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Cholesteric-phase liquid crystal material with color controlled by visible light

A cholesteric liquid crystal and visible light technology, applied in liquid crystal materials, organic chemistry, chemical instruments and methods, etc., can solve the problems of unfavorable on-demand design, limited application, high energy of ultraviolet light, etc.

Inactive Publication Date: 2019-01-08
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing technology of adjusting the color of cholesteric liquid crystals through the isomerization of ultraviolet light-responsive groups has two main defects: one is that the ultraviolet light has high energy, which is easy to cause damage to organisms, and at the same time, the penetration ability of ultraviolet light Weaker, which severely limits its application; second, the color of cholesteric liquid crystals generally changes within tens of minutes or even less after the light is terminated, and it is difficult to maintain long-term stability, which is not conducive to on-demand design

Method used

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  • Cholesteric-phase liquid crystal material with color controlled by visible light
  • Cholesteric-phase liquid crystal material with color controlled by visible light
  • Cholesteric-phase liquid crystal material with color controlled by visible light

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preparation example Construction

[0042] The preparation method of the cholesteric liquid crystal material of the present invention is as follows: 0.9 to 50 parts by weight of the unsubstituted azobenzene derivative, 0.1 to 50 parts by weight of the substituted chiral azobenzene derivative After being mixed with 30-99 parts of the nematic liquid crystal, it is packed into a liquid crystal cell with an alignment structure inside to form a cholesteric liquid crystal material.

[0043] The present invention also provides a preparation method of substituted chiral azobenzene derivatives. The preparation of the substituted chiral azobenzene derivatives can realize the selectivity of intermediate products by changing reaction conditions such as reaction time and solvent type Reaction, and then the substituted chiral azobenzene derivatives of different structures can be obtained under control, comprising the following steps:

[0044] (1) will be dissolved in the solvent A Mixed with the aqueous solution B of inorga...

Embodiment 1

[0055] (1) Dissolve 0.28g of 2-fluoroaniline in 10ml of tetrahydrofuran to obtain A, add A to 3.22g of sodium nitrite aqueous solution B at a rate of 1 μl, react under air atmosphere at 20°C, and react with magnetic stirring for 4.0 h, the product was extracted with water and dichloromethane, and the dichloromethane phase was spin-dried to obtain reaction intermediate 1;

[0056] (2) Dissolve 0.26g of reaction intermediate 1 in a mixed solvent of 10ml of acetonitrile and petroleum ether (volume ratio 1:1), then add 0.35g of (S)-(-)-1,1 ’ In -bin-dinaphthylamine, under an argon atmosphere at 25°C, the magneton was stirred for 0.5h, and after filtration and column chromatography, a substituted chiral azobenzene derivative was obtained, and its structural formula was:

[0057]

[0058] (3) 0.3g of the above substituted chiral azobenzene derivatives, 0.36g of unsubstituted azobenzene derivatives and 0.3g nematic liquid crystal (5CB) After mixing, pack into a liquid crystal ...

Embodiment 2

[0063] (1) Dissolve 0.51g of 2,6-dibromoaniline in 21ml of chloroform to obtain A, add A to 6.52g of potassium iodide aqueous solution B at a rate of 40μl, react under an argon atmosphere at 60°C, and mechanically Stirring and reacting for 26h, the product obtained a reaction intermediate after filtration and column chromatography;

[0064] (2) Dissolve 0.25g of the reaction intermediate in 10ml of carbon tetrachloride, then add 0.58g of (R)-(-)-1,1'-bin-dinaphthylamine, at 60°C under a nitrogen atmosphere , mechanically stirred for 120.0h, after filtration and column layer, a substituted chiral azobenzene derivative was obtained, and its structural formula was:

[0065]

[0066] (3) 0.002g substituted chiral azobenzene derivatives, 0.018g unsubstituted azobenzene derivatives and 1.98g nematic liquid crystal After mixing, it is packed into a liquid crystal cell with an alignment structure inside to form a cholesteric liquid crystal material;

[0067] (4) Use a light in...

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Abstract

The invention belongs to the technical field of light responsive materials, and particularly relates to a cholesteric-phase liquid crystal material with a color controlled by visible light. The invention discloses the cholesteric-phase liquid crystal material with the color controlled by the visible light. The cholesteric-phase liquid crystal material is prepared from the following raw materials in parts by weight: 30 to 99 parts of nematic liquid crystals, 0.9 to 50 parts of a non-substitutive azobenzene derivative and 0.1 to 50 parts of a substitutive chiral azobenzene derivative. The colorof the cholesteric-phase liquid crystal material has the visible light responsiveness; furthermore, after illumination is stopped, the color of the liquid crystal material can be stably maintained fora long time.

Description

technical field [0001] The invention belongs to the technical field of photoresponsive materials, and more specifically relates to a cholesteric liquid crystal material whose color can be regulated by visible light. Background technique [0002] The most direct and effective anti-counterfeiting technology is to distinguish the authenticity without any tools. For example, given a certain light stimulus, the observer can identify the material, hardness, texture, graphics, color, etc. by changing the angle or directly touching it. Security Information. The visual color-changing anti-counterfeiting technology obtained by using the ordered structure of liquid crystal and its polymer, photolithographic grating and multi-step polarization polymerization method belongs to this category. Because the color of this type of anti-counterfeiting material is easy to distinguish, and its color changes significantly under the light stimulation of time and space, therefore, the products made...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K19/02C09K19/36C09K19/60C07C245/10
CPCC07C245/10C09K19/02C09K19/36C09K19/601
Inventor 廖永贵赵东旭解孝林周兴平邱原王晶
Owner HUAZHONG UNIV OF SCI & TECH
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