Twist-bend nematic phase liquid crystal dimer material and use thereof, and liquid crystal oblique helicoidal material and use thereof

Abstract

The present invention belongs to the technical field of liquid crystal materials; and specifically relates to a twist-bend nematic phase liquid crystal dimer material and the use thereof, and a liquid crystal oblique helicoidal material and the use thereof. The twist-bend nematic phase liquid crystal dimer material provided by the present invention is selected from at least one of CBnCB, CBnOCB and CBOnOCB, wherein n is a positive integer selected from 3-15. The liquid crystal dimer material of the present invention has a very low bending elastic constant and satisfies the requirement of long-term storage, and the NTB phase state thereof is free of any crystallization when stored at room temperature for 300 days or more. On the basis of the above ultra-stable material properties, the present invention further provides a liquid crystal oblique helicoidal material, wherein the liquid crystal dimer material is used as the core raw material; a conventional nematic phase liquid crystal material and chiral molecules are fused; the phase state temperature interval of the material covers room temperature, i.e. 25°C; and the liquid crystal oblique helicoidal material is extremely stable, is free of crystallization when stored for 400 days or more, has stable physical parameters, and satisfies the requirement for stable and reliable electric-field modulation performance.

Description

A twisted nematic liquid crystal dimer material and its application, a liquid crystal tilted helical material and its application

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 24, 2023, with application number CN202310908656.2 and invention name “A room temperature stable and non-crystallized liquid crystal tilted spiral material and its application”, the entire contents of which are incorporated by reference into this application.

[0002] This application claims priority to the Chinese patent application filed with the Patent Office of China on July 24, 2023, with application number CN202310908652.4 and invention name “A room temperature stable and non-crystallized twisted nematic liquid crystal dimer material and its application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention belongs to the technical field of liquid crystal materials, and in particular relates to a twisted-bend nematic liquid crystal dimer material and its application, and a liquid crystal tilted helical material and its application. Background Art

[0004] Twisted bend nematic liquid crystal (N TB ) is a new type of nematic liquid crystal material discovered in the past decade. It is composed of bent liquid crystal dimer molecules and has a nanoscale periodic spiral structure. It is a photonic material with wide application potential. TB Liquid crystal materials have the advantages of fast response speed, wide viewing angle, low voltage drive, and low power consumption. Therefore, they have broad application prospects in liquid crystal display, optical communication, laser modulators, biosensors and other fields.

[0005] N TB The study of liquid crystal materials began in 2010, and this phase was discovered in various bent liquid crystal dimer compounds containing flexible methylene spacers, such as CB7CB. TB Liquid crystal dimer materials in the liquid crystal phase exhibit extremely low bending elastic constants K 33 , which is very different from conventional long rod-shaped liquid crystal materials. TB Liquid crystal materials have received more and more attention, involving the synthesis, property characterization, theoretical simulation, and application of materials. TB The temperature range of the liquid crystal phase is closely related to its chemical structure and usually only exists at higher temperatures and a narrow temperature range, which greatly limits its implementation in device manufacturing. Ideally, it needs to be stable at room temperature.

[0006] Currently, there are some solutions to reduce the N by designing specific molecular structures, such as introducing S bonds and pyrene-based functional groups.TB The temperature range of the phase, or the rapid cooling process to form glassy N TB However, although the above methods can obtain N at low temperature or room temperature TB However, this state is extremely unstable and will crystallize after being stored for a few hours, so it is still not suitable for practical application.

[0007] Through specific molecular structure design, such as functional modification on the structure of liquid crystal dimer, introduction of some specific functional groups such as sulfide bond, pyrene; changing the symmetry of liquid crystal dimer molecular structure, etc., to optimize N TB The temperature range of the phase state can obtain N in a larger temperature range. TB phase, and even room temperature N TB However, the above molecular design scheme faces the following three major challenges: 1) Although the current materials can reach low temperature or room temperature, the above material system is extremely unstable and the sample will crystallize after being stored for a few hours or days; 2) Molecular design is difficult, the chemical synthesis cycle is long, and purification is difficult; 3) The uncertainty of molecular design is large, and it is impossible or unsatisfactory to obtain N TB phase, even the synthesized molecules cannot form N TB Phase.

[0008] Through some specific processes such as rapid liquid nitrogen refrigeration or specific liquid crystal dimer molecular design, glassy N TB Phase. Depending on the molecular structure, the glass transition temperature of liquid crystal dimers can be at an extremely low temperature close to 0°C or above room temperature. TB The phase state is also extremely unstable, which manifests itself in two aspects: on the one hand, it cannot respond normally to an external electric field, and once an electric field is applied to it or a large temperature change occurs, this glassy N TB There will be structural collapse, from N TB On the other hand, this room temperature N TB The phase state is still not stable for a long period of time and crystallization will occur after a few days of storage.

[0009] N TB One of the most prominent applications of liquid crystal materials is the construction of liquid crystal tilted helical structures, a very promising photonic superstructure that has attracted considerable attention in recent years due to its wide dynamic range reflection band modulation performance driven by low electric fields. The tilted helical structure is a special chiral nematic phase liquid crystal state. When the material system meets the requirements of an unusually low bending elastic constant (K 33<1pN), a tilted spiral structure can be constructed with the help of an external electric field. In the tilted spiral structure, the liquid crystal molecules spontaneously spirally arrange to form a one-dimensional spiral periodic structure along the direction of the electric field, and form a specific tilt angle θ with the direction of the spiral axis, where the spacing of the spiral is called the pitch P. This special molecular assembly behavior allows the tilt angle θ and pitch P in the tilted spiral structure to be reversibly modulated over a wide range according to changes in the electric field intensity, thereby manifesting as spectral modulation within a wide dynamic range controlled by a low electric field. This spectral modulation range can start from the near-ultraviolet band, cover the entire visible light band, and extend to the near-infrared band, with a total spectral modulation range of more than 600nm, and this electric field modulation behavior has almost no spectral distortion. The traditional electric field modulation behavior of the cholesteric phase spiral structure usually faces bottleneck problems such as a narrow spectral modulation range (<50nm), high driving voltage, and spectral distortion. Therefore, the unique electric field modulation property of the tilted helical structure has also inspired a series of innovative photonic technologies based on the tilted helical structure, including spectral filtering, tunable laser microcavities, information encryption, nonlinear optics and dynamically adjustable planar optics applications.

[0010] Currently, the biggest challenge facing industrial applications of tilted helix structures is the room-temperature crystallization instability of the material system. Tilted helix material systems typically consist of three components: 1) the essential liquid crystal dimer material, which provides the ultra-low bend elastic constant necessary to construct the tilted helix; 2) a conventional nematic liquid crystal material, which further modifies the material system's physical parameters, such as the cholesteric phase temperature range and photoelectric anisotropy; and 3) a chiral additive, which provides an initial chiral environment and helical twisting force.

[0011] With N TBLiquid crystal dimer materials with this phase have an ultra-low bending elastic constant due to their unique molecular configuration, which is a necessary condition for the formation of tilted helices. However, the nematic phase temperature range of liquid crystal dimer materials is usually extremely high and the temperature range is extremely narrow. For example, the most typical liquid crystal dimer material CB7CB has a nematic phase between 104 and 117°C, which greatly limits its application scenarios. Although the nematic phase temperature can be lowered and the phase range can be widened through molecular design, it is still a long way from room temperature. In addition, molecular design usually has a long R&D cycle and high R&D risks, and faces difficulties such as new molecule design, synthesis, and purification. On the other hand, by mixing traditional nematic phase liquid crystal materials (such as 5CB liquid crystal, E7 liquid crystal, etc.) with liquid crystal dimer materials, the nematic phase temperature of the material system can be effectively lowered and the phase range can be widened, covering room temperature and maintaining an ultra-low bending elastic constant. Although liquid crystal dimer materials have very good miscibility with traditional nematic phase liquid crystal materials, the material system is very unstable at room temperature and usually crystallizes within a few hours, causing structural collapse. This is mainly due to the instability of liquid crystal dimer materials at low temperatures. Currently, there is still no substantial molecular design or process optimization to solve the above problem.

[0012] Summary of the Invention

[0013] In view of the above shortcomings of the prior art, the present invention aims to provide a twisted nematic phase (N TB ) Liquid crystal dimer materials and their applications, a liquid crystal tilted helical material and its applications.

[0014] In order to achieve the above object, the present invention provides the following technical solutions:

[0015] The first aspect of the present invention provides a room temperature stable and crystallization-free twisted bend nematic liquid crystal dimer material, selected from at least one of CBnCB, CBnOCB and CBOnOCB, where n is a positive integer selected from 3 to 15 (such as 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12);

[0016] The structure of the CBnCB is as follows:

[0017] The structure of the CBnOCB is shown below:

[0018] The structure of the CBOnOCB is as follows:

[0019] Preferably, the room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: 30% to 75% of CB7CB, 15% to 45% of CB9CB and 5% to 25% of CB11CB;

[0020] The structure of the CB7CB is shown below:

[0021] The structure of the CB9CB is as follows:

[0022] The structure of the CB11CB is as follows:

[0023] Preferably, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40% to 60%, CB9CB 20% to 40% and CB11CB 10% to 20%.

[0024] Preferably, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0025] Alternatively, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: 40% of CB7CB, 40% of CB9CB and 20% of CB11CB.

[0026] Preferably, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 50%, CB9CB 35% and CB11CB 15%.

[0027] Alternatively, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: 55% of CB7CB, 30% of CB9CB and 15% of CB11CB.

[0028] A second aspect of the present invention provides a room temperature stable and crystallization-free liquid crystal tilted helical material, which is made of the following components in percentage by weight: 35% to 55% liquid crystal dimer material, 40% to 60% nematic liquid crystal monomer material, and 0.1% to 10% chiral molecules;

[0029] The liquid crystal dimer material is CBnCB, where n is a positive integer selected from 3 to 15 (such as 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12); the structure is as follows:

[0030] Preferably, the nematic liquid crystal monomer material is selected from 5CB, 8CB, 7OCB, E7, TEB300, SLC1717, SLC9023, HTD028200-200;

[0031] The structure of the 5CB is shown below:

[0032] The structure of the 8CB is as follows:

[0033] The structure of the 7OCB is as follows:

[0034] The E7 was purchased from Jiangsu Hecheng, Shijiazhuang Chengzhi Yonghua, Yantai Xianhua and Merck, Germany; the TEB300, SLC1717 and SLC9023 were purchased from Shijiazhuang Chengzhi Yonghua; and the HTD028200-200 was purchased from Jiangsu Hecheng.

[0035] Preferably, the chiral molecule is selected from CB15, R811, S811, R2011, S2011, R1011, S1011, R5011, and S5011.

[0036] Preferably, the structure of CB15 is as follows:

[0037] The structure of R811 is as follows:

[0038] The structure of S811 is as follows:

[0039] The structure of R1011 is as follows:

[0040] The structure of S1011 is as follows:

[0041] The structure of R2011 is as follows:

[0042] The structure of S2011 is as follows:

[0043] The structure of R5011 is as follows:

[0044] The structure of S5011 is as follows:

[0045] The chiral molecules are all purchased commercially, and the suppliers can be selected from Jiangsu Hecheng, Shijiazhuang Chengzhi Yonghua, Yantai Xianhua and Merck of Germany.

[0046] Preferably, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 30% to 75%, CB9CB 15% to 45% and CB11CB 5% to 25%;

[0047] The structure of the CB7CB is shown below:

[0048] The structure of the CB9CB is as follows:

[0049] The structure of the CB11CB is as follows:

[0050] Preferably, the room temperature stable non-crystallized liquid crystal tilted helical material is made of the following components in percentage by weight: 40-50% liquid crystal dimer material, 45-55% nematic phase liquid crystal monomer material and 1-5% chiral molecules.

[0051] Preferably, the room temperature stable and non-crystallized liquid crystal tilted helical material is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic phase liquid crystal monomer material and 3% chiral molecules.

[0052] Preferably, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40% to 60%, CB9CB 20% to 40% and CB11CB 10% to 20%.

[0053] Preferably, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 60%, CB9CB 20% and CB11CB 20%;

[0054] Alternatively, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40%, CB9CB 40% and CB11CB 20%.

[0055] Preferably, the room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 50%, CB9CB 35% and CB11CB 15%;

[0056] Alternatively, the room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is made of the following components in percentage by weight: 55% of CB7CB, 30% of CB9CB and 15% of CB11CB.

[0057] In the present invention, liquid crystal dimer materials can provide the required ultra-low bending elastic constant and inhibit crystallization; nematic liquid crystal monomer materials can reduce the nematic phase temperature range and modify the physical parameters of the material system; chiral molecules can construct an initial chiral environment to form a chiral nematic phase. Based on the difference in the helical twisting force of the chiral molecules and the left-handed and right-handed chirality, specific chiral molecules can be selected and the content of the chiral molecules can be adjusted.

[0058] The third aspect of the present invention provides an application of the room temperature stable and non-crystalline twisted bend nematic liquid crystal dimer material described in the above scheme or the room temperature stable and non-crystalline liquid crystal tilted helical material described in the above scheme in the preparation of display panels and display devices.

[0059] Due to the adoption of the above technical solution, the present invention has the following advantages and beneficial effects:

[0060] The present invention provides a room temperature stable and crystallization-free twisted bend nematic liquid crystal dimer material. The room temperature stable and crystallization-free twisted bend nematic liquid crystal material provided by the present invention has simple monomer components and a simple preparation process. By mixing a variety of liquid crystal dimer materials with different molecular bending degrees and central flexibility in a specific ratio, the supercooling ability of the material system is significantly enhanced by the interaction between molecules and the entanglement of molecular chains, thereby achieving stable, reliable, and crystallization-free N-terminal at room temperature. TB phase, the sample maintains N over a wide temperature range TB phase region, and no crystallization for at least 300 days. TB In-depth research on phase states is of great significance to the development of modern photonics.

[0061] The room temperature stable non-crystallized twisted bend nematic liquid crystal material provided by the present invention can effectively improve the overall stability of the material system according to different dimer component ratios; the room temperature stable non-crystallized twisted bend nematic liquid crystal material has a wide temperature range of N TB Phase, from room temperature to nearly 100 ° C.

[0062] The room temperature stable non-crystallized twisted nematic liquid crystal material provided by the present invention can meet the long-term storage requirements. TB Even after being stored at room temperature for more than 300 days, no crystallization was observed. The material system exhibits excellent stability, far exceeding other material systems.

[0063] The present invention also provides a room temperature stable non-crystallized liquid crystal tilted helical material. The room temperature stable non-crystallized liquid crystal tilted helical material of the present invention has an overall chiral nematic phase temperature range covering room temperature 25°C. The material system is extremely stable and no crystallization occurs even when stored at room temperature for more than one year. The material system has an extremely low bending elastic constant, and its K 33 <0.4pN; the physical parameters of the material system, including the dielectric constant and the elastic constant, remain stable and do not fluctuate with storage. Even after being stored for one year, the physical parameters of the material system of the present invention do not change significantly.

[0064] The room-temperature stable, crystal-free liquid crystal tilted helical material of the present invention exhibits wide dynamic selective reflective modulation under low electric field drive (<2V / μm). Its reflective band modulation extends from 430nm to 1050nm, exceeding 600nm. This wide spectrum modulation under electric field action remains extremely stable. After one year of storage, the reflective spectrum bands corresponding to the electric field strength exhibit a nearly one-to-one correspondence, with no significant differences.

[0065] The nematic phase temperature range of the currently available material system is relatively high, usually existing above 100° C. The nematic phase of the room temperature stable and crystal-free liquid crystal tilted helical material of the present invention covers room temperature.

[0066] Existing material systems are very unstable at room temperature and typically crystallize rapidly within a few hours, leading to structural collapse and complete failure. The room-temperature stable, non-crystallizing liquid crystal tilted helical material of the present invention is extremely stable and does not crystallize even after storage at room temperature for more than one year.

[0067] The room-temperature stable and crystallization-free liquid crystal tilted helical material of the present invention is prepared by mixing a plurality of relatively conventional liquid crystal dimers such as CB7CB, CB9CB, and CB11CB in specific proportions. Through the synergistic interaction between molecules and the complexity of the molecular conformation brought about by the molecular chain entanglement effect, the stability of the material system is effectively improved, thereby inhibiting crystallization.

[0068] The present invention also provides the use of the room-temperature stable, non-crystallized twisted nematic liquid crystal dimer material or the room-temperature stable, non-crystallized liquid crystal tilted helical material described in the above scheme in the preparation of display panels and display devices. This invention resolves the bottleneck that has long restricted the application of tilted helical structures and represents a key technological breakthrough in advancing their application to engineering and even mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0070] FIG1 is a schematic diagram of the molecular structure of liquid crystal dimers CB7CB, CB9CB and CB11CB and their polarized microstructure and phase state during the cooling process;

[0071] FIG2 is a schematic diagram of the time when crystallization occurs after storage at room temperature for samples S4, S5, S6, S7, and S8;

[0072] FIG3 is a schematic diagram of XRD analysis of samples S4, S5, S6, S7 and S8 after storage at room temperature;

[0073] 4 is a schematic diagram of differential scanning calorimetry (DSC) data of samples S4, S5, S6, S7, and S8 when the temperature was lowered from 130° C. at a rate of 5° C. / min;

[0074] FIG5 is a schematic diagram showing the dielectric constant and elastic parameter results of the room temperature stable non-crystallized liquid crystal tilted helical material of the present invention tested at different time stages during storage for one year;

[0075] FIG6 is a schematic diagram showing the reflection spectrum of the room temperature stable non-crystallized liquid crystal tilted helical material sample T-1 of the present invention during a one-year storage period as a function of electric field driving;

[0076] 7 is a schematic diagram of the electric field-driven reflection band of the tilted helical material system constructed by the room temperature stable non-crystallized liquid crystal tilted helical material sample T-1 of the present invention and the sample D-6 prepared in Comparative Example 9;

[0077] FIG8 is a schematic diagram showing the polarizing microscope display results of the room temperature stable non-crystallized liquid crystal tilted helical material of the present invention;

[0078] FIG9 is a schematic diagram showing the crystallization behavior of the conventional unstable inclined helical material comparative example 1 observed with the naked eye and verified with a polarizing microscope. DETAILED DESCRIPTION

[0079] To further illustrate the present invention, the applicant will now provide a detailed description of the present invention with reference to the accompanying drawings and specific embodiments, with the goal of enabling those skilled in the art to clearly understand the present invention. However, the following embodiments should not be construed as limiting the scope of protection of the present invention to any extent.

[0080] For the preparation of CBnCB, CBnOCB and CBOnOCB in the examples of the present invention, please refer to the literature: Liq. Cryst., 2017, 44, 127-146.

[0081] The reagents used in the examples of the present invention are as follows:

[0082] 1,5-bis(4'-cyanobiphenyl)pentane—CB5CB molecular formula:

[0083] 1,7-bis(4'-cyanobiphenyl)heptane—CB7CB Molecular formula:

[0084] 1,9-bis(4'-cyanobiphenyl)nonane—CB9CB Molecular formula:

[0085] 1,11-bis(4-(4'-cyanobiphenyl)undecane)—CB11CB Molecular formula:

[0086] 1-(4-cyanobiphenyl-4'-oxy)-4-(4-cyanobiphenyl-4'-yl)hexane—CB4OCB Molecular formula:

[0087] 1-(4-cyanobiphenyl-4'-oxy)-6-(4-cyanobiphenyl-4'-yl)hexane—CB6OCB Molecular formula:

[0088] 1,3-Bis(4-cyanobiphenyl-4'-oxy)alkane—CBO3OCB Molecular formula:

[0089] The synthetic route of the CBnCB material is as follows:

[0090] Adipoyl chloride and 4-bromobiphenyl were added dropwise to a suspension of aluminum trichloride / dichloromethane and stirred. The reaction mixture was then added to water and shaken with dichloromethane. The remaining aqueous suspension was filtered, and the solid was thoroughly washed with water and recrystallized from toluene. Triethylsilane was added dropwise to α,ω-bis(4'-bromobiphenyl-4-yl)butane and stirred in a solution of trifluoroacetic acid and dichloromethane. The reaction mixture was allowed to reach room temperature and stirred for 48 hours. The white solid was then filtered, washed with water, and recrystallized from toluene. A mixture of α,ω-bis(4'-bromobiphenyl-4-yl)hexane, cuprous cyanide, and dry N-methylpyrrolidone was stirred at 200°C for 4 hours, then cooled to 80°C, and ferric chloride and hydrochloric acid were added. After stirring for an additional 30 minutes, the mixture was allowed to cool overnight, water was added, and the mixture was shaken with dichloromethane. The organic layer was washed with water, dried over CaCl2, and the solvent removed, before being recrystallized from toluene.

[0091] Example 1

[0092] A room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is prepared from the following components in weight percentage: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB. The material is named sample S7.

[0093] During the test, each substance was weighed according to the above ratio, stirred evenly for 2 hours at 130°C to make it uniformly mixed, and then the test was performed. The following examples and comparative examples were all carried out according to this method.

[0094] Example 2

[0095] A room temperature stable and crystallization-free twisted bend nematic liquid crystal dimer material is prepared from the following components in weight percentage: 40% of CB7CB, 40% of CB9CB, and 20% of CB11CB. The material is named sample S8.

[0096] Example 3

[0097] A room temperature stable and crystal-free twisted bend nematic liquid crystal dimer material is prepared from the following components in weight percentage: CB7CB 50%, CB9CB 35% and CB11CB 15%. The material is named sample S9.

[0098] Example 4

[0099] A room temperature stable and crystallization-free twisted bend nematic liquid crystal dimer material is prepared from the following components in weight percentage: 55% of CB7CB, 30% of CB9CB, and 15% of CB11CB. The material is named sample S10.

[0100] Comparative Example 1

[0101] CB7CB was used as a single component and the material was named sample S1.

[0102] Comparative Example 2

[0103] CB9CB was used as a single component and the material was named sample S2.

[0104] Comparative Example 3

[0105] CB11CB was used as a single component and the material was named sample S3.

[0106] Comparative Example 4

[0107] A liquid crystal material is made of the following components in percentage by weight: 60% of CB7CB and 40% of CB9CB. The material is named sample S4.

[0108] Comparative Example 5

[0109] A liquid crystal material is made of the following components in percentage by weight: 60% of CB7CB and 40% of CB11CB. The material is named sample S5.

[0110] Comparative Example 6

[0111] A liquid crystal material is made of the following components in percentage by weight: 60% of CB9CB and 40% of CB11CB. The material is named sample S6.

[0112] Example 5

[0113] A room temperature stable and non-crystallized liquid crystal tilted helical material, designated as sample T-1, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0114] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB, and 20% of CB11CB.

[0115] The nematic liquid crystal monomer material is 5CB.

[0116] The chiral molecule is R811.

[0117] Example 6

[0118] A room temperature stable and non-crystallized liquid crystal tilted helical material, designated as sample T-4, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0119] The liquid crystal dimer material is made of the following components in percentage by weight: 40% of CB7CB, 40% of CB9CB and 20% of CB11CB.

[0120] The nematic liquid crystal monomer material is 5CB.

[0121] The chiral molecule is R811.

[0122] Example 7

[0123] A room temperature stable and non-crystallized liquid crystal tilted helical material, named sample T-7, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0124] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0125] The nematic liquid crystal monomer material is E7.

[0126] The chiral molecule is R811.

[0127] Example 8

[0128] A room temperature stable and non-crystallized liquid crystal tilted helical material, named sample T-8, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0129] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0130] The nematic liquid crystal monomer material is TEB300.

[0131] The chiral molecule is R811.

[0132] Example 9

[0133] A room temperature stable and non-crystallized liquid crystal tilted helical material, named sample T-9, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0134] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0135] The nematic liquid crystal monomer material is SLC1717.

[0136] The chiral molecule is R811.

[0137] Example 10

[0138] A room temperature stable and non-crystallized liquid crystal tilted helical material, named sample T-10, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0139] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0140] The nematic liquid crystal monomer material is HTD028200-200.

[0141] The chiral molecule is R811.

[0142] Example 11

[0143] A room temperature stable and non-crystallized liquid crystal tilted helical material, designated as sample T-11, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0144] The liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB.

[0145] The nematic liquid crystal monomer material is SLC9023.

[0146] The chiral molecule is R811.

[0147] Comparative Example 7

[0148] One material, designated as sample S-1, is made of the following components in weight percentages: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0149] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 100%, CB9CB 0% and CB11CB 0%.

[0150] The nematic liquid crystal monomer material is 5CB.

[0151] The chiral molecule is R811.

[0152] Comparative Example 8

[0153] One material, designated as sample S-2, is made of the following components in weight percentages: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0154] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 0%, CB9CB 100% and CB11CB 0%.

[0155] The nematic liquid crystal monomer material is 5CB.

[0156] The chiral molecule is R811.

[0157] Comparative Example 9

[0158] One material, designated as sample S-2, is made of the following components in weight percentages: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0159] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 0%, CB9CB 0% and CB11CB 100%.

[0160] The nematic liquid crystal monomer material is 5CB.

[0161] The chiral molecule is R811.

[0162] Comparative Example 10

[0163] One material, designated as sample D-1, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0164] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 80%, CB9CB 20% and CB11CB 0%.

[0165] The nematic liquid crystal monomer material is 5CB.

[0166] The chiral molecule is R811.

[0167] Comparative Example 11

[0168] One material, designated as sample D-2, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0169] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 80%, CB9CB 0% and CB11CB 20%.

[0170] The nematic liquid crystal monomer material is 5CB.

[0171] The chiral molecule is R811.

[0172] Comparative Example 12

[0173] One material, designated as sample D-3, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0174] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 0%, CB9CB 80% and CB11CB 20%.

[0175] The nematic liquid crystal monomer material is 5CB.

[0176] The chiral molecule is R811.

[0177] Comparative Example 13

[0178] One material, designated as sample D-4, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0179] The liquid crystal dimer material is made of the following components in percentage by mass: CB7CB 0%, CB9CB 20%, and CB11CB 80%.

[0180] The nematic liquid crystal monomer material is 5CB.

[0181] The chiral molecule is R811.

[0182] Comparative Example 14

[0183] One material, designated as sample D-5, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0184] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 20%, CB9CB 0% and CB11CB 80%.

[0185] The nematic liquid crystal monomer material is 5CB.

[0186] The chiral molecule is R811.

[0187] Comparative Example 15

[0188] One material, designated as sample D-6, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0189] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 60%, CB9CB 40% and CB11CB 0%.

[0190] The nematic liquid crystal monomer material is 5CB.

[0191] The chiral molecule is R811.

[0192] Comparative Example 16

[0193] One material, designated as sample D-7, is made of the following components in weight percentages: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0194] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 60%, CB9CB 0% and CB11CB 40%.

[0195] The nematic liquid crystal monomer material is 5CB.

[0196] The chiral molecule is R811.

[0197] Comparative Example 17

[0198] One material, designated as sample D-8, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0199] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 0%, CB9CB 60% and CB11CB 40%.

[0200] The nematic liquid crystal monomer material is 5CB.

[0201] The chiral molecule is R811.

[0202] Comparative Example 18

[0203] One material, designated as sample D-9, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0204] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 0%, CB9CB 40% and CB11CB 60%.

[0205] The nematic liquid crystal monomer material is 5CB.

[0206] The chiral molecule is R811.

[0207] Comparative Example 19

[0208] One material, designated as sample D-10, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0209] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40%, CB9CB 60% and CB11CB 0%.

[0210] The nematic liquid crystal monomer material is 5CB.

[0211] The chiral molecule is R811.

[0212] Comparative Example 20

[0213] One material, designated as sample D-11, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0214] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40%, CB9CB 0% and CB11CB 60%.

[0215] The nematic liquid crystal monomer material is 5CB.

[0216] The chiral molecule is R811.

[0217] Comparative Example 21

[0218] A material, designated as sample T-2, is made of the following components in weight percentages: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0219] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 20%, CB9CB 60% and CB11CB 20%.

[0220] The nematic liquid crystal monomer material is 5CB.

[0221] The chiral molecule is R811.

[0222] Comparative Example 22

[0223] One material, designated as sample T-3, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0224] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 20%, CB9CB 20% and CB11CB 60%.

[0225] The nematic liquid crystal monomer material is 5CB.

[0226] The chiral molecule is R811.

[0227] Comparative Example 23

[0228] One material, designated as sample T-5, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0229] The liquid crystal dimer material is made of the following components in percentage by weight: 40% of CB7CB, 20% of CB9CB and 40% of CB11CB.

[0230] The nematic liquid crystal monomer material is 5CB.

[0231] The chiral molecule is R811.

[0232] Comparative Example 24

[0233] One material, designated as sample T-6, is made of the following components in percentage by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0234] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 20%, CB9CB 40% and CB11CB 40%.

[0235] The nematic liquid crystal monomer material is 5CB.

[0236] The chiral molecule is R811.

[0237] Comparative Example 25

[0238] A room temperature stable and non-crystallized liquid crystal tilted helical material, designated as sample T-12, is made of the following components by weight: 45% liquid crystal dimer material, 52% nematic liquid crystal monomer material, and 3% chiral molecule;

[0239] The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 80%, CB9CB 10% and CB11CB 10%.

[0240] The nematic liquid crystal monomer material is 5CB.

[0241] The chiral molecule is R811.

[0242] The three groups of samples S1, S2 and S3 were heated to 130°C to melt them into liquid state. At this temperature, they were poured into a liquid crystal cell with surface parallel alignment (size: 15*18mm). 2, thickness 12μm), placed in a precision temperature-controlled hot stage, slowly cooled at a rate of 3℃ / min, and observed its phase transition. The results are shown in Figure 1. Figure 1 is a schematic diagram of the molecular structure of CB7CB, CB9CB and CB11CB and their polarized microtexture and phase state during the cooling process. For sample S1CB7CB, as the temperature decreases, it transforms from liquid to nematic phase (N phase) at 117℃, and from N phase to twisted nematic phase (N phase) at 104℃. TB ). In the N phase, the polarization texture appears as a uniform color. TB In the phase, a rope-like polarization texture is presented. TB The phase state can be maintained up to room temperature 25℃, which is supercooling. TB It is very unstable and will crystallize in about 2 hours. Similar results are also seen in samples S2CB9CB and S3CB11CB. Among them, sample S2 will crystallize at 40℃, while sample S3 will crystallize directly at 80℃. Therefore, the above three samples can show that for general liquid crystal dimer materials, it is usually impossible to obtain room temperature N TB Phase, or its N TB The phase state is extremely unstable and crystallization is likely to occur.

[0243] The three liquid crystal dimer materials CB7CB, CB9CB and CB11CB were weighed according to the proportions of sample S4, sample S5, sample S6, sample S7, sample S8, sample S9 and sample S10 and placed in a sample bottle for mixing. A magnetic stirrer was added to the sample bottle and the sample was stirred evenly at 130°C for 2 hours to make it uniformly mixed. At this temperature, it was poured into a liquid crystal cell with a surface parallel alignment (size 15*18mm) 2 , thickness 12μm), placed in a precision temperature-controlled hot stage, slowly cooled at a rate of 3℃ / min, and observed its phase transition. The phase transition of samples S4, S5, S6, S7, and S8 is very similar to that of samples S1, S2, and S3. They transform from liquid to conventional N phase at around 120℃, and from N phase to N at around 105℃. TB Phase. N of sample S4, sample S5, sample S6, sample S7 and sample S8 TB Both phases can be supercooled to room temperature 25°C.

[0244] The N content of the material was characterized by polarizing microscope (POM) and X-ray diffraction (XRD). TB Temperature range of phase state and room temperature stability. Samples S4, S5, S6, S7 and S8 were stored at room temperature and their stability and crystallization were monitored by POM.TB The phase state can be confirmed by the images measured by polarizing microscope. The results are shown in Figure 2, which is a schematic diagram of the crystallization time of samples S4, S5, S6, S7 and S8 after storage at room temperature. As can be seen from the figure, the first picture on the left in Figure 2 is the initial state of samples S4 to S8 at room temperature. The molecules are arranged in a rope-like shape. This picture proves that N TB In the initial state, each sample is supercooled N at room temperature 25℃. TB Phase, POM exhibits a rope-like texture. However, the crystallization stability of the above samples is closely related to the material composition. For example, sample S4 crystallized on the 5th day; sample S5 crystallized on the 17th day; and sample S6 was very unstable, crystallizing on the first day. Samples S7 and S8, on the other hand, demonstrated astonishing stability. Even after storage for over 300 days, no crystallization occurred, and their polarized microscopy images remained unchanged from their initial state, demonstrating their extremely strong stability.

[0245] In order to further confirm the stability of the above material system, the present invention also used the XRD method to analyze the above sample S4, sample S5, sample S6, sample S7 and sample S8. The results are shown in Figure 3, which is a schematic diagram of the XRD analysis of sample S4, sample S5, sample S6, sample S7 and sample S8 after storage at room temperature. First, the XRD analysis was performed on the sample after it was stored for 10 days. At this time, sample S4 and sample S6 had already crystallized, so their XRD results showed multiple peaks, indicating the structure of the crystal; while at this time, sample S5 had not crystallized and was in a supercooled state N TB Phase state, therefore, no crystallization peak was observed in the XRD results. Samples S7 and S8 have the characteristics of stable non-crystallization. After storage for 180 days, XRD analysis was performed on them. It can be seen that no crystallization peak appeared, proving that the samples are still in the supercooled N TB Phase.

[0246] The results of the differential scanning calorimeter DSC data are shown in Figure 4, which is a schematic diagram of the differential scanning calorimeter analysis (DSC) data of sample S4, sample S5, sample S6, sample S7 and sample S8 when the temperature is cooled from 130°C at a rate of 5°C / min. Looking from right to left in the figure, these material systems have a peak at around 120 degrees and around 100 degrees respectively. The appearance of peaks on the curve proves that the material has undergone a phase change. Therefore, in the process of cooling these samples from high temperature, they transform from liquid (Iso) to nematic phase (N) at about 120°C and transform to twisted nematic phase (N) at about 100°C. TB ). When the temperature is continued to be lowered to room temperature, no other peaks are found, which proves that below about 100℃, the material is in N TBPhase.

[0247] The comparative experimental results of the crystallization stability of the material systems prepared in Examples 5 to 6 and Comparative Examples 7 to 19 are shown in Table 1:

[0248] The sample preparation and crystallization stability test experimental steps are as follows: First, all the above samples were stirred at 130℃ for 2 hours and poured into a commercial liquid crystal test cell. The liquid crystal cell consists of two pieces of transparent glass coated with ITO electrodes and has a size of 18×15mm. 2 , with an internal spacing of 12 μm. The sample was then slowly cooled to room temperature (25°C) at a rate of 5°C / min. To eliminate potential energy within the material, a square wave electric field signal with a voltage of 10 V and a frequency of 1 kHz was applied to the sample for 10 minutes. The sample was then stored in a constant temperature and humidity chamber (25°C, 50%), and its crystallization was observed daily.

[0249] The crystallization time of a sample is defined as the time interval from sample preparation to the moment crystallization is first observed. Crystallization can be roughly assessed visually and verified using a polarizing microscope. Figure 9 shows a schematic diagram of visual observation and polarizing microscope verification. The figures show a photograph of a sample undergoing crystallization and its appearance under a polarizing microscope. Uncrystallized areas exhibit a relatively uniform texture. Once crystallization begins, a distinct crystalline structure forms, such as the dendritic crystals shown in the figure.

[0250] Table 1 Comparative experimental results of crystallization stability of material systems prepared in Examples 5 to 6 and Comparative Examples 7 to 19

[0251] As shown in Table 1, when the mass percentage of the nematic liquid crystal monomer material reaches 52%, the material system exhibits a chiral nematic phase at room temperature (25°C). Depending on the composition and content of the liquid crystal dimer material CBnCB in the material system, the material system exhibits different crystallization times. When the material ratios described in this invention are met, the system exhibits ultra-stable crystallization stability.

[0252] The data in Table 1 demonstrates that when the material system contains only a single liquid crystal dimer material, CBnCB, as in Comparative Examples 7-9, the material system is highly unstable, crystallizing after only a few hours (Samples S-1, S-2, and S-3). When the material system contains two liquid crystal dimer materials, CBnCB, the stability of the material system improves, as in Comparative Examples 10-20. The sample prepared in Comparative Example 15 is the best, maintaining 20 days without crystallization. However, the system's crystallization stability is closely related to the CBnCB content, and most material components still face the problem of poor stability. When the material system contains three liquid crystal dimer materials, CBnCB, the stability of the material system is significantly improved. Samples T-1 prepared in Example 5 and T-4 prepared in Example 6 remained crystallized for 400 days, demonstrating significantly enhanced stability. Comparative Examples 21, 22, and 25 exhibited crystallization on the 38th, 4th, and 5th days, respectively, due to the high concentration of a single CBnCB in the system. This high concentration results in material systems (S-1, S-2, and S-3) with stability approaching that of a single dimer, which is extremely unstable and prone to crystallization. Comparative Examples 23 and 24 crystallized on days 200 and 120, respectively, likely due to the complex intermolecular interactions that were insufficient to establish an optimal equilibrium to prevent crystallization. Therefore, the percentage and ratio of the three liquid crystal dimer materials in the present invention are crucial to their crystallization behavior.

[0253] The enhanced crystallization stability is due to the interaction between multiple liquid crystal dimer materials and is not limited to the nematic liquid crystal monomer materials used with them. Even when the nematic liquid crystal monomer material 5CB in material sample T-1 is replaced with other nematic liquid crystal monomer materials, this strong crystallization stability remains unchanged. The specific results are shown in Table 2 below:

[0254] Table 2 Crystallization stability of liquid crystal tilted helical materials prepared in Examples 5, 7 to 11

[0255] The room temperature stable non-crystallized liquid crystal tilted helical material of the present invention has long-term stability of physical parameters while maintaining ultra-high crystal stability. Sample T-1 prepared in Example 5 was filled into a commercial liquid crystal cell (size: 15*18mm) containing an ITO electrode. 2 , thickness 12 μm), the dielectric constant (parallel dielectric ε) was measured by capacitance-voltage method. ∥ , vertical dielectric ε ⊥ and relative dielectric constant Δε) and splay elastic parameter K 11 and bending elastic parameter K 33. This method induces the liquid crystal to shift from a planar arrangement to a vertical arrangement by applying an AC signal with a frequency of 1kHz. The capacitance of the sample is monitored as a function of the applied voltage. The external applied voltage varies from 0.1V to 8.5V, and the interval between voltage changes is 30s. According to the theoretical fitting test of the dependence of capacitance on voltage, the relative dielectric constant and elastic parameters can be extracted. The above-mentioned tests on dielectric and elastic parameters are completed using a commercial liquid crystal comprehensive parameter tester (ALCT-IV1, INSTEC, USA). The results are shown in Figure 5, which is a schematic diagram of the dielectric constant and elastic parameter results of the room temperature stable and crystallization-free liquid crystal tilted helical material of the present invention tested at different time stages during a storage period of 1 year. Among them, the ε of the material system ∥ and ε ⊥ The relative dielectric constants are approximately 14.6 and 5.7, respectively, and the relative dielectric constant Δε is approximately 8.9, indicating a positive liquid crystal. The molecules can be aligned along the electric field under the action of the electric field, satisfying one of the conditions for the construction of a tilted helix. Material system K 11 The most important thing is that the material prepared by the present invention satisfies the ultra-low bending elastic constant, K 33 =0.3pN. This ultra-low bending elastic constant is essential for constructing the tilted helix and plays a key role in the subsequent wide dynamic range modulation of the tilted helix structure's reflective color. Furthermore, even after a year of storage, the measured physical parameters show almost no noticeable change, further confirming the material system's ultra-high stability.

[0256] Furthermore, to verify the stability of the room-temperature stable, crystallization-free liquid crystal tilted helical material sample T-1 of the present invention, the electric field-driven reflection band modulation performance of the constructed tilted helical structure was analyzed. The reflectance spectrum of sample T-1 was tested over a one-year storage cycle, with the results shown in Figure 6. Figure 6 is a schematic diagram of the reflectance spectrum of the room-temperature stable, crystallization-free liquid crystal tilted helical material sample T-1 of the present invention over a one-year storage cycle, as a function of electric field. By applying an external electric field to construct the tilted helical structure, increasing the external electric field strength from 0.52 to 1.33 V / μm resulted in a compression of the pitch P and tilt angle θ of the tilted helical structure, accompanied by a sequential shift in reflected color to bright red, orange, green, cyan, and dark blue, corresponding to a blue shift in the reflectance spectrum. The reflectance spectrum can be reversibly and repeatedly manipulated over a wide spectral range of 450 nm to 1050 nm. Even after more than a year of storage and testing, the sample remained crystallized. More encouragingly, the reflectance spectra corresponding to the corresponding electric field strengths showed no significant changes, confirming the robust stability of the tilted helical structure described herein.

[0257] As a comparison, the electric field-driven reflection band of the tilted spiral material system constructed by the unstable material system (such as sample D-6 prepared in comparative example 15) was tested, and the results are shown in Figure 7. Figure 7 is a schematic diagram of the electric field-driven reflection band of the tilted spiral material system constructed by the room temperature stable non-crystallized liquid crystal tilted spiral material sample T-1 and the sample D-6 prepared in comparative example 15 of the present invention. As can be seen from the figure, the room temperature stable non-crystallized liquid crystal tilted spiral material sample T-1 of the present invention does not have any crystallization even after being stored for 400 days, and no matter at any time point during the storage period, the reflection band modulation corresponding to the electric field is tested, whether it is the corresponding relationship between the electric field and the reflection band position, or the overall modulatable spectral range, there is no obvious change. As a comparison, the unstable sample sample D-6 prepared in comparative example 15 began to crystallize on the 20th day. Once crystallized, the reflection band modulation performance corresponding to its electric field rapidly degraded. It is manifested as an offset of the electric field-reflection band position and a reduction in the overall reflection spectrum modulation range. This is because after the liquid crystal dimer material in the material system crystallizes and precipitates, the bending elastic properties of the material system gradually deteriorate.

[0258] The room-temperature stable, crystal-free liquid crystal tilted helical material of the present invention can form a liquid crystal tilted helical structure. This unique helical structure forms under electric field drive. Under electric field drive, the corresponding reflectance spectrum changes with the electric field intensity, exhibiting tunability over a wide dynamic range (450 to 1050 nm). Therefore, the reflectance spectrum data in Figures 6 and 7 confirm the presence of the liquid crystal tilted helical structure.

[0259] To further illustrate the above issues, the following polarizing microscopy data are provided. The results are shown in Figure 8, which is a schematic diagram of the polarizing microscopy results of the room-temperature stable, crystallization-free liquid crystal tilted helical material of the present invention. When no electric field is applied to the room-temperature stable, crystallization-free liquid crystal tilted helical material of the present invention, the material system exhibits a planar helical structure of a traditional cholesteric liquid crystal, with almost no apparent specific reflection spectral information. When an electric field is applied, the material transforms from a planar helical structure to a tilted helical structure. The pitch and tilt angle of the tilted helical structure change with varying electric field strengths, resulting in specific reflection colors (red-green-blue) and specific reflection spectral positions.

[0260] Although the embodiments of the present invention have been shown and described and the present invention has been described in detail, they are only some of the embodiments of the present invention, rather than all of the embodiments. For those skilled in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and other embodiments can be obtained without creativity. These embodiments all fall within the scope of protection of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A room temperature stable non-crystallized twisted nematic liquid crystal dimer material, characterized in that: At least one selected from CBnCB, CBnOCB and CBOnOCB, wherein n is selected from a positive integer from 3 to 15; The structure of the CBnCB is as follows: The structure of the CBnOCB is as follows: The structure of the CBOnOCB is as follows:

2. The room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material according to claim 1, characterized in that: The room temperature stable non-crystallized twisted nematic phase liquid crystal dimer material is made of the following components in percentage by weight: 30% to 75% of CB7CB, 15% to 45% of CB9CB and 5% to 25% of CB11CB; The structure of the CB7CB is as follows: The structure of the CB9CB is as follows: The structure of the CB11CB is as follows:

3. The room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material according to claim 2, characterized in that: The room temperature stable non-crystallized twisted nematic phase liquid crystal dimer material is made of the following components in percentage by weight: 40% to 60% of CB7CB, 20% to 40% of CB9CB and 10% to 20% of CB11CB.

4. The room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material according to claim 2, characterized in that: The room temperature stable non-crystallized twisted nematic phase liquid crystal dimer material is made of the following components in percentage by weight: 60% of CB7CB, 20% of CB9CB and 20% of CB11CB; Alternatively, the room temperature stable non-crystallized twisted nematic liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40%, CB9CB 40% and CB11CB 20%.

5. The room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material according to claim 2, characterized in that: The room temperature stable non-crystallized twisted nematic phase liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 50%, CB9CB 35% and CB11CB 15%; Alternatively, the room temperature stable non-crystallized twisted nematic liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 55%, CB9CB 30% and CB11CB 15%.

6. A room temperature stable non-crystallized liquid crystal tilted helical material, characterized in that: It is made of the following components in percentage by mass: 35% to 55% of liquid crystal dimer material, 40% to 60% of nematic phase liquid crystal monomer material and 0.1% to 10% of chiral molecules; The liquid crystal dimer material is CBnCB, where n is a positive integer selected from 3 to 15; the structure is as follows:

7. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 6, characterized in that: The nematic liquid crystal monomer material is selected from 5CB, 8CB, 7OCB, E7, TEB300, SLC1717, SLC9023, and HTD028200-200.

8. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 6, characterized in that: The chiral molecule is selected from CB15, R811, S811, R2011, S2011, R1011, S1011, R5011, and S5011.

9. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 6, characterized in that: The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 30% to 75%, CB9CB 15% to 45% and CB11CB 5% to 25%; The structure of the CB7CB is as follows: The structure of the CB9CB is as follows: The structure of the CB11CB is as follows:

10. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 6, characterized in that: The room temperature stable non-crystallized liquid crystal tilted helical material is made of the following components in percentage by mass: 40-50% of liquid crystal dimer material, 45-55% of nematic phase liquid crystal monomer material and 1-5% of chiral molecules.

11. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 10, characterized in that: The room temperature stable non-crystallized liquid crystal tilted helical material is made of the following components in percentage by mass: 45% of liquid crystal dimer material, 52% of nematic phase liquid crystal monomer material and 3% of chiral molecules.

12. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 10, characterized in that: The liquid crystal dimer material is made of the following components in percentage by mass: 40% to 60% of CB7CB, 20% to 40% of CB9CB and 10% to 20% of CB11CB.

13. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 12, characterized in that: The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 60%, CB9CB 20% and CB11CB 20%; Alternatively, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 40%, CB9CB 40% and CB11CB 20%.

14. The room temperature stable non-crystallized liquid crystal tilted helical material according to claim 12, characterized in that: The liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 50%, CB9CB 35% and CB11CB 15%; Alternatively, the liquid crystal dimer material is made of the following components in percentage by weight: CB7CB 55%, CB9CB 30% and CB11CB 15%.

15. Use of the room temperature stable non-crystallized twisted bend nematic liquid crystal dimer material as claimed in any one of claims 1 to 5 or the room temperature stable non-crystallized liquid crystal tilted helical material as claimed in any one of claims 6 to 14 in the preparation of display panels and display devices.

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