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A kind of preparation method of chiral nematic structure broadband reflective film

A chiral nematic, broadband technology, applied in the field of material science

Active Publication Date: 2022-05-17
QILU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, by adjusting the helical axis of nanocellulose to change significantly, its helical pitch remains basically unchanged, and then obtain nanocellulose-polymer composite assembled films with arbitrarily adjustable reflection wavelength bandwidth, which has not been reported.

Method used

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  • A kind of preparation method of chiral nematic structure broadband reflective film
  • A kind of preparation method of chiral nematic structure broadband reflective film
  • A kind of preparation method of chiral nematic structure broadband reflective film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The preparation method of the broadband reflective composite film compounded with nano-cellulose and epoxy resin specifically comprises the following steps:

[0041] (1) Preparation of nanocellulose suspension: add cotton fiber to 64wt% concentrated sulfuric acid solution, heat and stir for hydrolysis, the heating temperature is 45° C., and the heating time is 1 hour. After the hydrolysis is completed, add water to dilute to terminate the hydrolysis, and take it out after standing The lower layer is precipitated, washed with water and centrifuged for 2-3 times, and then dialyzed to stabilize the pH value to obtain a cellulose suspension, which is evaporated and concentrated until the mass fraction of the cellulose suspension is 3%;

[0042] (2) Configure the dispersion system of epoxy resin in N,N-dimethylformamide. The mass fraction of the epoxy resin is 5%-35%.

[0043] (3) Take 10g of nanocellulose suspension prepared in step (1), get 0.2-10g of epoxy resin dispersi...

Embodiment 2

[0045] The preparation method of the nanocellulose-polyurethane broadband reflective composite film specifically comprises the following steps:

[0046] (1) Preparation of nanocellulose suspension: add microcrystalline fiber to 64wt% concentrated sulfuric acid solution, heat and stir for hydrolysis, the heating temperature is 45 ° C, and the heating time is 1 hour. After the hydrolysis is completed, add water to dilute to terminate the hydrolysis. After standing Take out the lower precipitate, wash with water and centrifuge 2-3 times, then dialyze to stabilize the pH value to obtain a cellulose suspension, then evaporate and concentrate until the mass fraction of the cellulose suspension is 3%;

[0047] (2) Water-based polyurethane can directly adopt commercially available products. The mass fraction of the waterborne polyurethane is 5%-35%.

[0048] (3) Take 10g of nanocellulose suspension prepared in step (1), take 0.2-10g of commercially available water-based polyurethane ...

Embodiment 3

[0055] The preparation method of the silicone-modified polyacrylate emulsion white light composite film using nanocellulose as a template specifically includes the following steps:

[0056] (1) Preparation of nanocellulose suspension: add microcrystalline fiber to 64wt% concentrated sulfuric acid solution, heat and stir for hydrolysis, the heating temperature is 45 ° C, and the heating time is 1 hour. After the hydrolysis is completed, add water to dilute to terminate the hydrolysis. After standing Take out the lower precipitate, wash with water and centrifuge 2-3 times, then dialyze to stabilize the pH value to obtain a cellulose suspension, then evaporate and concentrate until the mass fraction of the cellulose suspension is 3%;

[0057] (2) Configure silicone-modified acrylate emulsion: ① Take 20g of water, add 0.125g of sodium bicarbonate, 0.025g of sodium chloride, 0.25g of sodium lauryl sulfate, and 0.625g of OP-10 Emulsifier and 0.125g of sodium polyacrylate were mixed ...

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Abstract

The invention relates to a preparation method of a chiral nematic structure broadband reflective film. The invention is based on the self-assembly of nano-cellulose and polymers induced by the evaporation of water and organic solvents to prepare a composite film material. The composite material presents a polymer Cross-linked network structure with chiral nematic phase. Among them, the change of the helical axis of the chiral nematic structure at different angles is the main factor for the broadband reflection. The broadband reflective composite material with special structure prepared by the invention can be applied to optical fields such as filters, circular polarizers, circular polarized light detectors, sensors, and solar energy.

Description

technical field [0001] The invention belongs to the technical field of material science, and in particular relates to a preparation method of a chiral nematic structure broadband reflective film. Background technique [0002] Cellulose is the most abundant biopolymer in nature and can be prepared from a variety of natural resources, including plants, mantles, bacteria, etc. Treatment of cellulose fibers with acids or oxidizing agents produces negatively charged sulfonate or carboxylate groups. The electrostatic repulsion of surface charges enables cellulose nanocrystals to form a stable colloidal dispersion system in water, and can produce unique self-assembly properties under evaporation conditions: when the concentration is higher than the critical concentration, cellulose nanocrystals will spontaneously organize into a chiral nematic phase Lyotropic liquid crystals, this structure remains in the cellulose nanocrystalline film even after the water has completely evaporate...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J5/18C08L1/04C08L63/00C08L75/04C08L33/08
CPCC08J5/18C08J2301/04C08J2363/00C08J2401/04C08J2463/00C08J2475/04C08J2375/04C08J2333/08C08J2433/08
Inventor 苑再武张宇
Owner QILU UNIV OF TECH