Method for regulating optical performance of liquid crystals by using azobenzene

A technology using azobenzene and liquid crystal optics, applied in the field of photosensitive materials and liquid crystal materials, can solve the problem of high energy consumption

Inactive Publication Date: 2011-04-13
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional liquid crystal control system is composed of light and electricity. Although liquid crystal materials can be applied in optical fields such as optical storage, optical display, and optical switches, the energy consumption is relatively high.

Method used

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  • Method for regulating optical performance of liquid crystals by using azobenzene
  • Method for regulating optical performance of liquid crystals by using azobenzene
  • Method for regulating optical performance of liquid crystals by using azobenzene

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Azobenzene, binaphthyldiol and p-octylbiphenylcyanide (8CB) are mixed evenly according to the mass ratio of 10%: 1%: 89%, poured into a parallel-oriented liquid crystal cell, and at a room temperature of 21 degrees Celsius, The liquid crystal cell was irradiated with ultraviolet light with a wavelength of 365 nm (10 mW / cm2) for 480 seconds, and placed under natural light for 3 hours to recover.

[0029] Observe the changes of the liquid crystal texture with the ultraviolet-visible light under the polarizing microscope: ①Before the ultraviolet light, the texture of the mixed system is the fan-shaped texture of the smectic phase (such as Figure 3a As shown), the light transmittance of the liquid crystal cell is low at this time; ②, after using 365 nm ultraviolet light for 120 seconds, azobenzene with photoisomerization characteristics undergoes cis-trans isomerization (such as figure 2 As shown), affected by the isomerization of azobenzene molecules, the mixed system tr...

Embodiment 2

[0031] Mix azobenzene, binaphthyldiol and 8CB evenly according to the mass ratio of 5%: 4%: 91%, pour them into a parallel-oriented liquid crystal cell, and irradiate them with ultraviolet light with a wavelength of 365 nm at a room temperature of 21 degrees Celsius LCD box 480 seconds, Figure 5 It is shown that the transmittance spectrum changes with ultraviolet light by using a UV-visible spectrophotometer to test.

[0032] The test results show that after 60 seconds of ultraviolet light irradiation, the transmission peak of the mixed system red shifts from about 1250 nm to about 1400 nm; the transmission peak disappears after continuing to illuminate for 180 seconds, indicating that the photoisomerization of a small amount of azobenzene makes it The distance between the liquid crystal molecules on both sides increases, thereby changing the helical pitch of the cholesteric liquid crystal; when the photoisomerized azobenzene reaches a certain amount, the order of the liquid ...

Embodiment 3

[0034] Azobenzene, binaphthyldiol and 8CB are mixed evenly according to the mass ratio of 2%: 8%: 90%, poured into a parallel-oriented liquid crystal cell, and irradiated with ultraviolet light with a wavelength of 365 nm at a room temperature of 21 degrees Celsius 480 seconds in the liquid crystal box, and then placed under natural light for 3 hours to recover.

[0035] Figure 6 As shown, the initial state of the mixed system is a smectic phase, which turns into a nematic phase after 120 seconds of ultraviolet light irradiation, and the photoisomerization of azobenzene makes the liquid crystal change from a highly ordered smectic phase to a lower ordered one. The nematic phase, and the liquid crystal texture also changes from the fan-shaped texture of the smectic phase to the planar texture of the cholesteric phase, and the light transmittance increases accordingly. Due to the low content of azobenzene, the cholesteric phase is still maintained under continuous light, and t...

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Abstract

The invention relates to a method for regulating the optical performance of liquid crystals by using azobenzene and belongs to the field of application of photosensitive materials and liquid crystal materials. A matrix material consists of liquid crystal molecules, chiral molecules and photoresponsive azobenzene molecules. In the invention, the liquid crystal molecules, chiral molecules and photoresponsive azobenzene molecules are mixed in a certain proportion and filled into a liquid crystal box. The optical field control over the optical performance of the liquid crystal composite can be realized by regulating the chiral molecule content and azobenzene molecule content in the system. Different from the conventional methods for regulating the optical performance of the liquid crystals byelectric field, magnetic field and temperature, the method can realize optical field reversible regulation of the photopermeability and reflectivity of the liquid crystal box. The method can promote the better use of liquid crystal materials in fields of optical storage, optical display and optical switches.

Description

technical field [0001] The invention belongs to the field of photosensitive materials and liquid crystal materials, and uses the reversible azobenzene light field to control the optical properties of liquid crystals. Background technique [0002] Azobenzene compounds have become a kind of good light-controlling materials due to the special properties of trans-to-cis isomerization under ultraviolet light irradiation and cis-to-trans isomerization back reaction under visible light irradiation. When the azobenzene molecule undergoes photoisomerization, its molecular shape also changes. When the azobenzene molecule is in the trans structure, the shape is a rod-like structure; when the azobenzene molecule is in the cis structure, the shape is a curved structure. At present, azobenzene-based optical control materials have undergone a lot of basic research in optical storage, optical switches, optical displays, etc., which provides a broad application prospect for azobenzene in op...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K19/56
Inventor 王国杰张明智杨强杨槐张婷婷
Owner UNIV OF SCI & TECH BEIJING
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