+1 ]]> nO-Om <![CDATA[OC n H 2n+1 ]]> <![CDATA[OC m H 2m+1 ]]> n-Cp <![CDATA[C n H 2n+1 ]]> Cp n-mCp <![CDATA[C n H 2n+1 ]]> <![CDATA[C m H 2m+1 Cp]]> nF <![CDATA[C n H 2n+1 ]]> F Cp-m Cp <![CDATA[C m H 2m+1 ]]> Cp-Om Cp <![CDATA[OC m H 2m+1 ]]> CpO-Om OCp <![CDATA[OC m H 2m+1 ]]> Cp-F Cp F nCp-m <![CDATA[C n H 2n+1 Cp]]> <![CDATA[C m H 2m+1 ]]> nCp-Om <![CDATA[C n H 2n+1 Cp]]> <![CDATA[OC m H 2m+1 ]]> nCpO-Om <![CDATA[C n H 2n+1 CpO]]> <![CDATA[OC m H 2m+1 ]]> nCp-F <![CDATA[C n H 2n+1 Cp]]> F n-OCp <![CDATA[C n H 2n+1 ]]> OCp n <![CDATA[C n H 2n+1 ]]> CN nO-N <![CDATA[OC n H 2n+1 ]]> CN nV <![CDATA[C n H 2n+1 ]]> CH=CH2

[0088] In order to obtain a nearly total absorption effect in the visible light range, dichroic dyes of formulas B3, B13 and B16 are selected to form a mixed dye G1 that is close to black. The mass ratio of the dichroic dyes B3, B13 and B16 is 2.4:0.9:1.1.

[0089] Liquid crystal composition examples

[0090] Example M1

[0091] The composition and measurement parameters of the liquid crystal composition of Example M1 are shown in Table 3

[0092] Table 3

[0093]

[0094] Example M2

[0095] The composition and measurement parameters of the liquid crystal composition of Example M2 are shown in Table 4

[0096] Table 4

[0097]

[0098] Example M3

[0099] The composition and measurement parameters of the liquid crystal composition of Example M3 are shown in Table 5

[0100] Table 5

[0101]

[0102] Embodiment M4

[0103] The composition and measurement parameters of the liquid crystal composition of Example M4 are shown in Table 6

[0104] Table 6

[0105]

[0106] Example M5

[0107] The composition and measurement parameters of the liquid crystal composition of Example M5 are shown in Table 7

[0108] Table 7

[0109]

[0110]

[0111] Example M6

[0112] The composition and measurement parameters of the liquid crystal composition of Example M6 are shown in Table 8

[0113] Table 8

[0114]

[0115] Comparative Example C1

[0116] The composition and measurement parameters of the liquid crystal composition of Comparative Example C1 are shown in Table 9

[0117] Table 9

[0118]

[0119]

[0120] The guest-host liquid crystal compositions GH1-GH6 and GHC1 and GHC2 were prepared by mixing the liquid crystal compositions M1-M6 and C1 shown in Examples M1-M6 and Comparative Example C1 with the mixed dye G1, and filled into a horizontally oriented liquid crystal box with a cell thickness of 9 μm to test their performance. The composition and performance parameters of the guest-host liquid crystal compositions GH1-GH6 and GHC1 and GHC2 are shown in Tables 10 to 17.

[0121] Table 10

[0122]

[0123] Table 11

[0124]

[0125] Table 12

[0126]

[0127] Table 13

[0128]

[0129]

[0130] Table 14

[0131]

[0132] Table 15

[0133]

[0134] Table 16

[0135]

[0136] The liquid crystal composition C1 cannot completely dissolve 4.4% mass% of the mixed dye G1. The mixed dye G1 of different mass fractions is added into the liquid crystal composition C1 in groups for dissolution. The complete dissolution of the dye is determined by observing the presence of particles under an optical microscope. Finally, it is concluded that the maximum solubility of the liquid crystal composition C1 for the mixed dye G1 is approximately 2.2%.

[0137] Table 17

[0138]

[0139] From the comparison between the embodiment and the comparative example, it can be seen that the solubility of G1 in the comparative example is much lower than that in the embodiment, which is only half of that in the embodiment. It can be seen that the liquid crystal composition containing more cyano structures has better solubility for dichroic dyes, while the liquid crystal composition containing less cyano structures has poor solubility for dichroic dyes. In addition, the liquid crystal composition provided in the embodiment has an extremely high clearing point and a high dielectric constant, is suitable for a wider operating temperature range and is conducive to reducing the driving voltage.

[0140] The guest-host liquid crystal composition GH1 was selected for thermal stability test. The guest-host liquid crystal composition GH1 was poured into a horizontally aligned liquid crystal cell with a cell thickness of 9 μm. The liquid crystal cell was then placed in an environment of -40°C and 110°C, and its transmittance and color coordinate changes were tested every 7 days. The liquid crystal cell placed at -40°C was observed with an optical microscope to see if there were any particles precipitated. The test results are shown in Table 18 below.

[0141] Table 18

[0142]

[0143] It can be seen from Table 18 that the deviations of the color coordinates and transmittance of the guest-host liquid crystal composition GH1 when stored in low temperature (-40°C) and high temperature (110°C) environments for a long time are less than 2%, showing good high and low temperature stability.

[0144] Although the present invention does not exhaust all liquid crystal compositions claimed for protection, it is foreseeable that, based on the above disclosed embodiments, those skilled in the art can obtain other similar materials in a similar manner by combining their own professional attempts without creative work. Due to limited space, only representative implementations are listed here.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid crystal composition, characterized in that: The liquid crystal composition comprises at least one liquid crystal compound of component I, at least one liquid crystal compound of component II, and at least one liquid crystal compound of component III; The component I is a liquid crystal compound having a general formula I, and the general formula I is as follows: n is 1 or 2; When n is 1, Selected from When n is 2, the components include two Right now appears twice in the component, Each time it occurs, it is independently R1 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups; The component II is a liquid crystal compound having a general formula II, and the general formula II is as follows: R2 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group, and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups, and alkenyloxy groups; X1 and X2 are each independently selected from H or F, and at least one of X1 and X2 is F; The component III is a liquid crystal compound having a general formula III, and the general formula III is as follows: R3 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted with an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

2. A liquid crystal composition according to claim 1, characterized in that: The component I is selected from one or more liquid crystal compounds represented by formulas A1 to A5, wherein the formulas A1 to A5 are as follows: <h2 style=";text-align:left;direction:ltr">A1、<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> A2、<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">A3、<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> A4、<h2 style=";text-align:left;direction:ltr"> A5、 Wherein, R4 is an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

3. A liquid crystal composition according to claim 1, characterized in that: In the liquid crystal composition, the mass content of component I is 30-70%, the mass content of component II is 10-40%, and the mass content of component III is 5-35%.

4. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises non-polar liquid crystal compounds represented by formulas C1 to C3, wherein formulas C1 to C3 are as follows: C1. C2, C3, Wherein, R6 and R6' are each independently selected from an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms or an alkenyloxy group having 2 to 7 carbon atoms; the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

5. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises polar liquid crystal compounds represented by formulae D1 to D16, wherein formulae D1 to D16 are as follows: D1. D2. D3、 D4、 D5、 D6、 D7、 D8、 D9、 D10、 D11、 D12、 D13、 D14、 D15、 D16、 6. A liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises one or more dichroic dyes.

7. A liquid crystal composition according to claim 6, characterized in that: The one or more dichroic dyes are selected from compounds represented by formulas B1 to B16, and formulas B1 to B16 are as follows: B1、 B2、 B3、 B4、 B5、 B6、 B7、 B8、 B9、 B10、 B11、 B12、 B13、 B14、 B15、 B16、 Wherein, R5 and R5' are each independently an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, an alkenyloxy group having 2 to 7 carbon atoms, a halogenated alkyl group having 1 to 7 carbon atoms, a halogenated alkoxy group having 1 to 7 carbon atoms, a halogenated alkenyl group having 2 to 7 carbon atoms, a halogenated alkenyloxy group having 2 to 7 carbon atoms, a cyclopentyl group, or a cyclopentyl group substituted by an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms; and the alkyl group, the alkoxy group, the alkenyl group and the alkenyloxy group are straight-chain or branched alkyl groups, alkoxy groups, alkenyl groups and alkenyloxy groups.

8. The liquid crystal composition according to claim 6, characterized in that: The mass fraction of the dichroic dye is 0.1 to 30%.

9. The liquid crystal composition according to claim 1, characterized in that: The liquid crystal composition further comprises a chiral agent with a mass fraction of 0 to 20%.

10. Use of the liquid crystal composition according to any one of claims 1 to 9 in a light valve, a switchable window, a switchable mirror and a guest-host display.

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