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A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage and its preparation

A low driving voltage, dispersed liquid crystal technology, applied in liquid crystal materials, diffraction gratings, chemical instruments and methods, etc., can solve problems such as reducing the diffraction efficiency of holographic polymer dispersed liquid crystal gratings, increasing system viscosity and light scattering, and reducing grating diffraction efficiency. , to reduce the anchoring force, reduce light scattering, and increase the diffraction efficiency.

Active Publication Date: 2020-05-19
HUAZHONG UNIV OF SCI & TECH
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  • Description
  • Claims
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Problems solved by technology

Generally, the more regular the microstructure of the holographic polymer dispersed liquid crystal, the higher the diffraction efficiency, but the greater the anchor energy between the polymer and the liquid crystal, resulting in a higher driving voltage
[0003] At present, the methods to reduce the driving voltage of holographic polymer-dispersed liquid crystals are: (1) reduce the interfacial tension by introducing surfactants, thereby reducing the interfacial anchoring energy of the polymer layer to the liquid crystal [Polymer2004, 45, 7213-7218], this method is simple Effective, but it will reduce the diffraction efficiency of the grating; (2) Introduce inorganic nanoparticles with high low-frequency conductivity into the polymer-rich region, such as zinc sulfide nanoparticles, gold nanoparticles, graphene, etc. 【Mater.Chem.Front.2017 ,1,294-303], but the addition of nanoparticles will increase the viscosity and light scattering of the system, thereby reducing the diffraction efficiency of the holographic polymer dispersed liquid crystal grating; (3) introducing low surface energy polymers, such as fluoropolymers, silicon-containing polymers [Opt.Commun.2009,282,1541-1545], but the effect of this method is relatively limited, and the synthesis of polymers is difficult
How to reduce the driving voltage while improving the diffraction efficiency of holographic polymer-dispersed liquid crystals remains a challenge

Method used

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  • A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage and its preparation
  • A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage and its preparation
  • A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage and its preparation

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preparation example Construction

[0046] The holographic polymer dispersed liquid crystal of the present invention is uniformly mixed by photopolymerizable monomers, photoinitiators, liquid crystals, and thermal polymerization inhibitors, and then formed in situ under the holographic illumination of coherent lasers. The high diffraction efficiency of the present invention 1. The preparation method of holographic polymer dispersed liquid crystal with low driving voltage specifically includes the following steps:

[0047] (1) Put the components of the holographic polymer dispersed liquid crystal into a dark reactor, and mix at room temperature (20-30°C) to obtain a uniform mixed solution;

[0048] (2) Pour the mixed solution obtained in step (1) into a liquid crystal cell whose inner surface is covered with a conductive coating to obtain a package with a uniform thickness;

[0049] (3) Divide a laser beam into two coherent beams of equal intensity, expand the beam to form an interference field, and place the package de...

Embodiment 1

[0059] A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage, including 60wt.% photopolymerizable monomer, 1.95wt.% photoinitiator, 38wt.% liquid crystal and 0.05wt.% thermal polymerization inhibitor , The diffraction efficiency is 88%, the threshold voltage and saturation voltage are 3.4 and 6.7V / μm, respectively.

[0060] The photopolymerizable monomer is Si 2 The core thiol monomer (the structure is shown in formula (1), and n=6, R 1 =R 2 =C 5 H 11 , R 3 =R 4 =C 2 H 4 SH, R 5 =R 6 =CH 3 ), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol triacrylate, and pentaerythritol triallyl ether in a mixture of 3:2:2:2 in molar ratio, and the molar percentage of silicon-based monomer is 33.3%. The photoinitiator is Irgacure 184 / dibenzoyl peroxide (the mass ratio of the two is 1:10). The liquid crystal is E7, and the thermal polymerization inhibitor is p-benzoquinone.

[0061] The preparation method of the holographic polymer...

Embodiment 2

[0067] A holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage, including 69.3wt.% photopolymerizable monomer, 1.8wt.% photoinitiator, 30wt.% liquid crystal, and 0.1wt.% thermal polymerization resistance The diffraction efficiency is 94%, and the threshold voltage and saturation voltage are 1.4V / μm and 4.4V / μm, respectively.

[0068] The photopolymerizable monomer is SiO 1.5 The core thiol monomer (structure is shown in formula (1), and n=8, R 1 =R 2 =R 3 =R 4 =C 3 H 7 , R 5 =R 6 =R 7 =R 8 =C 3 H 6 According to the mixture of SH) and triallyl isocyanurate in a molar ratio of 3:4, the molar percentage of the silicon-based monomer is 42.9%. The photoinitiator is 3,3'-carbonyl bis(7-diethylamine coumarin) / N-phenylglycine (the mass ratio of the two is 1:2). The liquid crystal is P0616A, and the thermal polymerization inhibitor is tris(N-nitroso-N-phenylhydroxylamine) aluminum salt.

[0069] The preparation method of the holographic polym...

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Abstract

The invention belongs to the field of functional materials, and specifically relates to a holographic polymer dispersed liquid crystal electro-optical functional material with high diffraction efficiency and low driving voltage and a preparation method thereof. The holographic polymer dispersed liquid crystal comprises 25 to 78.8 parts of photopolymerizable monomers, 0.2 to 5 parts of a photoinitiator, 20 to 70 parts of liquid crystal and 0.05 to 2 parts of a thermal polymerization inhibitor, wherein the photopolymerizable monomers comprise a thiol monomer and an olefin monomer; and at least one selected from the group consisting of the thiol monomer and the olefin monomer is a silicon-based monomer. According to the invention, a sulfydryl or double-bonded silicon-based monomer is introduced into a formula for preparing the holographic polymer dispersed liquid crystal, and the introduction of the silicon-based monomer can significantly reduce the size of a liquid crystal microdroplet,so light scattering is reduced; meanwhile, silicon containing polymer has low surface energy, so the anchoring force to the liquid crystal is reduced, and the driving voltage of a device is decreased;thus, the holographic polymer dispersed liquid crystal with high diffraction efficiency and low driving voltage is obtained.

Description

Technical field [0001] The invention belongs to the field of functional materials, and specifically relates to a holographic polymer dispersed liquid crystal electro-optical functional material with high diffraction efficiency and low driving voltage and a preparation method thereof. Background technique [0002] Holographic polymer dispersed liquid crystals have an ordered microstructure of photonic crystals and have broad application prospects in 3D display, data storage, modulated lasers, high-end anti-counterfeiting and other fields. The two key parameters that determine its practical application are drive voltage and diffraction efficiency. Generally, the more regular the microstructure of the holographic polymer dispersed liquid crystal, the higher the diffraction efficiency, but the greater the anchoring energy between the polymer and the liquid crystal, resulting in higher driving voltage. [0003] The current methods for reducing the driving voltage of the holographic poly...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K19/54G02B5/18
Inventor 彭海炎陈冠楠解孝林廖永贵周兴平葛宏伟杨志方赵晔
Owner HUAZHONG UNIV OF SCI & TECH
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