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Method for preparing single-layer cholesteric liquid crystal film through elution/refilling technology and application of single-layer cholesteric liquid crystal film

A cholesteric liquid crystal, refilling technology, applied in the directions of instruments, optics, optical components, etc., can solve the problems of affecting the transmittance of the system, narrow reflection bandwidth, single-layer cholesteric liquid crystal film, etc., to avoid adverse effects. , the production process is simple, the effect of rich material sources

Active Publication Date: 2020-01-24
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Single-layer cholesteric liquid crystal films often have only a single reflection peak and narrow reflection bandwidth, which is not enough for some applications
When stacking multiple layers of thin films, the sudden change in refractive index between the thin films will significantly affect the transmittance of the system.

Method used

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  • Method for preparing single-layer cholesteric liquid crystal film through elution/refilling technology and application of single-layer cholesteric liquid crystal film
  • Method for preparing single-layer cholesteric liquid crystal film through elution/refilling technology and application of single-layer cholesteric liquid crystal film
  • Method for preparing single-layer cholesteric liquid crystal film through elution/refilling technology and application of single-layer cholesteric liquid crystal film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Fabrication of the liquid crystal cell: place the cleaned indium tin oxide (ITO) glass in a drying oven at 60° C. for 3 hours to dry. Add 3 g of polyvinyl alcohol (PVA) white solid particles into 97 mL of deionized water, stir magnetically, and slowly heat to 90° C. until all of them dissolve to obtain a 3% PVA solution. Use a homogenizer to coat the ITO glass with an initial speed of 600r / min for 10s and a high speed of 2000r / min for 30s, then heat-treat the glass substrate coated with the PVA polymer film at a temperature of 90°C for 120min. Use a flannel cloth to perform 3 times of directional rubbing on the side coated with the PVA orientation layer, avoiding excessive force as much as possible. The above two glass substrates were combined, the rubbing direction was antiparallel, and a PET film with a thickness of 50 μm was used as a spacer to make a liquid crystal cell.

[0038] Mix the nematic liquid crystal SLC1717, the chiral compound R5011, the polymerizable m...

Embodiment 2

[0052] Nematic liquid crystal E7, chiral compound S811, polymerizable monomer RM257 and photoinitiator 184 were uniformly mixed in a mass ratio of 54:25:20:1, and poured into a plane-aligned liquid crystal cell at room temperature.

[0053] S811 chemical structural formula:

[0054]

[0055] RM257 chemical structural formula:

[0056]

[0057] Photoinitiator 184 chemical structural formula:

[0058]

[0059] After the system is stable, use 365nm ultraviolet light to irradiate the liquid crystal cell, and the ultraviolet irradiance is 4mW / cm 2 , the irradiation time is 20 minutes, so that the polymerizable monomers are cured and cross-linked to form a network.

[0060] Soak the polymerized sample in a mixture of acetone and chloroform to submerge the liquid crystal cell, store it for 5 days, take it out, place it in a drying oven at 60°C for 4 hours, and obtain a liquid crystal cell containing a polymer network.

[0061] Mix nematic liquid crystal E7, chiral compoun...

Embodiment 3

[0063] Nematic liquid crystal SLC7011, chiral compound R1011, polymerizable monomer LC242 and photoinitiator 907 were mixed evenly at a mass ratio of 73:8:18:1, and poured into a plane-oriented liquid crystal cell at room temperature.

[0064] Chemical structural formula of R1011:

[0065]

[0066] LC242 chemical structural formula:

[0067]

[0068] Chemical structural formula of photoinitiator 907:

[0069]

[0070] After the system is stable, use 365nm ultraviolet light to irradiate the liquid crystal cell, and the ultraviolet light irradiance is 5mW / cm 2 , the irradiation time is 20 minutes, so that the polymerizable monomers are cured and cross-linked to form a network.

[0071] Soak the polymerized sample in cyclohexane to submerge the liquid crystal cell, store it for 5 days, take it out, place it in a drying oven at 60°C for 6 hours, and obtain a liquid crystal cell containing a polymer network.

[0072] Mix nematic liquid crystal SLC7011, chiral compound R...

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Abstract

The invention provides a method for preparing a single-layer cholesteric liquid crystal film by using an elution / refilling technology. The method comprises the following steps: uniformly mixing a nematic liquid crystal, a chiral compound, a polymerizable monomer and a photoinitiator according to a certain mass ratio to prepare a cholesteric liquid crystal composite system with a specific screw pitch; performing light irradiation polymerization on the composite system; then washing out small-molecular liquid crystals, chiral compounds and unreacted polymerizable monomers by using an organic solvent so as to obtain a polymer network with a spiral structure; re-mixing cholesteric liquid crystal systems with different screw pitches, and filling the polymer network with the obtained mixture; and carrying out polymerization again after stabilization so as to obtain the single-layer cholesteric liquid crystal film with special reflection performance. The method has the advantages of simple preparation process, flexible operation, rich material sources, low material price, wide application range and the like.

Description

technical field [0001] The invention belongs to the application field of functional materials and provides a method for preparing a single-layer cholesteric phase liquid crystal film with a reflective band memory function by using a washing-out / refilling technology. The material can be widely used in the fields of light-enhancing films, gratings, laser protection, optical devices, sensors, and the like. Background technique [0002] Liquid crystal is a special form of matter in nature. Liquid crystal has the optical anisotropy of crystal and the flow property of liquid. It is a low-dimensional and ordered fluid. The centroid of the liquid crystal molecules is disordered (the crystal is ordered), and its director is ordered (the ordinary liquid is disordered), so the liquid crystal is an optically anisotropic material sensitive to external fields. Because of this special structure, liquid crystals can modulate light, and thus are widely used in the display field. The choles...

Claims

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Application Information

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IPC IPC(8): C08F122/20C08F2/48C08K5/156C08K5/10C08J5/18C08L35/02G02F1/1335G02B5/08
CPCC08F2/48C08F122/20C08J5/18C08J2335/02C08J2435/02C08K5/10C08K5/156G02B5/0808G02F1/133553
Inventor 曹晖张冬冬赵丽敏甘萍杨洲王冬何万里
Owner UNIV OF SCI & TECH BEIJING
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