Fluorine-containing ferroelectric nematic liquid crystal molecules and use thereof

Abstract

The application relates to a fluorine-containing ferroelectric nematic liquid crystal molecule and application thereof, relates to the technical field of photoelectric materials, and solves the problem of low dielectric constant of traditional liquid crystal materials which restricts the application of the liquid crystal materials in photoelectric functional devices. The molecule adopts a unique non-chiral V-shaped configuration design, takes a benzene ring as a core skeleton, and realizes performance optimization through meta-connection of differentiated functional side chains. In the molecular structure design, a strong electron-withdrawing trifluoromethyl substituent is introduced into the benzene ring 2, 4 of one end of the side chain, the intermolecular interaction force is enhanced, and the long-range order of the material is maintained; the other end adopts an alkoxy flexible chain structure, which not only improves the solubility of the material, but also enhances the thermal stability. The raw material is easy to obtain, the preparation is simple, the fluorine-containing ferroelectric liquid crystal molecule is in a nematic phase, the dielectric constant can be as high as 1.4 x 10 4 (1 kHz), and has a wide ferroelectric nematic phase transition temperature, high polarization intensity and nonlinear optical response, and has important application value in the field of photoelectric functional materials.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic materials technology, specifically to a fluorine-containing ferroelectric nematic liquid crystal molecule and its applications. Background Technology

[0002] Liquid crystal materials are a special class of mesocrystalline substances that combine the fluidity of liquids with the anisotropy of crystals. While these materials lose their solid-state rigidity in the molten state, their molecules retain their ordered orientation, thus exhibiting unique physical properties on a macroscopic scale. Based on the characteristic that liquid crystal molecules can change orientation under the influence of an external field, the light field can be modulated by controlling the molecular arrangement, and these materials have been widely used in display devices and other fields. However, as non-polar fluids, the low dielectric constant of traditional liquid crystal materials severely limits their application in optoelectronic functional devices. This technological bottleneck has been fundamentally resolved with the discovery of ferroelectric liquid crystal materials.

[0003] Ferroelectric liquid crystal materials are a class of functional liquid crystal materials exhibiting spontaneous polarization properties. Their molecular structure features a separation of positive and negative charge centers, forming an inherent dipole moment. Below the Curie temperature, they can spontaneously polarize, and the polarization direction can reversibly change with an external electric field. Compared to traditional liquid crystal materials, ferroelectric liquid crystals possess significant advantages such as fast response speeds (down to the microsecond level) and high dielectric constants, making them highly promising for applications in cutting-edge fields such as optoelectronic modulators and non-volatile memories.

[0004] However, current research reports on ferroelectric liquid crystal materials are still relatively limited, and the development of novel high-performance ferroelectric liquid crystal materials has become an important research direction in the field of optoelectronic functional materials. Summary of the Invention

[0005] To address the problem that the low dielectric constant of traditional liquid crystal materials restricts their application in optoelectronic functional devices, this invention proposes a fluorine-containing ferroelectric nematic liquid crystal molecule and its application.

[0006] The specific technical solution of the present invention is as follows:

[0007] A fluorine-containing ferroelectric nematic liquid crystal molecule has the following structure:

[0008] It was named ETC-912.

[0009] Furthermore, the present invention also provides an application of the above-mentioned fluorine-containing ferroelectric nematic liquid crystal molecules in the field of optoelectronic materials.

[0010] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0011] This invention provides a fluorine-containing ferroelectric nematic liquid crystal material with an innovative molecular structure design, which shows excellent application potential in the field of optoelectronic functional devices. The liquid crystal molecule adopts a unique achiral "V"-shaped configuration design, with a benzene ring as the core framework, and performance optimization achieved through meta-linked differentiated functional side chains. In the molecular structure design, strong electron-withdrawing trifluoromethyl substituents are introduced at the 2 and 4 positions of the benzene ring on one end of the side chain, significantly enhancing intermolecular interactions and effectively maintaining the long-range order of the material; the other end adopts an alkoxy flexible chain structure, which not only improves the material's solubility but also enhances its thermal stability.

[0012] Experimental results show that the fluorine-containing ferroelectric liquid crystal material provided by this invention exhibits excellent comprehensive performance: under 1kHz testing conditions, its dielectric constant reaches as high as 1.4 × 10⁻⁶. 4 It exhibits wide-temperature-range ferroelectric nematic phase characteristics, high polarization intensity, and significant nonlinear optical response properties. These outstanding performance indicators make it valuable for applications in multiple high-tech fields, including but not limited to high-speed optical communication devices, next-generation liquid crystal display units, and high-efficiency nonlinear optical elements. Of particular note is that the material's high dielectric constant and fast response characteristics provide a new material option for developing high-performance electro-optic modulation devices, while its excellent nonlinear optical properties open up new avenues for the research and development of nonlinear optical devices such as optical switches and optical limiters. Attached Figure Description

[0013] Figure 1 A route diagram for the preparation of fluorine-containing ferroelectric nematic liquid crystal molecules provided by the present invention;

[0014] Figure 2 For the intermediate 1 described in the embodiment 1 H-NMR spectrum;

[0015] Figure 3 For the intermediate 1 described in the embodiment 13 C-NMR spectrum;

[0016] Figure 4 For the intermediate 2 described in the embodiment 1 H-NMR spectrum;

[0017] Figure 5 For the intermediate 2 described in the embodiment 13 C-NMR spectrum;

[0018] Figure 6 For the intermediate 3 described in the embodiment 1 H-NMR spectrum;

[0019] Figure 7 For the intermediate 3 described in the embodiment 13C-NMR spectrum;

[0020] Figure 8 For the intermediate 4 described in the embodiment 1 H-NMR spectrum;

[0021] Figure 9 For the intermediate 4 described in the embodiment 13 C-NMR spectrum;

[0022] Figure 10 For the intermediate 5 described in the embodiment 1 H-NMR spectrum;

[0023] Figure 11 For the intermediate 5 described in the embodiment 13 C-NMR spectrum;

[0024] Figure 12 For the intermediate 6 described in the embodiment 1 H-NMR spectrum;

[0025] Figure 13 For the intermediate 6 described in the embodiment 13 C-NMR spectrum;

[0026] Figure 14 For the intermediate 7 described in the embodiment 1 H-NMR spectrum;

[0027] Figure 15 For the intermediate 7 described in the embodiment 13 C-NMR spectrum;

[0028] Figure 16 The fluorine-containing ferroelectric nematic liquid crystal molecules in the examples 1 H-NMR spectrum;

[0029] Figure 17 The fluorine-containing ferroelectric nematic liquid crystal molecules in the examples 13 C-NMR spectrum;

[0030] Figure 18 DSC image of fluorine-containing ferroelectric nematic liquid crystal molecules prepared for the example;

[0031] Figure 19 The hysteresis loop of the fluorine-containing ferroelectric nematic liquid crystal molecules prepared for the example at 100°C;

[0032] Figure 20 The SHG signal intensity of the fluorine-containing ferroelectric nematic liquid crystal molecules prepared in the examples is shown in different temperature regions.

[0033] Figure 21Dielectric property test diagram of fluorine-containing ferroelectric nematic liquid crystal molecules prepared for the example;

[0034] Figure 22 Thermogravimetric analysis diagram of the novel fluorine-containing ferroelectric nematic liquid crystal molecules prepared for the example. Detailed Implementation

[0035] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0036] Example.

[0037] The synthetic routes for intermediates 1, 2, 3, 4, 5, 6, 7, and the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 are shown in the attached instructions. Figure 1 As shown.

[0038] Among them, 3,5-difluorobenzonitrile (raw material 1, CAS: 64248-63-1), 3-bromophenylboronic acid (raw material 4, CAS: 89598-96-9), 3,5-bis(trifluoromethylbenzoic acid) (raw material 5, CAS: 725-89-3), 4-bromo-2,6-difluorophenol (raw material 6, CAS: 104197-13-9), and pinacol diboronate (raw material 7, CAS: 73183-34-3) were all directly purchased from Shanghai Haohong Biomedical Technology Co., Ltd. p-Benzoquinone (raw material 2, CAS: 106-51-4) and bromobutane (raw material 3, CAS: 109-65-9) were directly purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0039] I. Synthesis of Intermediate 1:

[0040] 3,5-Difluorobenzonitrile (10 g, 35.94 mmol, 1 equivalent) and anhydrous tetrahydrofuran (300 mL) were added to a three-necked flask. The system was maintained below 0°C. Lithium magnesium chloride (2,2,6,6-tetramethylpiperidine) salt (11.33 g, 46.73 mmol, 1.3 equivalent) was added dropwise, and the system was allowed to return to room temperature. Then, iodine (10 g, 39.54 mmol, 1.1 equivalent) was added. The reaction was allowed to proceed for 8 hours at room temperature. After the reaction was complete, the reaction was quenched with saturated ammonium chloride, extracted with ethyl acetate, and anhydrous sodium sulfate was added to the organic phase for drying. The mixture was filtered, and the solvent was evaporated under reduced pressure. The crude product was purified by column chromatography using n-hexane:ethyl acetate = 10:1 as the eluent, yielding a white solid, which was intermediate 1, with a yield of 81%. The structural formula is as follows:

[0041] .

[0042] NMR characterization results:

[0043] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 7.76 (m, 2H);

[0044] Carbon spectrum: 13 C NMR (125 MHz, DMSO) δ 157.25, 157.18, 155.23, 155.17, 118.15,118.12, 117.99, 117.96, 115.94, 115.91, 115.87, 108.17, 108.11, 108.04,94.23, 94.07, 93.91;

[0045] Mass spectrometry characterization results: ESI (m / z): [M+H] ＋ Calcd. for C7H2F2IN,264.92; found, 265.88.

[0046] II. Synthesis of Intermediate 2:

[0047] Intermediate 1 (7.5 g) was dissolved in dichloromethane (180 mL) in a three-necked flask. The reaction system was maintained at -10 °C under ice bath conditions. Under nitrogen protection, diisobutylaluminum hydride (30 mL, 1 M in THF) was slowly added dropwise to the system. After the system was brought back to room temperature and reacted for 1 hour, the reaction was quenched with 6 M hydrochloric acid (150 mL). Extraction was performed with dichloromethane, and anhydrous sodium sulfate was added to the organic phase for drying. The mixture was filtered, and the solvent was evaporated under reduced pressure. The crude product was purified by column chromatography using petroleum ether:dichloromethane = 5:1 as the eluent to obtain a pale yellow solid, which was intermediate 2, with a yield of 68%. The structural formula is as follows:

[0048] .

[0049] NMR characterization results:

[0050] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 9.84 (s, 1H), 7.64 (m, 2H);

[0051] Carbon spectrum: 13C NMR (125 MHz, DMSO) δ 191.66, 163.85, 163.85, 138.14, 109.43,109.43, 67.89;

[0052] Mass spectrometry characterization results: ESI (m / z): [M+H] ＋ Calcd. for C7H3F2IO, 267.92; found, 268.89.

[0053] III. Synthesis of Intermediate 3:

[0054] In a three-necked flask, intermediate 3 (5 g, 18.66 mmol, 1 equivalent), copper acetate monohydrate (268 mg, 1.34 mmol, 0.072 equivalent), and TBHP (6.73 g, 74.63 mmol, 0.072 equivalent) were added to dimethyl sulfoxide (60 mL), followed by p-benzoquinone (3 g, 27.98 mmol, 1.5 equivalent). The reaction was carried out overnight at 120 °C. After the reaction was complete, the mixture was cooled to room temperature and extracted with water / ethyl acetate. Anhydrous sodium sulfate was added to the organic phase for drying, and the mixture was filtered. The solvent was evaporated under reduced pressure, and the crude product was purified by column chromatography using ethyl acetate:petroleum ether = 1:10 as the eluent. The resulting yellow solid was intermediate 3, with a yield of 73%. The structural formula is as follows:

[0055] .

[0056] NMR characterization results:

[0057] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 9.56 (s, 1H), 7.97 (m, 2H), 7.17 (m, 2H), 6.78 (m, 2H);

[0058] Carbon spectrum: 13 C NMR (125 MHz, DMSO) δ 166.65, 166.63, 166.61, 157.25, 157.18,155.23, 155.17, 154.63, 144.56, 124.31, 124.25, 124.18, 122.66, 116.43,115.53, 115.51, 115.37, 115.35, 94.23, 94.07, 93.91;

[0059] Mass spectrometry characterization results:

[0060] ESI (m / z): [M+H]＋ Calculated for C 13 H7F2IO3, 375.94; found, 376.92.

[0061] IV. Synthesis of Intermediate 4:

[0062] In a three-necked flask, bromobutane (1.82 g, 13.29 mmol, 1 equivalent), potassium carbonate (3.67 g, 26.59 mmol, 2 equivalents), and intermediate 3 (5 g, 13.29 mmol, 1 equivalent) were added to N,N-dimethylformamide (30 mL), and the reaction was carried out overnight at 100 °C. After the reaction was completed, the mixture was extracted with ethyl acetate and washed three times with water. Anhydrous sodium sulfate was added to the organic phase for drying, filtered, and the solvent was evaporated under reduced pressure to obtain a crude product. Methanol was added to the crude product, and the mixture was stirred at low temperature for 1 hour under an ethanol dry ice bath. The mixture was then filtered, washed with a small amount of petroleum ether, and the filter cake was a pale yellow solid, which was intermediate 4, with a yield of 62%. The structural formula is as follows:

[0063] .

[0064] NMR characterization results:

[0065] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 7.30(m, 2H), 7.18 (m, 2H), 6.99 (m,2H), 3.97 (s, 2H), 1.74 (s, 2H), 1.48 (s, 2H), 1.02 (s, 3H);

[0066] Carbon NMR: 13C NMR (125 MHz, DMSO) δ 166.65, 166.63, 166.61, 157.25, 157.18, 156.53, 155.23, 155.17, 144.56, 124.31, 124.25, 124.18, 122.49, 117.22, 115.53, 115.51, 115.37, 115.35, 94.23, 94.07, 93.91, 67.81, 31.13, 19.20, 13.78;

[0067] Mass spectrometry characterization results: ESI (m / z): [M+H] ＋ Calculated for C 17 H 15 F2IO3,432.00; found,432.99.

[0068] V. Synthesis of Intermediate 5:

[0069] In a three-necked flask, intermediate 4 (3.5 g, 8.1 mmol, 1 equivalent), 3-bromophenylboronic acid (1.95 g, 9.72 mmol, 1.2 equivalent), and 2M sodium carbonate aqueous solution (4 equivalent) were dissolved in dioxane (50 mL). Under nitrogen protection, tetrakis(triphenylphosphine)palladium (190 mg, 0.02 equivalent) was added to the system. The mixture was heated to reflux and reacted overnight. After the reaction was completed and cooled to room temperature, the mixture was filtered through a diatomaceous earth liner. The filter cake was washed with ethyl acetate, and the filtrate was washed three times with water. Anhydrous sodium sulfate was added to the organic phase for drying, followed by filtration and solvent evaporation under reduced pressure. The crude product was then added to a petroleum ether:ethyl acetate ratio of 1:1. The mixture was stirred at low temperature overnight under ethanol dry ice bath conditions, followed by filtration. The filter cake was washed with a small amount of petroleum ether, and the resulting white solid was intermediate 5, with a yield of 59%. The structural formula is as follows:

[0070] .

[0071] NMR characterization results:

[0072] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 7.62 (dd, 4H), 7.51 (s, 1H), 7.42 (s,1H), 7.18 (m, 2H), 6.94 (m, 2H), 4.00 (s, 2H), 1.78 (s, 2H), 1.52 (s, 2H),1.03 (s, 3H);

[0073] Carbon spectrum: 13 C NMR (125 MHz, DMSO) δ 166.05, 166.03, 166.00, 159.95, 159.89,157.94, 157.87, 156.53, 144.88, 133.46, 133.40, 133.34, 132.82, 130.89,130.87, 130.84, 130.03, 127.03, 126.97, 126.91, 126.63, 126.61, 126.59,123.17, 122.64, 117.52, 117.36, 117.20, 116.86, 113.90, 113.88, 113.74, 113.72, 67.81, 31.13, 19.20, 13.78;

[0074] Mass spectrometry characterization results:

[0075] ESI (m / z): [M+H]＋ Calculated for C 23 H 19 BrF2O3, 460.05; found, 461.02.

[0076] VI. Synthesis of Intermediate 6:

[0077] In a three-necked flask, 5 g of bromo-2,6-difluorophenol (23.92 mmol, 1 equivalent), 7.41 g of bis(trifluoromethyl)benzoic acid (7.41 g, 28.71 mmol, 1.2 equivalent), and 8 g of N,N'-dicyclohexylcarbodiimide (DCC, 8.89 g, 43.06 mmol, 0.08 equivalent) were added to 50 mL of anhydrous dichloromethane. The mixture was placed in an ice bath under nitrogen protection. Then, 0.24 g of 4-dimethylaminopyridine (DMAP, 1.91 mmol, 0.08 equivalent) dissolved in 10 mL of dichloromethane was added. The mixture was reacted in an ice bath for 4 hours, then allowed to return to room temperature and reacted overnight. After the reaction was complete, the system was transferred to a saturated aqueous sodium chloride solution and extracted with dichloromethane. Anhydrous sodium sulfate was added to the organic phase for drying, followed by filtration and evaporation of the solvent under reduced pressure. The crude product was purified by column chromatography using petroleum ether:dichloromethane = 1:5 as the eluent, yielding a white solid, which was intermediate 6, in 76.6% yield. The structural formula is as follows:

[0078] .

[0079] NMR characterization results:

[0080] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 8.42 (m, 2H), 8.17 (s, 1H), 7.23 (m, 2H).

[0081] Carbon spectrum: 13C NMR (125 MHz, DMSO) δ 164.73, 164.70, 164.66, 154.54, 154.47,152.52, 152.45, 132.98, 132.97, 132.95, 132.72, 132.71, 132.69, 132.47,132.45, 132.42, 132.21, 130.75, 130.72, 130.69, 130.65, 130.53, 130.37,130.34, 130.32, 130.31, 130.28, 130.21, 125.92, 123.78, 123.70, 123.67, 123.63, 123.60, 123.57, 121.64, 119.50, 118.25, 118.23, 118.16, 118.09, 118.07, 118.03.

[0082] Mass spectrometry characterization results: ESI (m / z): [M+H] ＋ Calculated for C 15 H5BrF8O2,447.93; found,448.91.

[0083] VII. Synthesis of Intermediate 7:

[0084] Intermediate 6 (7 g, 15.59 mmol, 1 equivalent) was dissolved in ultra-dry tetrahydrofuran (50 mL) in a three-necked flask. The solution was cooled to -78 °C, and 2 M n-butyllithium solution (5 mL) was added dropwise over 5 minutes. After stirring for 0.5 hours, pinacol diboronate (4.75 g, 18.7 mmol, 1.2 equivalent) was added to the system. The mixture was allowed to return to room temperature and reacted overnight. After the reaction was complete, 2 M HCl was added to the system to adjust the pH to 3-4. Extraction was performed with diethyl ether, and anhydrous sodium sulfate was added to the organic phase for drying. The mixture was filtered, and the solvent was evaporated under reduced pressure. A yellow solid, intermediate 7, was obtained, with a yield of 61.2%. The structural formula is as follows:

[0085] .

[0086] NMR characterization results:

[0087] Hydrogen spectrum: 1 H NMR (500 MHz, DMSO) δ 8.42 (s, 3H), 6.77 (m, 2H), 1.28 (s, 12H);

[0088] Carbon spectrum: 13C NMR (125 MHz, DMSO) δ 164.73, 164.70, 164.66, 153.76, 153.69,151.74, 151.67, 142.23, 142.17, 142.10, 133.08, 132.92, 132.76, 132.72,132.71, 132.68, 132.45, 130.75, 130.72, 130.69, 130.65, 130.34, 130.33,130.31, 123.78, 123.70, 123.67, 123.63, 123.60, 123.57, 121.64, 119.50, 119.37, 119.34, 119.21, 119.18, 84.11, 24.88;

[0089] Mass spectrometry characterization results:

[0090] ESI (m / z): [M+H] ＋ Calculated for C 21 H 17 BF8O4,496.11; found, 497.05.

[0091] VIII. Synthesis method of fluorine-containing ferroelectric nematic liquid crystal molecules:

[0092] In a three-necked flask, intermediate 7 (2 g, 4.03 mmol, 1 equivalent), intermediate 5 (2.05 g, 4.43 mmol, 1.1 equivalent), and potassium acetate (0.48 g, 4.84 mmol, 1.2 equivalent) were added to 75 mL of toluene and 15 mL of methanol. Under nitrogen protection, palladium dichloride bis(triphenylphosphine) (56.59 g, 80.62 mmol, 0.02 equivalent) was added. After the addition was complete, the reaction flask was transferred to a preheated oil bath and reacted at 120 °C for 4 hours. After the reaction was completed, the reaction system was poured into water, extracted with toluene, and the organic phase was washed three times with water. Anhydrous sodium sulfate was added to the organic phase for drying. The mixture was filtered, and the solvent was evaporated under reduced pressure. The crude product was purified by column chromatography using ethyl acetate:petroleum ether = 1:10 as the eluent to obtain a pale yellow solid, named ETC-912, with a yield of 46.8%. The structural formula is as follows:

[0093] .

[0094] NMR characterization results:

[0095] Hydrogen spectrum: 1H NMR (500 MHz, DMSO) δ 8.42 (m, 5H), 7.72 (m, 3H), 7.50 (m,2H), 7.20 (m, 2H), 7.10 (p, 1H), 6.95 (m, 2H), 4.00 (d, 2H), 1.74 (p, 2H),1.53 (h, 2H), 0.98 (t, 3H);

[0096] Carbon spectrum: 13 C NMR (125 MHz, DMSO) δ 166.05, 166.03, 166.00, 164.73, 164.70,164.66, 159.95, 159.89, 157.94, 157.87, 156.53, 153.61, 153.54, 151.58,151.52, 144.88, 140.02, 139.96, 139.89, 138.25, 138.23, 138.21, 133.48,133.42, 133.35, 132.72, 132.45, 131.13, 130.97, 130.81, 130.75, 130.72, 130.69, 130.65, 130.34, 130.31, 130.08, 130.06, 130.03, 128.24, 128.22, 128.20, 127.85, 127.63, 127.03, 126.97, 126.91, 123.78, 123.67, 123.63, 123.60, 122.64, 121.64, 117.52, 117.36, 117.20, 116.86, 114.06, 114.04, 113.90, 113.88, 113.74, 113.72, 67.81, 31.13, 19.20, 13.78;

[0097] Mass spectrometry characterization results:

[0098] ESI (m / z): [M+H] ＋ Calculated for C 38 H 24 F 10 O5,750.15; found, 751.12.

[0099] Example of results.

[0100] (1) Thermodynamic properties test of novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912:

[0101] The thermodynamic properties of novel ferroelectric nematic liquid crystal molecules were tested using differential scanning calorimetry (DSC). Figure 18 The phase transition process of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 is shown at a heating / cooling rate of 10 °C / min. The solid line represents the first cooling curve, showing two phase transition peaks: at 170 °C, it transitions from the nematic phase to the ferroelectric nematic phase; when the temperature drops to 75 °C, it transitions from the ferroelectric nematic phase to the crystalline phase, i.e., crystallization occurs at 75 °C. The dashed line represents the heating curve, which also shows two phase transition peaks, corresponding to the melting point peak and the clearing point peak, respectively.

[0102] (2) Hysteresis loop test of novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912:

[0103] Hysteresis loops are an important basis for proving whether novel ferroelectric nematic liquid crystal molecules possess ferroelectric properties. Figure 19 The PE hysteresis loop diagram of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 in its ferroelectric nematic phase at 150 °C is shown. The saturation polarization of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 reaches 5.4 µC / cm. -2 In summary, the parallelogram-shaped hysteresis loop exhibited by the novel ferroelectric nematic liquid crystal molecules conforms to the properties of general ferroelectric materials, and its saturation polarization value is significant.

[0104] (3) Measurement of second harmonic nonlinear optical (SHG) signals:

[0105] To prove the existence of the ferroelectric nematic phase, second harmonic nonlinear optical (SHG) signal measurements were performed on novel ferroelectric nematic liquid crystal molecules. The variation of polarization intensity with temperature was derived from the intensity changes of the measured SHG signal. Figure 20 As shown, SHG signals were detected in the temperature range (75~170℃) corresponding to the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912, while no SHG signals were detected in the temperature range of the non-ferroelectric nematic phase, proving the existence of the ferroelectric nematic phase.

[0106] (4) Dielectric property testing of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912:

[0107] The specific method is to take two pieces with a 1cm diameter strip in the center. 2 Indium tin oxide (ITO) glass of the same conductive area was used to heat novel fluorine-containing ferroelectric nematic liquid crystal molecules prepared in the examples to a liquid crystal state, sandwiching them between corresponding ITO glass layers and connecting them in series with gold foil. This formed a dielectric measurement unit with an average electrode gap of 2 μm. The nodal performance of the liquid crystal molecules was tested, and the results are shown in […]. Figure 21The dielectric constant measured at 1 kHz can reach as high as 1.4 × 10⁻⁶ within a temperature range of 0–225 °C. 4 .

[0108] (5) Thermogravimetric analysis of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912:

[0109] Thermogravimetric analysis is used to determine the thermal decomposition temperature of ferroelectric nematic liquid crystal molecules. Figure 22 The thermogravimetric analysis diagram of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 shows that when the mass loss is 5%, the thermal decomposition temperature of the novel fluorine-containing ferroelectric nematic liquid crystal molecule ETC-912 is 290℃, indicating that the novel ferroelectric nematic liquid crystal molecule has excellent thermal stability.

[0110] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A fluorine-containing ferroelectric nematic liquid crystal molecule, characterized in that, It has the following structure: 。 2. An application of the fluorine-containing ferroelectric nematic liquid crystal molecule as described in claim 1 in the field of optoelectronic materials.

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