Liquid crystal compound, liquid crystal composition and application thereof

A technology of liquid crystal compounds and liquid crystal compositions, which is applied in the direction of liquid crystal materials, chemical instruments and methods, waveguide devices, etc., can solve the problems of increased microwave dielectric loss, not large enough, affecting low-temperature performance and outdoor low-temperature work, and achieves Effect of reducing dielectric loss and reducing dielectric loss

Active Publication Date: 2019-05-17
WUHAN POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the main problems of liquid crystal materials used in microwave devices are: (1) due to insufficient Δn value and low dielectric constant (Δεr) in the high-frequency K-band, the amount of microwave phase shift is insufficient; (2) due to the stability of liquid crystal molecular structure (3) Due to the lack of high Δn value, low melting point liquid crystal solvent and nematic liquid crystal components, its low temperature performance and outdoor low temperature are affected Work
At the same time, the data of liquid crystal materials used in microwave devices reported abroad are mainly concentrated in the range of ≤19GHz, and there are few research reports on frequencies ≥20GHz; it is more meaningful to study the dielectric properties of the microwave k-band, especially the microwave frequency band above 25GHz

Method used

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  • Liquid crystal compound, liquid crystal composition and application thereof
  • Liquid crystal compound, liquid crystal composition and application thereof
  • Liquid crystal compound, liquid crystal composition and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] The present embodiment provides several preparation methods of compounds shown in formula I (refer to the synthetic route shown in formula (1), specifically as follows:

[0069] (1) Synthesis of 4-(1,2,2-trifluoro)vinylbromobenzene

[0070] Lithium diisopropylamide (LDA) reagent preparation [74] : In the 100mL three-neck flask equipped with mechanical stirring, 100mL constant pressure dropping funnel and low temperature thermometer, add diisopropylamine (0.2mol, 20.4g) and anhydrous THF (110mL), cool to-30 ℃, under N 2 Under protection, n-BuLi (0.2mol, 80mL) was slowly added dropwise, and the temperature was controlled at about -30°C. After the reaction was completed for 1 hour, it was sealed and stored at low temperature until use.

[0071] Add anhydrous ZnCl to another three-neck flask 2 (0.1mol, 13.8g), 60mL of anhydrous THF, under the protection of nitrogen, cool down to -70 ° C, pass into CF 3 CH 2 F (0.11mol, 12g), control the temperature at about -70°C, slowl...

Embodiment 2

[0109] The liquid crystal composition of Example 2 was prepared according to the compounds listed in the following table and their weight percentages. The specific method is: put each metering compound into a boron glass beaker, and then heat and melt it on a magnetic stirrer. After most of the mixture in the beaker is melted, put it into a magnetic rotor, stir the liquid crystal mixture evenly, heat it to the clearing point and then cool it down. to room temperature to obtain the liquid crystal composition M1.

[0110] The above liquid crystal mixture was put between the two substrates of the liquid crystal display for performance testing, and the test data are shown in the table below.

[0111] Table 5 Composition and dielectric properties of liquid crystal composition M1 group

[0112]

Embodiment 3

[0114] The liquid crystal composition of Example 3 was prepared according to the compounds listed in the following table and their weight percentages. The specific method is shown in Example 2 to obtain the liquid crystal composition M2.

[0115] The above liquid crystal mixture was put between the two substrates of the liquid crystal display for performance testing, and the test data are shown in the table below.

[0116] Table 6 Composition and dielectric properties of liquid crystal composition M2 group

[0117]

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Abstract

The invention discloses a difluoroethylene benzene liquid crystal compound, a liquid crystal composition and application thereof. The structure of the liquid crystal compound is as shown in a formulaI which is shown in the description, wherein n is an integer ranging from 1 to 8, and X1 and X2 are respectively and independently selected from H atoms, F atoms or Cl atoms. The liquid crystal composition is a nematic-phase liquid crystal material which meets the requirements of a microwave device and which is high in dielectric, low in loss and stable in low temperature performance, and the liquid crystal composition is capable of reducing dielectric loss of the microwave device, can be used as a liquid crystal material for a microwave phase shifter assembly and is suitable for the microwavephase shifter assembly.

Description

technical field [0001] The invention belongs to the technical field of liquid crystal materials for microwave devices, and more specifically relates to a liquid crystal compound, a liquid crystal composition and applications thereof. Background technique [0002] The research on the application of liquid crystals in microwave devices began at the end of the 20th century and developed rapidly at the beginning of this century; especially in recent years, it has attracted widespread attention from all over the world. Darmstadt University in Germany is a world leader in research in this field, and its research work covers important areas such as tunable filters, reconfigurable antennas, tunable frequency selectors, and tunable phase shifters. Currently, liquid crystal materials for display cannot meet the requirements of microwave devices because the value of Δn is less than about 0.22. The research on microwave liquid crystal devices has just started in China. [0003] At pre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K19/18C09K19/44H01P1/18
Inventor 张智勇关金涛李诗妍洪磊刘胜张海燕陈红梅汪相如赵怿哲高时汉扈映茹
Owner WUHAN POLYTECHNIC UNIVERSITY
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