阅读说明：本技术 液晶限域空间组装体微阵列的构建方法及其制备的液晶复合材料 (Construction method of liquid crystal limited domain space assembly microarray and liquid crystal composite material prepared by same ) 是由 李文 徐碧漪 王盈秋 彭磊 闵泽奇 陆东旭 于 2020-05-26 设计创作，主要内容包括：本发明公开了一种液晶限域空间组装体微阵列的构建方法及其制备的液晶复合材料,将液晶在限域空间形成有序组装体、并在二维平面排列成微阵列。本发明利用具有微腔阵列结构弹性体形成组装微腔,将液晶材料填充其间,在限域条件下形成一致或渐变液晶组装体阵列,通过腔体的结构和性质调控形成的液晶组装体的微观组织结构,通过添加高分子材料调节液晶的条纹间距,通过紫外光聚合实现对该液晶自组织结构的固定。本发明能在微米尺度制备和调控液晶组装体,突破了宏观方法在液晶结构精密构建上局限,获得的组装体阵列各个单元规整一致,适合生产应用。本发明所得液晶组装体阵列的微观光学结构,在非线性光学器件、智能传感器应用上都具有重要价值。(The invention discloses a construction method of a liquid crystal limited space assembly microarray and a liquid crystal composite material prepared by the same. The invention utilizes the elastic body with the microcavity array structure to form an assembled microcavity, fills the assembled microcavity with the liquid crystal material, forms a consistent or gradually-changed liquid crystal assembly array under the condition of limited domain, regulates and controls the microstructure of the formed liquid crystal assembly through the structure and the property of the cavity, regulates the fringe spacing of liquid crystal through adding high polymer material, and realizes the fixation of the self-organization structure of the liquid crystal through ultraviolet polymerization. The invention can prepare and regulate the liquid crystal assembly in the micron scale, breaks through the limitation of a macroscopic method on the precise construction of a liquid crystal structure, and the obtained assembly array has regular and consistent units and is suitable for production and application. The microscopic optical structure of the liquid crystal assembly array obtained by the invention has important value in the application of nonlinear optical devices and intelligent sensors.)

1. A method for constructing a liquid crystal limited space assembly microarray is characterized by comprising the following steps: the method comprises the steps of forming an assembly microcavity by using an elastic body with a microcavity array structure, filling a liquid crystal material in the assembly microcavity, forming a consistent or gradually-changed liquid crystal ordered assembly under the condition of a limited space, arranging the liquid crystal ordered assembly into a microarray on a two-dimensional plane, constructing a liquid crystal self-organization structure through the assembly microcavity, regulating and controlling the microstructure of the formed liquid crystal ordered assembly, regulating the fringe spacing of liquid crystals by adding a high polymer material, and fixing the liquid crystal self-organization structure through subsequent ultraviolet photopolymerization to obtain the liquid crystal composite material with the liquid crystal assembly array.

2. The method for constructing a liquid crystal confined space assembly microarray of claim 1, wherein: the elastomer with the microcavity array structure is a PDMS elastomer with the microcavity array structure.

3. The method for constructing a liquid crystal confined space assembly microarray of claim 1, wherein: cellulose nanocrystal liquid crystal materials are used as host substrates.

4. The method for constructing a liquid crystal confined space assembly microarray of claim 1, wherein: and regulating and controlling the ordering of the liquid crystal material in the micro-nano scale space by adding additional macromolecules and polymers.

5. The method for constructing a liquid crystal confined space assembly microarray of claim 1, wherein: and adding a photo-induced crosslinking related reagent to perform a crosslinking reaction, so as to fix the spatial structure of the liquid crystal formed by self-assembly, thereby obtaining the liquid crystal composite material with the liquid crystal assembly array.

6. The method for constructing a liquid crystal confined space assembly microarray as claimed in claim 1, comprising the steps of:

a. filling and self-assembling cellulose nanocrystal liquid crystals in the microcavity array:

preparing a silicon rubber elastomer mold with a microcavity array, coating fluorinated ether on the surface of a chip, and simultaneously dropwise adding cellulose nanocrystals onto another substrate and uniformly coating; covering the silicon rubber mold with one face with the array microcavity downwards on the substrate coated with the liquid crystal from one side; standing for 1-60 minutes for liquid crystal assembly, adding liquid crystal liquid with macromolecules, high molecular polymers and other additives, and performing coating and standing operations according to the steps to obtain a liquid crystal assembly;

b. controlling the pitch of the liquid crystal assembly:

b1. for the liquid crystal assembly prepared in the step a, by changing the geometrical shape, the diameter and the height dimension of the microcavity array, any one of the following single-molecule materials or any mixture of multiple molecules is additionally added:

linear small molecule polymer PEGDA, alkoxy ether dendrimer material Et-G1-COOMe, Et-G1-OH, Et-G1-Cl, Et-G1-NH₂Et-G1(MAc), alkoxyether branched polymer Et-G1(MAc) -P;

b2. b1, adjusting the structure and arrangement of the liquid crystal, and regulating the pitch of the liquid crystal assembly to obtain a liquid crystal solution;

the pitch is increased by increasing the height of the microcavity array;

the screw pitch is increased and the regularity of an assembly is improved through an additional linear micromolecular polymer PEGDA;

reducing the pitch of the assembly below the phase transition temperature by adding an alkoxy ether dendrimer material Et-G1 (MAc);

the regularity of an assembly is reduced by increasing the pitch by adding an alkoxy ether dendritic polymer Et-G1(MAc) -P;

c. curing of the assembly in the microarray:

additionally adding a cross-linking agent and a photoinitiator into the liquid crystal solution prepared in the step b; after the assembly, the assembly array is cured by light initiation under the protection of inert gas by a light source, so that the liquid crystal composite material with the liquid crystal assembly array is obtained.

7. The method for constructing a liquid crystal confined space assembly microarray of claim 1, wherein: in the step b1, when the geometric shape, the diameter and the height of the microcavity array are changed, the diameter and the height of the microcavity array are regulated to be 10-100 μm respectively.

8. A liquid crystal composite having an array of liquid crystal assemblies, prepared by the method of constructing a liquid crystal confined space assembly microarray of claim 1.

Technical Field

The invention belongs to the field of manufacturing of high polymer material functional micro-nano devices, and relates to a method for realizing a liquid crystal induced self-assembly array in a confined space and regulating and controlling an assembly structure. Belongs to the field of micro-nano materials and devices, and also belongs to the field of nonlinear devices in optical devices.

Background

The liquid crystal is a substance state with both liquid fluidity and crystal order, and the German physicist OttoLehmann verifies the existence of the liquid crystal through the phase state change under a polarization microscope during the heating process of the cholesteryl benzoate. Liquid crystals are classified into nematic liquid crystals and smectic liquid crystals according to molecular arrangement structures. The long axes of the liquid crystal molecules of the nematic liquid crystal are parallel to each other, the molecules are arranged freely, the centers of gravity are distributed randomly, the viscosity is low, and the nematic liquid crystal is sensitive to the change of the external environment, is the earliest applied liquid crystal material and is generally used for various liquid vv4 display devices. Cholesteric liquid crystal is chiral nematic liquid crystal, and belongs to one of nematic liquid crystals. The liquid crystal molecules are flat and have a spiral structure, the long axes are parallel to each other, the long axes of the molecules between two adjacent layers have a tiny torsion angle, the molecules of each layer uniformly rotate along the direction of a normal line, and the whole structure of the liquid crystal has the spiral property due to continuous change. The distance between two adjacent layers when the helix is rotated 360 degrees is called the cholesteric pitch. The chiral nematic liquid crystal has special optical properties of dichroism, selective light scattering, optical rotation and the like of circularly polarized light, and is widely applied to the fields of liquid crystal templates, optical sensors, chiral resolution, chiral catalysis, optical anti-counterfeiting materials and the like.

The performance of liquid crystal devices depends on the spatial arrangement of the liquid crystals, and therefore the construction of an orderly controllable liquid crystal assembly is the basis for achieving specific functions. The liquid crystal device with a certain structure is constructed on a microscopic scale, and a plurality of special properties which are not possessed by the macroscopic scale, particularly large specific surface area, obvious boundary effect, size enhancement effect, environmental sensitivity and the like can be brought, so that a large development space is provided for developing the performance and application of the liquid crystal device. For example, the Kumacheva topic group can realize concentric circle type and parallel line type light field reconstruction by constructing cholesteric liquid crystal globules with controllable structures through liquid crystal droplets. However, the prior art work in this area is still limited to the droplet-type geometric boundary conditions, and lacks flexible control over boundary structure and performance. On the other hand, it is also difficult to construct spatially ordered arrays of assemblies, the latter being critical for exerting the clustering effect. For example, the Capasso subject group of Harvard university realizes the precise modulation of light which is difficult to achieve by a macro lens through an optical lens gradual change array with a micro-nano structure, namely an optical super lens. But the materials currently used by this type of technology are limited to homogeneous materials. Finally, as a functional device, a certain curing means is required to cure the material, so as to avoid the damage of partial structural balance caused by the instability of the space state, and therefore, the curing of the assembly structure is also an important goal of technical development.

In summary, it is necessary to develop the fabrication technology of the arrayed local self-assembled liquid crystal structure. However, the research on the limited domain space self-assembly of the liquid crystal is still in the early stage, the related technologies are very limited, the search for the arraying technology is not yet available, and the technology in the aspect of urgent development lays a foundation for functional development.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to overcome the defects in the prior art and provide a method for constructing a liquid crystal limited space assembly microarray and a liquid crystal composite material prepared by the same. Cholesteric liquid crystals, here prepared using a Cellulose Nanocrystalline (CNC) material, as the essential component, form such assemblies characterized by: the liquid crystal forms a blending system with macromolecules and polymers, self-assembly is carried out in microcavity arrays with different sizes prepared from silicon rubber elastomer materials, and regulation and control of liquid crystal pitch and immobilization of liquid crystal space order can be realized through condition control.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

a method for constructing a liquid crystal limited space assembly microarray comprises the steps of forming an assembly microcavity by utilizing an elastic body with a microcavity array structure, filling liquid crystal materials in the assembly microcavity, forming consistent or gradually-changed liquid crystal ordered assemblies under the condition of limited space, arranging the liquid crystal ordered assemblies into the microarray on a two-dimensional plane, constructing a liquid crystal self-organization structure through the assembly microcavity, regulating and controlling the microstructure of the formed liquid crystal ordered assemblies, regulating the fringe spacing of liquid crystals by adding high polymer materials, and fixing the liquid crystal self-organization structure through subsequent ultraviolet photopolymerization to obtain the liquid crystal composite material with the liquid crystal assembly array.

The elastomer having the microcavity array structure is preferably a PDMS elastomer having a microcavity array structure.

The cellulose nano-crystal liquid crystal material is preferably used as a main substrate and has good biocompatibility.

Preferably, the order of the liquid crystal material in the micro-nano scale space is regulated and controlled by adding extra macromolecules and polymers.

Preferably, the spatial structure of the liquid crystal formed by self-assembly is fixed by adding a crosslinking agent to initiate crosslinking by light, and the liquid crystal composite material having the liquid crystal assembly array is formed by curing and crosslinking.

As a preferred technical scheme of the invention, the method for constructing the liquid crystal limited space assembly microarray comprises the following steps:

a. filling and self-assembling cellulose nanocrystal liquid crystals in the microcavity array:

preparing a silicon rubber elastomer mold with a microcavity array, coating fluorinated ether on the surface of a chip, and simultaneously dropwise adding cellulose nanocrystals onto another substrate and uniformly coating; covering the silicon rubber mold with one face with the array microcavity downwards on the substrate coated with the liquid crystal from one side; standing for 1-60 minutes for liquid crystal assembly, adding liquid crystal liquid with macromolecules, high molecular polymers and other additives, and performing coating and standing operations according to the steps to obtain a liquid crystal assembly;

b. controlling the pitch of the liquid crystal assembly:

b1. for the liquid crystal assembly prepared in the step a, by changing the geometrical shape, the diameter and the height dimension of the microcavity array, any one of the following single-molecule materials or any mixture of multiple molecules is additionally added:

linear small molecule polymer PEGDA, alkoxy ether dendrimer material Et-G1-COOMe, Et-G1-OH, Et-G1-Cl, Et-G1-NH₂Et-G1(MAc), alkoxyether branched polymer Et-G1(MAc) -P;

b2. b1, adjusting the structure and arrangement of the liquid crystal, and regulating the pitch of the liquid crystal assembly to obtain a liquid crystal solution;

the pitch is increased by increasing the height of the microcavity array;

the screw pitch is increased and the regularity of an assembly is improved through an additional linear micromolecular polymer PEGDA;

reducing the pitch of the assembly below the phase transition temperature by adding an alkoxy ether dendrimer material Et-G1 (MAc);

the regularity of an assembly is reduced by increasing the pitch by adding an alkoxy ether dendritic polymer Et-G1(MAc) -P;

c. curing of the assembly in the microarray:

additionally adding a cross-linking agent and a photoinitiator into the liquid crystal solution prepared in the step b; after the assembly, the assembly array is cured by light initiation under the protection of inert gas by a light source, so that the liquid crystal composite material with the liquid crystal assembly array is obtained.

In the step b1, when the geometrical shape, the diameter and the height of the microcavity array are changed, the diameter and the height of the microcavity array are regulated to be 10-100 μm respectively.

A liquid crystal composite material with a liquid crystal assembly array is prepared by the construction method of the liquid crystal confined space assembly microarray.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. the invention can break through the limitation of a macroscopic method and construct a liquid crystal assembly array on a micrometer scale;

2. the method has simple and feasible process, consistent height of each unit and suitability for actual production;

3. the method has low cost of raw materials, wide source of cellulose and good biocompatibility;

4. the liquid crystal assembly formed by the method has the advantages that the structure regulation and control are based on the micro-cavity structure and the additive, the regulation and control are accurate and easy to implement, the cost is low, and the liquid crystal assembly is suitable for popularization and use.

Drawings

FIG. 1 is a structural diagram of an alkoxy ether dendrimer and an alkoxy ether branched polymer according to the present invention.

FIG. 2 is a schematic diagram of the experimental principle of self-assembly of cellulose nanocrystals of the present invention in a microarray.

FIG. 3 is a diagram showing a self-assembly image of cellulose nanocrystal liquid crystal and a numerical statistical distribution diagram of cholesteric pitch P formed by cellulose nanocrystal self-assembly. FIGS. 3A-C) are self-assembled images of cellulose nanocrystal liquid crystals in microarrays with diameters of 20 μm and heights of 25 μm, 38 μm, and 50 μm, respectively, under a polarizing microscope; graph D) in fig. 3 is a statistical distribution of the values of the cholesteric pitch P formed by the self-assembly of cellulose nanocrystals in highly different confined microenvironments.

FIG. 4 is a numerical statistical distribution diagram of a self-assembly image of cellulose nanocrystal liquid crystals in a blending system and a cholesteric phase pitch P formed by liquid crystal self-assembly. Panel A in FIG. 4) self-assembly image of cellulose nanocrystal liquid crystals with 10 wt% PEGDA-575 blended system in a microarray 20 μm in diameter and 25 μm in height under a polarizing microscope; panel B of FIG. 4) is a numerical statistical distribution of the cholesteric pitch P formed by self-assembly of liquid crystals in different systems with or without PEGDA-575 added.

FIG. 5 is a self-assembly image under a polarizing microscope in a microarray having a height of 25 μm and a diameter of 20 μm. FIG. 5, Panel A) self-assembled image of monomer system with 10 wt% Et-G1(MAc) added at room temperature; FIG. 5, Panel B) self-assembled image of monomer system with 10 wt% Et-G1(MAc) added at 50 ℃; panel C of FIG. 5) self-assembled image of the polymer system at room temperature with 5 wt% addition of Et-G1(MAc) -P.

FIG. 6 is an SEM image. Wherein, the graph A) in FIG. 6 is a morphology characterization graph of the columnar microgel under SEM; FIG. 6, Panel B) is a SEM topography of an assembly with an actual structure of a bipolar striated texture; fig. 6, panel C) is an SEM topography representation of an assembly with an actual structure of concentric circular texture.

Detailed Description

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below: