Method for curing and changing reflection color of cholesteric liquid crystal and liquid crystal monomer thereof

Abstract

The application discloses a curing and reflection color changing method of cholesteric liquid crystal and a liquid crystal monomer thereof. The polymerizable chiral liquid crystal monomer suitable for the method has a structure shown in formula 1 or formula 2 and is used in combination with a specific non-chiral liquid crystal monomer. The application realizes efficient curing of the cholesteric liquid crystal by co-assembling the chiral monomer and the non-chiral monomer and then performing heat curing treatment at 100-180 DEG C without adding an initiator and ultraviolet light. Meanwhile, the color of the cholesteric liquid crystal can be flexibly changed from red to cyan in the visible light region by changing the heat curing temperature, and the internal components of the material need not be changed. The technical scheme provided by the application has the advantages of simple preparation, low cost and high stability, the prepared cured cholesteric liquid crystal material has excellent circularly polarized light conversion performance, the absolute value of an emission asymmetry factor can reach more than 1.5, and the material can be widely applied in circularly polarized light devices, optical anti-counterfeiting and optical display fields.

Description

Technical Field

[0001] This invention relates to a method for curing and recoloring cholesteric liquid crystals and its reflective color, as well as the liquid crystal monomers thereof, belonging to the technical field of cholesteric liquid crystals and circularly polarized light emission. Background Technology

[0002] Circularly polarized light, due to its close resemblance to natural light and its chiral information, holds promise for applications in various fields. To achieve the generation of circularly polarized light, the academic community has developed a large number of organic CPL materials. However, these materials typically exhibit low luminescence asymmetry factors (…). g lum =10 -3 ~10 -1 Furthermore, chiral separation significantly increases manufacturing costs. These performance and cost limitations continue to hinder the practical application of organic circularly polarized luminescent materials.

[0003] To address the issue of low asymmetry factors, cholesteric liquid crystals (CLCs) have been developed and are increasingly being applied in the generation of circularly polarized light. However, most reported CLCs exhibit flow dynamics, necessitating consideration of encapsulation and subsequent leakage issues in practical applications. To address this, photocuring methods using ultraviolet light have emerged. However, such photocuring methods struggle to alter the reflected color of CLCs through simple changes in curing conditions; color changes typically require altering the component ratios within the liquid crystal. Furthermore, photocuring usually necessitates the addition of additional initiator components, which can disrupt the cholesteric phase structure and negatively impact the final circularly polarized light generation results. Therefore, achieving the curing and color modification of cholesteric phases through a curing method that does not require initiators, ultraviolet light, or alteration of internal components is of significant importance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for achieving efficient curing of cholesteric liquid crystals and flexible control of reflective color without the need for external initiators, ultraviolet light irradiation, or changes in the internal composition of the material. At the same time, it provides a novel polymerizable chiral liquid crystal monomer suitable for this scheme and its composition with non-chiral monomers.

[0005] This invention aims to overcome the shortcomings of existing cholesteric liquid crystal materials, such as complex curing processes, difficulty in controlling reflected color, and low conversion efficiency of circularly polarized light. It provides a curable cholesteric liquid crystal material that is easy to operate, low in cost, highly stable, and has an absolute value of luminescence asymmetry factor of more than 1.5, as well as its preparation method and applications.

[0006] The present invention provides a polymerizable chiral liquid crystal monomer compound, the structural formula of which is shown in Formula 1 or Formula 2:

[0007] Formula 1

[0008] Formula 2 Wherein, R represents one or more achiral aromatic rings, achiral fused aromatic rings, or achiral unbranched alkyl chains of different lengths, specifically selected from any one of the following groups: benzene, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, naphthidine, phenanthridine, imidazole, quinoline, isoquinoline, 1,3,5-triazine, pyrimidine, benzophenone, cyanobenzene, triarylborone, diphenyl sulfone, methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, or derivatives of any substitution of the above groups; R * It is selected from any one of the following chiral groups: cholesterol, diosgenin, ergosterol, stigmasterol, rosin acid, dehydrorosin acid, ambroxol, cedrol, menthol, citronellol, α-terpineol, mandelic acid, tartaric acid, chiral α-amino acid, chiral β-amino acid, chiral alkyl chain, chiral polypeptide group, or derivatives of the above groups with arbitrary substitution.

[0009] The chiral liquid crystal framework material provided by this invention is preferably any one of the following structures:

[0010]

[0011] The present invention also provides a method for preparing the chiral liquid crystal monomer compound, comprising the following steps S1-S3 or S4: S1, the compound shown in formula A1 and the compound shown in formula A2 undergo an etherification reaction, followed by a saponification reaction to obtain the compound shown in formula B;

[0012] The definition of R in equation B is the same as in equation 1; S2. The compound shown in formula B undergoes an esterification reaction with acryloyl chloride to obtain the compound shown in formula C.

[0013] S3. The compound shown in formula C and the compound shown in formula D undergo an esterification reaction to obtain the compound shown in formula 1 in claim 1.

[0014] In formula C, R * The definition is the same as in Equation 1 or Equation 2; The compounds shown in S4 and D undergo esterification with acryloyl chloride to obtain the target compound.

[0015] In step S1, the etherification reaction is carried out in the presence of sodium hydroxide and sodium iodide. The reaction solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 2-butanone, acetonitrile, 1,4-dioxane, and tetrahydrofuran. The reaction temperature is 30-100°C and the reaction time is 24-48 hours. In step S1, the molar ratio of the compound shown in formula A1 to the compound shown in formula A2 is 1-2:1; The molar ratio of sodium hydroxide to the compound shown in formula A2 is 1-2:1; The molar ratio of sodium iodide to the compound shown in formula A2 is 1-2:1; In step S2, the esterification reaction is carried out in the presence of N,N-dimethylaniline, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-24 hours. The molar ratio of the acryloyl chloride to the compound shown in formula B is 1-2:1; The molar ratio of N,N-dimethylaniline to the compound shown in formula B is 1-2:1; In step S3, the esterification reaction is carried out in the presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-100 hours. The molar ratio of the compound shown in formula D to the compound shown in formula C can be 1-2:1; The molar ratio of the N,N'-dicyclohexylcarbodiimide to the compound shown in formula C can be 1-2:1; The molar ratio of the 4-dimethylaminopyridine to the compound shown in formula C can be 0.01-0.2:1; In step S4, the esterification reaction is carried out in the presence of N,N-dimethylaniline, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-24 hours.

[0016] The present invention also provides a non-chiral liquid crystal monomer compound, the structural formula of which is shown in Formula 3:

[0017] Formula 3 In the formula, R represents one or more achiral aromatic rings, achiral fused aromatic rings, or achiral unbranched alkyl chains of different lengths, selected from any of the following groups: benzene, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, naphthidine, phenanthridine, imidazole, quinoline, isoquinoline, 1,3,5-triazine, pyrimidine, benzophenone, cyanobenzene, triarylborone, diphenyl sulfone, methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, or derivatives of any substitution of the above groups.

[0018] The non-chiral liquid crystal monomer of the present invention is preferably any one of the following structures:

[0019] The preparation method of the non-chiral liquid crystal monomer compound of the present invention includes the following steps: The compound shown in Formula C was esterified with p-diphenol to obtain the compound shown in Formula 3. Furthermore, the esterification reaction is carried out in the presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine; Furthermore, the molar ratio of the compound shown in Formula C to the p-diphenol is 2-3:1; Furthermore, the molar ratio of the N,N'-dicyclohexylcarbodiimide to the compound shown in formula C is 2-3:1; Furthermore, the molar ratio of the 4-dimethylaminopyridine to the compound shown in formula C can be 0.01-0.2:1; Furthermore, the esterification reaction is carried out in an organic solvent selected from at least one of the following: 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane; Furthermore, the esterification reaction is carried out at a temperature of 0-90 °C for 3-100 hours.

[0020] Furthermore, the present invention provides a method for curing cholesteric liquid crystal, comprising the following steps: The polymerizable chiral liquid crystal monomer compound is mixed with the non-chiral liquid crystal monomer compound to obtain a co-assembled system; The co-assembled system is heated to a molten state, then encapsulated in a container, and thermosetting at a temperature of 100-180°C to obtain a cured cholesteric liquid crystal material.

[0021] Preferably, the mass ratio of the polymerizable chiral liquid crystal monomer compound to the non-chiral liquid crystal monomer compound is 50:30-70, more preferably 50:50; And / or, the temperature of the thermosetting treatment is 120-150°C and the time is 30-360 minutes, preferably 120 minutes.

[0022] Furthermore, the present invention provides a method for recoloring the reflective color of cholesteric liquid crystals, comprising the following steps: The polymerizable chiral liquid crystal monomer compound is mixed with the non-chiral liquid crystal monomer compound to obtain a co-assembled system; The co-assembled system is heated to a molten state and then encapsulated in a container. By performing thermosetting treatment at different thermosetting temperatures, cured cholesteric liquid crystal materials with different reflective colors are obtained; the thermosetting temperature range is 100-180℃. Preferably, the thermosetting temperature is selected from 120℃, 130℃, 140℃ or 150℃. By selecting different thermosetting temperatures, cholesteric liquid crystal materials with different reflective colors in the range of cyan to red can be obtained.

[0023] Preferably, the preparation of the co-assembled system includes the following steps: The polymerizable chiral liquid crystal monomer compound and the non-chiral liquid crystal monomer compound are dissolved in an organic solvent, ultrasonically treated, and then dried on a hot stage at 25-180°C to obtain the co-assembled system. Preferably, the organic solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, and the ultrasonic treatment time is 1-60 minutes.

[0024] Preferably, the mass ratio of the compound shown in Formula 1 or Formula 2 to the compound shown in Formula 3 can be 50:30-70, specifically 50:50. Preferably, the co-assembled system is obtained by dissolving, sonicating, and drying on a hot table after mixing; The solvent for dissolution can be at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, specifically dichloromethane; The ultrasound session can last from 1 to 60 minutes, but can be as short as 10 minutes. The heating temperature of the hot plate can be 25-180 ℃, specifically 70 ℃.

[0025] The method of this invention has the advantages of simple preparation, low cost, high stability, and strong circular polarization conversion performance (the emission asymmetry factor can reach above 1.5). Furthermore, this method can achieve flexible color change from red to cyan in the visible light region without altering the internal composition of the material.

[0026] The present invention has the following advantages: The raw materials required for the preparation of the compounds of this invention are low-cost and can be completed with only simple conversion, resulting in low cost.

[0027] The reaction process of this invention does not involve racemization, thus avoiding the subsequent chiral resolution process.

[0028] The curing method developed in this invention requires no additional initiator or ultraviolet light, and is simple and convenient to operate.

[0029] The curing method developed in this invention can achieve effective cholesteric phase reflectance color change without changing the internal components of the system.

[0030] The prepared cholesteric liquid crystal material can convert red-cyan light into circularly polarized light with a high asymmetry factor. Attached Figure Description

[0031] Figure 1 This is the 1H NMR spectrum of the compound represented by Formula VIII of this invention.

[0032] Figure 2 This is the carbon NMR spectrum of the compound represented by formula VIII of this invention.

[0033] Figure 3 The above is the 1H NMR spectrum of the compound represented by Formula I of this invention.

[0034] Figure 4 This is the carbon NMR spectrum of the compound represented by Formula I of this invention.

[0035] Figure 5 The transmission spectrum of the liquid crystal prepared in Example 11 of the present invention and the asymmetry factor of the circularly polarized light generated by light of different wavelengths passing through the liquid crystal are shown.

[0036] Figure 6 The transmission spectrum of the liquid crystal prepared in Example 12 of the present invention and the asymmetry factor of the circularly polarized light generated when light of different wavelengths passes through the liquid crystal are shown.

[0037] Figure 7 The transmission spectrum of the liquid crystal prepared in Example 13 of the present invention and the asymmetry factor of the circularly polarized light generated when light of different wavelengths passes through the liquid crystal are shown.

[0038] Figure 8 The transmission spectrum of the liquid crystal prepared in Example 14 of the present invention and the asymmetry factor of the circularly polarized light generated when light of different wavelengths passes through the liquid crystal are shown. Detailed Implementation

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0040] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0041] Example 1: Preparation of the compound shown in Formula I

[0042] (1) Ethyl 4-hydroxybenzoate (16.6 g, 100 mmol) was added to a suspension of 2-butanone (4.8 g, 1.2 equivalences) in sodium hydroxide (300 mL). Subsequently, NaI (18.0 g, 1.2 equivalences) and 6-chlorohexanol (16.4 g, 1.2 equivalences) were added sequentially to the resulting suspension. The resulting mixture was stirred at 75 °C for 24 h. After cooling to room temperature, the reaction mixture was dried under reduced pressure, and an aqueous solution of NaOH (0.4 mol / L, 300 mL) was added, followed by extraction three times with 100 mL of diethyl ether. The organic phases were combined and dried under reduced pressure at room temperature to obtain the preproduct. The preproduct was then added to an aqueous solution of KOH (0.5 mol / L, 300 mL). The reaction system was refluxed for 5 h. After cooling to room temperature, the resulting mixture was washed three times with 100 mL of diethyl ether. The resulting aqueous phase was acidified with hydrochloric acid and filtered to obtain formula b, which is a white solid (14.8 g, 62% yield).

[0043] (2) The compound b obtained in the previous step (10 g, 41.97 mmol) was added to a solution of N,N-dimethylaniline (4.3 g, 1.1 equivalents) in 1,4-dioxane (100 mL). The reaction mixture was heated to 60 °C and acryloyl chloride (4.2 g, 1.1 equivalents) was slowly added. The reaction mixture was stirred at 60 °C for 3 hours. After cooling to room temperature, the mixture was poured into water (700 mL). The crude product was obtained by filtration. Subsequently, it was purified by silica gel column chromatography (dichloromethane:methanol = 10:1) to give pure compound c as a white solid (8.5 g, 69.0% yield).

[0044] (3) Cholesterol (2.0 g, 5.17 mmol), the compound shown in Formula C (1.8 g, 1.2 equivalents), and 4-dimethylaminopyridine (DMAP, 60 mg, 0.1 equivalents) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (20 mL) and N,N'-dicyclohexylcarboimide (DCC, 1.4 g, 1.3 equivalents) were added. The resulting mixture was stirred at room temperature for 52 hours. After filtration and rotary evaporation, the filtrate was separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula I as a white solid (2.1 g, 62% yield).

[0045] The characterization results of each intermediate product are as follows: b: 1 H NMR (400 MHz, DMSO- d 6) δ 12.60 (s, 1H), 7.88 (d,J = 8.8 Hz, 2H),7.00 (d, J = 8.8 Hz, 2H), 4.36 (s, 1H), 4.03 (t, J = 6.5 Hz, 2H), 3.40 (t, J =5.8 Hz, 2H), 1.73 (p, J = 6.6 Hz, 2H), 1.40 (m, 6H). 13 C NMR (101 MHz, DMSO- d 6)δ 167.5, 162.8, 131.8, 123.2, 114.7, 68.2, 61.1, 32.9, 29.1, 25.8, 25.7. FTMS(APCI) (m / z): calcd. for C 13 H 17 O4237.1132, found: 237.1128 [M-H] - . c: 1 H NMR (300 MHz, CDCl3) δ 8.05 (d, J = 8.9 Hz, 2H), 6.93 (d, J = 8.9Hz, 2H), 6.40 (dd, J = 17.3, 1.5 Hz, 1H), 6.12 (dd, J = 17.3, 10.4 Hz, 1H),5.82 (dd, J = 10.4, 1.5 Hz, 1H), 4.18 (t, J = 6.7 Hz, 2H), 4.03 (t, J = 6.4 Hz,2H), 1.92 – 1.78 (m, 2H), 1.72 (m, 2H), 1.60 – 1.36 (m, 4H). 13 C NMR (101 MHz,Chloroform- d ) δ 171.7, 166.4, 163.6, 132.4, 130.6, 128.6, 121.5, 114.2, 68.1,64.5, 29.0, 28.6, 25.73, 25.71. FTMS (APCI) (m / z): calcd. for C 16 H19 O5291.1238,found: 291.1238 [M-H] - . I: 1 H NMR (400 MHz, CDCl3) δ 7.98 (d, J = 8.8 Hz, 2H), 6.89 (d, J = 8.8Hz, 2H), 6.40 (dd, J = 17.3, 1.3 Hz, 1H), 6.12 (dd, J = 17.3, 10.4 Hz, 1H),5.82 (dd, J = 10.4, 1.3 Hz, 1H), 5.41 (d, J = 4.3 Hz, 1H), 4.87 – 4.78 (m, 1H),4.17 (t, J = 6.6 Hz, 2H), 4.01 (t, J = 6.4 Hz, 2H), 2.45 (d, J = 7.8 Hz, 2H),2.07 – 1.64 (m, 10H), 1.59 – 1.43 (m, 10H), 1.39 – 0.97 (m, 17H), 0.92 (d, J =6.5 Hz, 3H), 0.87 (dd, J = 6.6, 1.6 Hz, 6H), 0.69 (s, 3H). 13 C NMR (101 MHz,CDCl3) δ 162.73, 131.53, 130.56, 128.58, 122.68, 113.96, 67.95, 64.49, 56.72,56.15, 42.34, 39.76, 39.53, 38.31, 37.07, 36.68, 36.20, 35.82, 31.95, 31.90,29.02, 28.56, 28.25, 28.03, 27.96, 25.74, 25.72, 24.31, 23.85, 22.84, 22.58,21.07, 19.40, 18.73, 11.88. FTMS (ESI) (m / z): calcd. for C 43 H 64O5Na 683.4646,found: 683.4632 [M+Na] + . Example 2: Preparation of the compound shown in Formula II

[0046] Diosgenin (2.0 g, 4.82 mmol), the compound shown in Formula C (1.7 g, 1.2 equivalents), and 4-dimethylaminopyridine (DMAP, 59 mg, 0.1 equivalents) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (20 mL) and N,N'-dicyclohexylcarboimide (DCC, 1.3 g, 1.3 equivalents) were added. The resulting mixture was stirred at room temperature for 52 hours. After filtration and rotary evaporation, the filtrate was separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula II as a white solid (2.0 g, 60% yield).

[0047] The characterization results of the product are as follows: II: FTMS (APCI) (m / z): calcd. for C 43 H 61 O7689.4412, found: 689.4460 [M+H] + . Example 3: Preparation of the compound shown in Formula III

[0048] Ergosterol (2.0 g, 5.04 mmol), the compound shown in Formula C (1.8 g, 1.2 equivalents), and 4-dimethylaminopyridine (DMAP, 62 mg, 0.1 equivalents) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (20 mL) and N,N'-dicyclohexylcarboimide (DCC, 1.4 g, 1.3 equivalents) were added. The resulting mixture was stirred at room temperature for 52 hours. After filtration and rotary evaporation, the filtrate was separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula III as a white solid (1.9 g, 55% yield).

[0049] The characterization results of the product are as follows: III: FTMS (APCI) (m / z): calcd. for C 44 H 63 O5671.4671, found: 671.4666 [M+H] + . Example 4: Preparation of the compound shown in Formula IV

[0050] Stigmasterol (2.0 g, 4.84 mmol), the compound shown in Formula C (1.7 g, 1.2 equivalents), and 4-dimethylaminopyridine (DMAP, 59 mg, 0.1 equivalents) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (20 mL) and N,N'-dicyclohexylcarboimide (DCC, 1.3 g, 1.3 equivalents) were added. The resulting mixture was stirred at room temperature for 52 hours. After filtration and rotary evaporation, the filtrate was separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula IV as a white solid (1.9 g, 57% yield).

[0051] The characterization results of the product are as follows: IV: FTMS (APCI) (m / z): calcd. for C 53 H 73 O8687.4984, found: 687.4983 [M+H] + . Example 5: Preparation of the compound shown in formula V

[0052] 7-Dehydrocholesterol (2.0 g, 5.2 mmol), the compound shown in Formula C (1.8 g, 1.2 equivalents), and 4-dimethylaminopyridine (DMAP, 64 mg, 0.1 equivalents) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (20 mL) and N,N'-dicyclohexylcarboimide (DCC, 1.4 g, 1.3 equivalents) were added. The resulting mixture was stirred at room temperature for 52 hours. After filtration and rotary evaporation, the filtrate was separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula V as a white solid (1.8 g, 52% yield).

[0053] The characterization results of the product are as follows: V:FTMS (APCI) (m / z): calcd. for C 43 H 63 O5659.4671, found: 659.4685 [M+H] + . Example 6: Preparation of the compound shown in Formula VIII

[0054] Cholesterol (5 g, 12.93 mmol) was added to a solution of N,N-dimethylaniline (1.7 g, 1.1 equivalents) in dichloromethane (30 mL). Acryloyl chloride (1.3 g, 1.1 equivalents) was slowly added under ice-water bath conditions. The reaction mixture was stirred at room temperature for 3 hours and then concentrated, followed by dissolution in water (700 mL). The crude product was obtained by filtration. It was then slurried with ethanol to give a pure white solid of formula VIII (4.9 g, 86% yield).

[0055] The characterization results of the product are as follows: VIII: 1 H NMR (400 MHz, CDCl3) δ 6.39 (dd, J = 17.3, 1.4 Hz, 1H), 6.10(dd, J = 17.3, 10.4 Hz, 1H), 5.80 (dd, J = 10.4, 1.4 Hz, 1H), 5.39 (d, J = 4.8Hz, 1H), 4.74 – 4.64 (m, 1H), 2.36 (d, J = 7.9 Hz, 2H), 2.06 – 1.78 (m, 5H), 1.69 – 1.42 (m, 8H), 1.40 – 0.98 (m, 16H), 0.92 (d, J = 6.5 Hz, 3H), 0.87 (dd, J = 6.6, 1.7 Hz, 6H), 0.68 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 130.28, 129.06,122.74, 56.70, 56.14, 50.04, 39.74, 39.53, 38.11, 37.00, 36.62, 36.20, 35.81,31.93, 31.88, 28.24, 28.03, 27.78, 24.30, 23.84, 22.83, 22.58, 21.05, 19.34,18.73, 11.87. FTMS (ESI) (m / z): calcd. for C 30 H 48 O2Na 463.3547, found: 463.3546[M+Na] + . Example 7: Preparation of the compound shown in Formula IX

[0056] Diosgenin (5 g, 12.06 mmol) was added to a solution of N,N-dimethylaniline (1.6 g, 1.1 equivalents) in dichloromethane (30 mL). Acryloyl chloride (1.2 g, 1.1 equivalents) was slowly added under ice-water bath conditions. The reaction mixture was stirred at room temperature for 3 hours and then concentrated, followed by dissolution in water (700 mL). The crude product was obtained by filtration. It was then slurried with ethanol to give a pure white solid of formula IX (4.8 g, 85% yield).

[0057] The characterization results of the product are as follows: IX: FTMS (ESI) (m / z): calcd. for C 30 H 45 O4469.3313, found: 469.3320 [M+H] + . Example 8: Preparation of the compound shown in formula X

[0058] Ergosterol (5 g, 12.61 mmol) was added to a solution of N,N-dimethylaniline (1.7 g, 1.1 equivalents) in dichloromethane (30 mL). Acryloyl chloride (1.3 g, 1.1 equivalents) was slowly added under ice-water bath conditions. The reaction mixture was stirred at room temperature for 3 hours and then concentrated, followed by dissolution in water (700 mL). The crude product was obtained by filtration. It was then slurried with ethanol to give a pure white solid of formula X (4.7 g, 82% yield).

[0059] The characterization results of the product are as follows: X: FTMS (ESI) (m / z): calcd. for C 31 H 47 O2451.3571, found: 451.3569 [M+H] + . Example 9: Preparation of the compound shown in Formula XIV

[0060] (1) 0.5 g (4.54 mmol) of p-diphenol, 2.9 g (2.2 equivalences) of the compound shown in Formula G, and 4-dimethylaminopyridine (DMAP, 55 mg, 0.1 equivalences) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (30 mL) and N,N'-dicyclohexylcarboimide (DCC, 2.2 g, 2.4 equivalences) were added. The resulting mixture was stirred at room temperature for 52 hours. After the reaction was complete, the mixture was filtered, and the filtrate was evaporated to dryness and separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in Formula XIV as a white solid (2.6 g, 87% yield).

[0061] The characterization results of each intermediate product are as follows: XIV: 1 H NMR (500 MHz, CDCl3) δ 8.14 (d, J = 8.9 Hz, 4H), 7.26 (s, 4H), 6.97 (d, J = 8.9 Hz, 4H), 6.40 (dd, J = 17.3, 1.4 Hz, 2H), 6.13 (dd, J = 17.3,10.4 Hz, 2H), 5.82 (dd, J = 10.4, 1.3 Hz, 2H), 4.19 (t, J = 6.6 Hz, 4H), 4.06(t, J = 6.4 Hz, 4H), 1.88 – 1.81 (m, 4H), 1.73 (dt, J = 14.1, 6.8 Hz, 4H), 1.55(dt, J = 14.7, 6.9 Hz, 4H), 1.48 (q, J = 8.7, 8.2 Hz, 4H). 13 C NMR (126 MHz, CDCl3) δ 166.3, 164.8, 163.5, 148.5, 132.3, 130.4, 128.6, 122.6, 121.6, 114.3, 68.1, 64.4, 29.0, 28.6, 25.7. FTMS (APCI) (m / z):calcd. forC 38 H 42 O 10 Na681.2670, found: 681.2675 [M+Na] + . Example 10: Preparation of the compound shown in formula XVI

[0062] (1) Ethyl 4-hydroxybenzoate (16.6 g, 100 mmol) was added to a 2-butanone suspension (300 mL) containing sodium hydroxide (4.8 g, 1.2 equivalence). Subsequently, NaI (18.0 g, 1.2 equivalence) and 4-chloro-1-butanol (13.03 g, 1.2 equivalence) were added sequentially to the resulting suspension. The resulting mixture was stirred at 75 °C for 24 hours. After cooling to room temperature, the reaction mixture was dried under reduced pressure, and an aqueous solution of NaOH (0.4 mol / L, 300 mL) was added, followed by extraction three times with 100 mL of diethyl ether. The organic phases were combined and dried under reduced pressure at room temperature to obtain the preproduct. The preproduct was then added to an aqueous solution of KOH (0.5 mol / L, 300 mL). The reaction system was refluxed for 5 hours. After cooling to room temperature, the resulting mixture was washed three times with 100 mL of diethyl ether. The resulting aqueous phase was acidified with hydrochloric acid and filtered to obtain a white solid of formula F-3 (12.6 g, 60% yield).

[0063] (2) The compound of formula F-3 obtained in the previous step (10 g, 47.57 mmol) was added to a solution of N,N-dimethylaniline (6.34 g, 1.1 equivalents) in 1,4-dioxane (100 mL). The reaction mixture was heated to 60 °C and acryloyl chloride (4.74 g, 1.1 equivalents) was slowly added. The reaction mixture was stirred at 60 °C for 3 hours. After cooling to room temperature, the mixture was poured into water (700 mL). The crude product was obtained by filtration. Subsequently, it was purified by silica gel column chromatography (dichloromethane:methanol = 10:1) to give pure formula G-3 as a white solid (9.0 g, 65% yield).

[0064] (3) 0.5 g (4.54 mmol) of p-diphenol, 2.64 g (2.2 equivalences) of the compound shown in formula G-3, and 4-dimethylaminopyridine (DMAP, 55 mg, 0.1 equivalences) were added to a 200 mL reaction tube. After purging with nitrogen three times, dichloromethane (30 mL) and N,N'-dicyclohexylcarboimide (DCC, 2.2 g, 2.4 equivalences) were added. The resulting mixture was stirred at room temperature for 52 hours. After the reaction was complete, the mixture was filtered, and the filtrate was evaporated to dryness and separated by silica gel column chromatography (eluent: dichloromethane) to obtain the compound shown in formula XVI as a white solid (2.4 g, 88% yield).

[0065] The characterization results of each intermediate product are as follows: F-3: FTMS (APCI) (m / z): calcd. for C 11 H 13O4209.0819, found: 209.0822 [MH] - . G-3: FTMS (APCI) (m / z): calcd. for C 14 H 15 O5263.0925, found: 263.0924 [MH] - . XVI: FTMS (APCI) (m / z): calcd. for C 34 H 35 O 10 603.2225, found: 603.2228 [M+H] + . Example 11: Based on the compound shown in Formula I and the compound shown in Formula XIV, 120 o C. Preparation of cholesteric phase-fixed liquid crystals The compound shown in Formula I (10 mg), the compound shown in Formula XIV (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was then heated to 100 °C. o C was melted. The molten system was then encapsulated between two 1.5 × 1.5 cm quartz plates at 120°C. o Curing at C for 2 hours yielded a cholesteric phase-fixed liquid crystal.

[0066] Example 12: Based on the compound shown in Formula I and the compound shown in Formula XIV, 130 o C. Preparation of cholesteric phase-fixed liquid crystals The compound shown in Formula I (10 mg), the compound shown in Formula XIV (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was then heated to 100 °C. o C was melted. The molten system was then encapsulated between two 1.5 × 1.5 cm quartz plates at 130°C. o Curing at C for 2 hours yielded a cholesteric phase-fixed liquid crystal.

[0067] Example 13: Preparation of cholesteric phase-immobilized liquid crystals at 140 °C based on compounds of Formula I and Formula XIV. The compound shown in Formula I (10 mg), the compound shown in Formula XIV (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was then heated to 100 °C. o C was melted. The molten system was then encapsulated between two 1.5 × 1.5 cm quartz plates at 140°C. o Curing at C for 2 hours yielded a cholesteric phase-fixed liquid crystal.

[0068] Example 14: Based on the compound shown in Formula I and the compound shown in Formula XIV, 150 o C. Preparation of cholesteric phase-fixed liquid crystals The compound shown in Formula I (10 mg), the compound shown in Formula XIV (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was heated to 100 °C to melt. Subsequently, the molten system was encapsulated between two 1.5 × 1.5 cm quartz plates and cured at 150 °C for 2 hours to obtain a cholesteric-phase-fixed liquid crystal.

[0069] Example 15: Based on the compound shown in Formula III and the compound shown in Formula XVIII, 130 o C. Preparation of cholesteric phase-fixed liquid crystals The compound shown in Formula III (10 mg), the compound shown in Formula XVIII (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was heated to 100 °C to melt. Subsequently, the molten system was encapsulated between two 1.5 × 1.5 cm quartz plates and cured at 130 °C for 2 hours to obtain a cholesteric-phase-fixed liquid crystal.

[0070] Example 16: Based on the compound shown in Formula XI and the compound shown in Formula XVIII, 130 o C. Preparation of cholesteric phase-fixed liquid crystals The compound shown in Formula XI (10 mg), the compound shown in Formula XVIII (10 mg), and dichloromethane (2 mL) were added to a 4 mL sample vial. After sonication for 5 minutes, the mixture was dried on a hot plate at 60 °C to obtain a white, waxy solid. The solid was heated to 100 °C to melt it. Subsequently, the molten system was encapsulated between two 1.5 × 1.5 cm quartz plates and cured at 130 °C for 2 hours to obtain a cholesteric-phase-fixed liquid crystal.

[0071] Example 17: Evaluation of circular polarization conversion performance using the wide-reflectivity liquid crystals prepared in Examples 11-16 as an example. Unpolarized light was passed through the fabricated wide-reflectivity liquid crystal, and the circular polarization conversion performance of the material was evaluated using a CPL-300 instrument. The circular dichroism absorption performance of the material was evaluated using a JASCO J810 instrument. The absorption and transmission performance of the material were evaluated using a Lambda 950 instrument.

[0072] Table 1. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 11 to convert light of different wavelengths.

[0073] Table 2. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 12 to convert light of different wavelengths.

[0074] Table 3. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 13 to convert light of different wavelengths.

[0075] Table 4. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 14 to convert light of different wavelengths.

[0076] Table 5. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 15 to convert light of different wavelengths.

[0077] Table 6. Data on the ability of the wide-reflectivity liquid crystal prepared in Example 16 to convert light of different wavelengths.

[0078] From Table 1-6, Figure 5-8 The data shows that the novel cholesteric phase curing method of this invention can avoid the addition of initiators, avoid the use of ultraviolet light, and can achieve a change in the photonic bandgap from red to cyan without altering the internal composition of the material. Furthermore, these materials can all convert unpolarized light into circularly polarized light with high polarization purity.

[0079] The above embodiments of the present invention are merely illustrative examples to clearly illustrate the invention and are not intended to limit the implementation of the invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description; therefore, it is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention should be within the scope of protection of the present invention.

Claims

1. A polymerizable chiral liquid crystal monomer compound, the structural formula of which is shown in Formula 1 or Formula 2: ； in, R represents one or more achiral aromatic rings, achiral fused aromatic rings, or achiral unbranched alkyl chains of different lengths, specifically selected from any one of the following groups: benzene, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, naphthidine, phenanthridine, imidazole, quinoline, isoquinoline, 1,3,5-triazine, pyrimidine, benzophenone, cyanobenzene, triarylborone, diphenyl sulfone, methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, or derivatives of any substitution of the above groups; R * It is selected from any one of the following chiral groups: cholesterol, diosgenin, ergosterol, stigmasterol, rosin acid, dehydrorosin acid, ambroxol, cedrol, menthol, citronellol, α-terpineol, mandelic acid, tartaric acid, chiral α-amino acid, chiral β-amino acid, chiral alkyl chain, chiral polypeptide group, or derivatives of the above groups with arbitrary substitution.

2. The method for preparing the chiral liquid crystal monomer compound according to claim 1, comprising the following steps S1-S3 or S4: S1, the compound shown in formula A1 and the compound shown in formula A2 undergo an etherification reaction, followed by a saponification reaction to obtain the compound shown in formula B; ； The definition of R in formula B is the same as that in formula 1 of claim 1; S2. The compound shown in formula B undergoes an esterification reaction with acryloyl chloride to obtain the compound shown in formula C. ； S3. The compound shown in formula C and the compound shown in formula D undergo an esterification reaction to obtain the compound shown in formula 1 in claim 1. ； In formula C, R * The definition is the same as that in formula 1 or formula 2 of claim 1; S4, the compound shown in formula D, is subjected to an esterification reaction with acryloyl chloride to obtain the compound shown in formula 2 in claim 1.

3. The preparation method according to claim 2, characterized in that: In step S1, the etherification reaction is carried out in the presence of sodium hydroxide and sodium iodide. The reaction solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 2-butanone, acetonitrile, 1,4-dioxane, and tetrahydrofuran. The reaction temperature is 30-100°C and the reaction time is 24-48 hours. In step S2, the esterification reaction is carried out in the presence of N,N-dimethylaniline, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-24 hours. In step S3, the esterification reaction is carried out in the presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-100 hours. In step S4, the esterification reaction is carried out in the presence of N,N-dimethylaniline, the reaction solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, the reaction temperature is 0-90℃, and the reaction time is 3-24 hours.

4. A non-chiral liquid crystal monomer compound, the structural formula of which is shown in Formula 3: ； In the formula, R represents one or more achiral aromatic rings, achiral fused aromatic rings, or achiral unbranched alkyl chains of different lengths, selected from any of the following groups: benzene, biphenyl, terphenyl, naphthalene, phenanthrene, pyridine, naphthidine, phenanthridine, imidazole, quinoline, isoquinoline, 1,3,5-triazine, pyrimidine, benzophenone, cyanobenzene, triarylborone, diphenyl sulfone, methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, or derivatives of any substitution of the above groups.

5. A method for preparing the non-chiral liquid crystal monomer compound according to claim 4, comprising the following steps: The compound shown in Formula C is esterified with p-diphenol to obtain the non-chiral liquid crystal monomer compound of claim 4; ； The esterification reaction was carried out in the presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine.

6. A method for curing cholesteric liquid crystal, comprising the following steps: The polymerizable chiral liquid crystal monomer compound of claim 1 is mixed with the non-chiral liquid crystal monomer compound of claim 4 to obtain a co-assembled system; The co-assembled system is heated to a molten state, then encapsulated in a container, and thermosetting at a temperature of 100-180°C to obtain a cured cholesteric liquid crystal material.

7. The curing method according to claim 6, characterized in that: The mass ratio of the polymerizable chiral liquid crystal monomer compound to the non-chiral liquid crystal monomer compound is 50:30-70, preferably 50:50; And / or, the temperature of the thermosetting treatment is 120-150°C and the time is 30-360 minutes, preferably 120 minutes.

8. A method for recoloring the reflective color of a cholesteric liquid crystal, comprising the following steps: The polymerizable chiral liquid crystal monomer compound of claim 1 is mixed with the non-chiral liquid crystal monomer compound of claim 4 to obtain a co-assembled system; The co-assembled system is heated to a molten state and then encapsulated in a container. By performing thermosetting treatment at different thermosetting temperatures, cured cholesteric liquid crystal materials with different reflective colors are obtained; the thermosetting temperature range is 100-180℃.

9. The method according to claim 7 or 8, characterized in that: The preparation of the co-assembled system includes the following steps: The polymerizable chiral liquid crystal monomer compound and the non-chiral liquid crystal monomer compound are dissolved in an organic solvent, ultrasonically treated, and then dried on a hot stage at 25-180°C to obtain the co-assembled system. Preferably, the organic solvent is selected from at least one of 1,4-dioxane, tetrahydrofuran, dichloromethane, and trichloromethane, and the ultrasonic treatment time is 1-60 minutes.

10. A cured cholesteric liquid crystal material, prepared by means of the polymerizable chiral liquid crystal monomer compound of claim 1 and the non-chiral liquid crystal monomer compound of claim 4, using the method of claim 8 or 9; The cholesteric liquid crystal material has circular polarization conversion properties, and the absolute value of its luminescence asymmetry factor is not less than 1.5.

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