Liquid crystal thin film having intelligent information encryption function, preparation method therefor, and use thereof

Abstract

A liquid crystal thin film having an intelligent information encryption function, a preparation method therefor, and a use thereof. The liquid crystal thin film comprises two transparent substrates which are arranged in parallel and a composite functional layer between the transparent substrates; the composite functional layer comprises a honeycomb polymer matrix and liquid crystals filled in pores of the polymer matrix; a polymer network is provided in each liquid crystal; and the distribution densities of the polymer networks in different areas of the liquid crystal thin film are different, such that the liquid crystal thin film can reversibly display an information pattern that disappears (or appears) when powered on and appears (or disappears) when powered off, or can reversibly display an information pattern that disappears (or appears) at a low temperature and appears (or disappears) at a high temperature. The liquid crystal thin film has different distribution densities of polymer networks in different areas, exhibits multiple responses to an electric field, a temperature, and a magnetic field, and can achieve visual effects in which an information pattern changes from invisible to visible or from visible to invisible, or changes color, thereby achieving an intelligent information encryption function.

Description

Liquid crystal film with intelligent information encryption function and preparation method and application thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of functional liquid crystal materials, in particular to a liquid crystal film with intelligent information encryption function and a preparation method and application thereof. BACKGROUND

[0002] At present, information patterning controllable materials are usually realized by using thermochromic, photochromic, electrochromic and other materials. Commonly used thermochromic materials include inorganic materials such as iodide, complex, organometallic compound, and organic materials such as spiropyran, fluorescent derivatives, polythiophene; photochromic materials include inorganic materials such as WO3, silver chloride, silver bromide, and organic materials such as spiropyran, captax, diarylethene, spirooxazine, azobenzene; electrochromic materials include metal oxides or hydrates such as WO3, MoO3, V2O5, Nb2O5, TiO2, platinum group (such as Pt, Ir, Os, Pd, Rh, Ru) metal oxides or hydrates such as NiO, IrO x , Rh2O3, and organic materials such as polythiophene, viologen, tetrathiafulvalene, metal phthalocyanine compounds, polyaniline, polypyrrole and polyethylenedioxythiophene. These materials can realize reversible information patterning function under external field. However, the above-mentioned color-changing materials have the problems of single function, complex processing of flexible thin film, etc.

[0003] Because liquid crystals have stimulus responsiveness to external fields such as electric field, magnetic field, heat, pressure and humidity, liquid crystal materials are an important class of organic thermochromic, photochromic and electrochromic materials. In thermochromic liquid crystal materials, temperature-sensitive color-changing devices such as thin film thermometers have been widely used, which are prepared by using the phase transition of smectic or crystalline-cholesteric phase of small molecule and polymer liquid crystal materials and the selective reflection characteristics of cholesteric phase liquid crystal to incident light. In photochromic liquid crystal materials, a series of photochromic materials have been developed by doping azobenzene, molecular motor and molecular switch into small molecule and polymer liquid crystals. In electrochromic liquid crystal materials, small molecule liquid crystal, polymer dispersed liquid crystal and polymer stable liquid crystal are all very good electrochromic materials. The above-mentioned liquid crystal materials can all realize reversible information patterning function under external field.

[0004] However, the liquid crystal material is used for preparing the information patterned controllable device, there are some insurmountable shortcomings. Among them, the small molecule liquid crystal is liquid, it is difficult to prepare large area flexible film; and the polymer liquid crystal has high viscosity, it is difficult to uniformly orient in large area, it is difficult to process into large area flexible film, and it is also difficult to switch pattern under external field. The polymer stabilized liquid crystal (PSLC) film can realize various patternization, but due to the low content of the polymer network, usually less than 10wt%, the peeling strength between the two substrates is low, and it is difficult to prepare large area flexible film. The polymer dispersed liquid crystal (PDLC) has high content of polymer matrix, high peeling strength between the two substrates, and can prepare large area flexible film, and has been widely used, but the porous polymer matrix in the PDLC cannot provide induction or stabilization for the orientation of the liquid crystal molecules, so the light regulation characteristics are single, the film is usually in light scattering state, and various patternization cannot be realized.

[0005] The existing reversible information patterned products cannot meet the diversified consumer demand, and new information patterned controllable products need to be developed. SUMMARY

[0006] The present application provides a liquid crystal film with intelligent information encryption function and a preparation method and application thereof, and aims to solve the problems of the existing liquid crystal information patterned controllable material, such as difficult to prepare film, difficult to switch pattern, and unable to realize various patternization.

[0007] In order to achieve the above purpose, the following technical scheme is adopted in the present application.

[0008] In a first aspect of the present application, a liquid crystal film with intelligent information encryption function is provided, comprising two layers of transparent substrates arranged in parallel and a composite functional layer between the transparent substrates; the composite functional layer comprises a honeycomb-shaped polymer matrix and liquid crystal filled in the pores of the polymer matrix, and the liquid crystal has a polymer network; the distribution density of the polymer network in different regions of the liquid crystal film is different, so that the liquid crystal film has reversible change information pattern which disappears (or displays) when an electric field is applied, and displays (or disappears) after the electric field is turned off; or reversible change information pattern which disappears (or displays) at low temperature, and displays (or disappears) at high temperature.

[0009] In some embodiments, the raw materials of the composite functional layer include flexible polymerizable monomer 5-60wt%, rod-shaped photopolymerizable monomer 0.5wt-15wt%, liquid crystal 20wt-94.4wt%, initiator 0.1wt%-5wt%, and spacer particles in an amount of 0.1-2wt% of the sum of the amounts of flexible polymerizable monomer, rod-shaped photopolymerizable monomer, liquid crystal mixture and initiator.

[0010] In some embodiments, the flexible polymerizable monomer comprises at least one of a flexible photopolymerizable monomer or a flexible thermal polymerizable monomer; wherein the flexible photopolymerizable monomer is capable of undergoing free radical polymerization or cationic polymerization under UV irradiation; the flexible thermal polymerizable monomer is capable of undergoing thermal polymerization under heating condition;

[0011] The rod-like photopolymerizable monomer is capable of undergoing free radical polymerization or cationic polymerization under UV irradiation;

[0012] The liquid crystal is a positive liquid crystal, a negative liquid crystal or a dual-frequency driving liquid crystal;

[0013] The initiator is a free radical initiator, a cationic photoinitiator or a thermal initiator;

[0014] The spacer particle is a styrene or silica microsphere with a diameter of 2 microns to 100 microns.

[0015] In some embodiments, the flexible photopolymerizable monomer comprises at least one of an acrylate monomer, an olefin monomer, a vinyl ether monomer or an epoxy monomer;

[0016] The flexible thermal polymerizable monomer comprises at least one of a mixture of an epoxy monomer and a thiol monomer, a mixture of an epoxy monomer and an amino monomer, a mixture of a vinyl ether monomer and a thiol monomer, a mixture of a vinyl monomer and a thiol monomer, or a mixture of an amino, hydroxyl, carboxyl or mercapto containing monomer and an isocyanate monomer;

[0017] The positive liquid crystal, the negative liquid crystal and the dual-frequency driving liquid crystal each comprise a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a liquid crystal with a smectic A phase-nematic phase phase transition or a liquid crystal with a smectic A phase-cholesteric phase phase transition;

[0018] The cholesteric liquid crystal is prepared by a cholesteric compound, a liquid crystal containing a cholesteric compound or a nematic liquid crystal and a chiral compound; the liquid crystal with a smectic A phase-cholesteric phase phase transition is prepared by a cholesteric compound, a liquid crystal containing a cholesteric compound or a liquid crystal with a smectic A phase-nematic phase phase transition and a chiral compound; the chiral molecule is S811, R811, S1011, R1011 or CB15;

[0019] The initiator comprises at least one of benzoin ethyl ether, benzophenone, thioxanthone, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, trimethylbenzoyl diphenylphosphine oxide, benzoin diethyl ether diazonium salt, diaryliodonium salt, triarylsulfonium salt, alkylsulfonium salt, iron arene salt, sulfonyloxy ketone, triarylsilyl ether, amine curing agent, dibutyl tin, tributyl tin or organolead compound.

[0020] In some embodiments, the rod-like photopolymerizable monomer has a structure according to any one of formulas (1)-(8) or a combination thereof:

[0021] wherein m is 1-20; n is 1-20; x is 1-2; y is 1-2;

[0022] E, Q is acrylate, epoxy, vinyl ether or olefinic functional group.

[0023] In some embodiments, the raw materials of the composite functional layer further include a dye;

[0024] The dye is an azo dye, an anthraquinone dye or a phthalocyanine dye.

[0025] In a second aspect of the present application, a method for preparing the above-mentioned liquid crystal film with intelligent information encryption function is provided, comprising:

[0026] S1, mixing the raw materials uniformly, adding between the substrates until filling the space between the substrates, and performing first curing by ultraviolet irradiation polymerization or / and thermal polymerization to obtain a film A;

[0027] S2, under the condition of orientation or non-orientation of the liquid crystal material molecules in the film A, irradiating the film A with ultraviolet light through a photomask at temperature T1 for t1 time to perform second curing, and obtaining a film B;

[0028] S3, under the condition of orientation or non-orientation of the liquid crystal material molecules in the film B, irradiating the film B with ultraviolet light at temperature T2 for t2 time to perform third curing, and obtaining a liquid crystal film with intelligent information encryption function.

[0029] In some embodiments, when the flexible polymerizable monomer is a flexible photopolymerizable monomer, the preparation method comprises:

[0030] mixing the raw materials uniformly to form a precursor liquid, adding the precursor liquid between the substrates until filling the space between the substrates to prepare a film, and performing first curing by irradiating the precursor liquid with ultraviolet light through a photomask at temperature T1 for t1 time under the condition of applying or not applying an electric field to the film, to obtain a film A;

[0031] performing second curing by irradiating the film A with ultraviolet light at temperature T2 for t2 time under the condition of orientation or non-orientation of the liquid crystal material molecules in the film A, to obtain a liquid crystal film with intelligent information encryption function.

[0032] In some embodiments, the orientation is specifically controlling the molecular orientation by applying an electric field to the film A or the film B;

[0033] and / or,

[0034] In S1, when the flexible polymerizable monomer is a flexible photopolymerizable monomer, ultraviolet irradiation polymerization is adopted, the temperature is -20-60℃, the time is 5-90s, and the ultraviolet light intensity is 0.5-300mW / cm 2 ; when the flexible polymerizable monomer is a flexible thermal polymerizable monomer, thermal polymerization is adopted, the temperature is 20-120℃, the time is 0.1-1h; when the flexible polymerizable monomer is a blend of a flexible photopolymerizable monomer and a flexible thermal polymerizable monomer, the flexible polymerizable monomer can be subjected to ultraviolet irradiation polymerization and thermal polymerization step by step;

[0035] and / or,

[0036] T1 is -20-60℃; t1 is 1-600s, and the ultraviolet light intensity is 0.5-300mW / cm 2 ;

[0037] and / or,

[0038] T2 is -20-60℃, t2 is 5-300s, and the ultraviolet light intensity is 0.5-300mW / cm 2 .

[0039] In a third aspect of the present application, the application provides the use of the liquid crystal film with the intelligent information encryption function or the liquid crystal film with the intelligent information encryption function prepared by the preparation method in a patterned controllable device.

[0040] Compared with the prior art, the present application has the following beneficial effects:

[0041] The liquid crystal film with the intelligent information encryption function has different distribution densities of polymer networks in different regions, has multiple responses to electric field, temperature and magnetic field, can realize rich information patterning customization, and can realize multiple visual effects such as information pattern from nothing to something, from something to nothing or color change, thereby having the information encryption function.

[0042] The preparation method can realize precise construction of the patterned network structure in the polymerization process by regulating the polymerization rate, diffusion rate and phase separation process, can prepare thin films with different patterned customization, is easy to process in a large area, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0044] Fig. 1 is a photograph of two masks used in the embodiments of the present application;

[0045] Fig. 2 is a diagram of the preparation process and working principle of the liquid crystal film of the present application; Fig. 2a is a diagram of the preparation process and working principle of the liquid crystal film with electrically controllable reversible information patterning function; Fig. 2b is a diagram of the preparation process and working principle of the liquid crystal film with temperature controllable reversible information patterning function;

[0046] Fig. 3 is a photograph of the liquid crystal film with electrically controllable reversible information encryption function of Example 1;

[0047] Fig. 4 is a photograph of the liquid crystal film with electrically controllable reversible information encryption function of Example 2 and Example 3;

[0048] Fig. 5 is a photograph of the liquid crystal film with temperature controllable reversible information encryption function of Example 4;

[0049] Fig. 6 is a photograph of the liquid crystal film with temperature controllable reversible information encryption function of Example 5;

[0050] Fig. 7 is a photograph of the liquid crystal film with electrically controllable reversible information encryption function of Example 7. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0052] In the following description of the embodiments of the present application, the terms "comprise", "contain", "have" and "include" and the like are open terms, i.e. meaning including but not limited to.

[0053] In the following description of the embodiments of the present application, the term "and / or" is used to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent the following three cases: A exists alone, B exists alone and A and B exist at the same time. Wherein A, B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0054] In the following description of the present embodiments, the term "at least one" means one or more and the term "multiple" means two or more. The term "at least one of the following (a)" or similar expressions refers to any combination of these terms, including a single term (a) or any combination of multiple terms. For example, "at least one of a, b or c", or "at least one of a, b and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be a single or multiple.

[0055] The terminology used in the present embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of the present embodiments. As used in the description of the present embodiments and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms as well, unless the context clearly indicates otherwise.

[0056] Those skilled in the art understand that in the following description of the present embodiments, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the present embodiments.

[0057] Those skilled in the art understand that the numerical ranges in the present embodiments should be understood as each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or stated range of intermediate values and any other stated value or intermediate value within the stated range is also included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0058] Unless otherwise defined, technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are concerned. In the event of conflict between the content of this specification and any incorporated document, the content of this specification controls.

[0059] In a first aspect, the application provides a liquid crystal film with intelligent information encryption function, comprising two layers of transparent substrates arranged in parallel and a composite functional layer between the transparent substrates; the composite functional layer comprises a honeycomb-shaped polymer matrix and a liquid crystal mixture filled in the pores of the polymer matrix, and the liquid crystal mixture has a polymer network; the distribution density of the polymer network in different regions of the liquid crystal film is different, so that the liquid crystal film has reversible changeable information patterns that disappear (or display) when an electric field is applied, and display (or disappear) after the electric field is removed; or reversible changeable information patterns that disappear (or display) at low temperature and display (or disappear) at high temperature.

[0060] Specifically, based on the different orientation of liquid crystal molecules in different regions, or the same orientation of liquid crystal molecules but different anchoring forces of the polymer network on the liquid crystal molecules, the light transmittance or light scattering intensity of different regions of the liquid crystal film changes to different degrees under the action of an external field (such as an electric field, a magnetic field or temperature), thereby generating the appearance or disappearance of information patterns; after the external field is removed, the liquid crystal film returns to the initial state.

[0061] In the application, the transparent substrate is a glass substrate, a PET substrate or a glass substrate / PET substrate with a transparent indium tin oxide (ITO) conductive coating.

[0062] In the application, the composite functional layer between the two substrates has a honeycomb-shaped porous structure of the polymer matrix, and the pores of the polymer matrix are filled with liquid crystal; the liquid crystal has a polymer network, and the polymer network fibers can be in non-oriented arrangement or oriented arrangement, such as vertical, parallel or spiral arrangement. It should be noted that the density of the polymer network in different regions of the liquid crystal film is different.

[0063] The liquid crystal film of the present application can present a pattern change process from nothing to something or from something to nothing under the action of electric field. For example, when the liquid crystal is selected as positive cholesteric phase liquid crystal and the polymer network is vertically oriented, the liquid crystal molecules in the area with high density of polymer fibers are anchored by the anchoring force of the polymer network, and the liquid crystal film is in transparent or semi-transparent state; the liquid crystal molecules in the area with low density of polymer fibers are in focal conic state of molecular orientation under the action of the polymer network, and the liquid crystal film is in light scattering state. When the light scattering state area of the liquid crystal film is small and the transparent or semi-transparent state area is large, the light scattering pattern is presented on the transparent or semi-transparent background; and when the transparent or semi-transparent state area of the liquid crystal film is small and the light scattering state area is large, the transparent or semi-transparent pattern is presented on the light scattering background. When the liquid crystal film is powered on, the liquid crystal in the area with low density of polymer fibers is vertically oriented and presents transparent state, the light scattering area disappears, the whole liquid crystal film presents transparent state, and the information pattern disappears; when the power is off, the liquid crystal molecules in the area with low density of polymer fibers present focal conic state of molecular orientation and light scattering state, and the information pattern reappears; and the liquid crystal film further realizes the reversible information patterning function.

[0064] For example, when the liquid crystal is selected as negative liquid crystal or the liquid crystal is driven by double frequency, the liquid crystal film can realize the reversible information patterning function of pattern display when electric field is applied and pattern disappearance when electric field is off.

[0065] In the present application, when the liquid crystal is selected as liquid crystal with Smectic A-Cholesteric phase phase transition (SmA-LC) and the polymer network is vertically oriented, the liquid crystal film presents a pattern change process from nothing to something with temperature change. For example, when the liquid crystal with vertically oriented polymer network is selected as liquid crystal with Smectic A phase at low temperature and Cholesteric phase at high temperature, the liquid crystal molecules of Smectic A phase are vertically oriented at low temperature, and the liquid crystal film is in transparent state; the liquid crystal film is warmed to Cholesteric phase, the liquid crystal molecules in the area with high density of polymer fibers are anchored by the anchoring force of the polymer network, the liquid crystal molecules are still vertically oriented, and the liquid crystal film is in transparent state in the area; but in the area with low density of polymer fibers, the anchoring of the polymer network to the liquid crystal molecules is weak, the liquid crystal molecules of Cholesteric phase present focal conic state of molecular orientation, and the liquid crystal film is in light scattering state in the area. According to the size of the mask, the light scattering pattern can be displayed on the transparent background or the transparent information pattern can be displayed on the light scattering background with temperature rise, and the information pattern disappears with temperature decrease. Thus, the liquid crystal film presents reversible change of information pattern from nothing to something with temperature change.

[0066] In the present application, when the liquid crystal is selected to be a liquid crystal with a smectic A-cholesteric phase transition, the polymer network in a part of the film region is vertically oriented, and the fiber density of the polymer network is small. This part of the film is transparent at low temperature and is in a light scattering state at high temperature. The polymer network in another part of the film region is randomly oriented (non-oriented), the liquid crystal in this part is in a focal conic state of molecular orientation, and is anchored by the polymer network. The film is in a light scattering state at high and low temperatures. According to the size of the mask, information patterns can be presented in a transparent background or in a light scattering background. As the temperature rises, the transparent part becomes a light scattering state, the pattern disappears, and an information pattern change process from yes to no is presented.

[0067] As a preferred embodiment of the present application, the composite functional layer can further comprise a dye, such as an azo dye, an anthraquinone dye or a phthalocyanine dye. In this case, the liquid crystal film can present different colors, and the colors of different regions of the liquid crystal film change under power on / off or high / low temperature, giving the liquid crystal film a color reversible patterning function.

[0068] In the present application, the raw materials of the composite functional layer include 5-60 wt% of a flexible polymerizable monomer, 0.5-15 wt% of a rod-like photopolymerizable monomer, 20-94.4 wt% of a liquid crystal, 0.1-5 wt% of an initiator, and 0.1-2 wt% of spacer particles based on the total weight of the flexible polymerizable monomer, the rod-like photopolymerizable monomer, the liquid crystal mixture, and the initiator. In the present application, the spacer particles are preferably polystyrene microspheres.

[0069] In the present application, the flexible polymerizable monomer includes at least one of a flexible photopolymerizable monomer or a flexible thermal polymerizable monomer. The flexible photopolymerizable monomer can undergo free radical polymerization or cationic polymerization under ultraviolet light irradiation, and includes at least one of an acrylate monomer, an olefin monomer, a vinyl ether monomer or an epoxy monomer; the flexible thermal polymerizable monomer can undergo thermal polymerization under heating conditions, and includes at least one of a mixture of an epoxy monomer and a thiol monomer, a mixture of an epoxy monomer and an amino monomer, a mixture of a vinyl ether monomer and a thiol monomer, a mixture of a vinyl monomer and a thiol monomer, or a mixture of a monomer containing amino, hydroxyl, carboxyl or mercapto and an isocyanate monomer.

[0070] In the present application, the flexible polymerizable monomer is preferably hydroxypropyl methacrylate (HPMA), lauryl methacrylate (LMA), polyethylene glycol diacrylate (PEGDA600) or bisphenol A ethoxylate dimethacrylate (Bis-EMA15), and more preferably a mixture of HPMA, LMA, PEGDA600 or Bis-EMA15. The chemical formulas of the above four monomers are as follows:

[0071] In the present application, according to the performance requirements of the final device, the liquid crystal can be selected from positive liquid crystal, negative liquid crystal or dual-frequency driving liquid crystal. Among them, the positive liquid crystal, negative liquid crystal or dual-frequency driving liquid crystal can be selected from nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, liquid crystal with smectic A phase-nematic phase transition or liquid crystal with smectic A phase-cholesteric phase transition, such as positive nematic liquid crystal, negative cholesteric liquid crystal and the like.

[0072] Among them, the cholesteric liquid crystal of the present application can be prepared using cholesteryl compounds, liquid crystals containing cholesteryl compounds or nematic liquid crystals plus chiral compounds; the liquid crystal with smectic A phase-cholesteric phase transition can be prepared using cholesteryl compounds, liquid crystals containing cholesteryl compounds or nematic liquid crystals with smectic A phase-cholesteric phase transition plus chiral compounds.

[0073] Specifically, the chiral molecule can be selected from S811, R811, S1011, R1011 or CB15, etc. The amount of the chiral compound is 0.1-90wt% of the mass of the cholesteric liquid crystal or the liquid crystal with smectic A phase-cholesteric phase transition, preferably the amount is 0.1-4wt%. In the present application, the chiral compound is preferably S811 or CB15, and the chemical formula of S811 is as follows:

[0074] The rod-like photopolymerization monomer has a rigid structure, which can be subjected to free radical polymerization or cationic polymerization under ultraviolet light irradiation, or subjected to free radical polymerization and cationic polymerization under ultraviolet light irradiation; preferably, it is any one or a mixture of several of the structures represented by formula (1)-formula (8):

[0075] Among them, m is 1-20; n is 1-20; x is 1-2; y is 1-2;

[0076] E, Q is acrylate, epoxy, vinyl ether or olefinic functional group.

[0077] The preferred rod-like photopolymerization monomer of the present application is C6M, and its chemical formula is as follows:

[0078] In the present application, the initiator can be selected from a free radical initiator, a cationic photoinitiator or a thermal initiator. The free radical initiator includes at least one of benzoin ethyl ether, benzophenone, thioxanthone, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, trimethylbenzoyl, diphenyl phosphine oxide or benzoin diethyl ether; the cationic photoinitiator includes at least one of diazonium salt, diaryliodonium salt, triarylsulfonium salt, alkylsulfonium salt, iron arene salt, sulfonyloxy ketone or triarylsiloxane ether; and the thermal initiator includes at least one of amine curing agent, dibutyl tin, tributyl tin or organic lead compound, wherein the amine curing agent is preferably K-54 or DMP-30.

[0079] In the embodiment of the present application, the photoinitiator is preferably benzophenone dimethyl ketal, i.e. photoinitiator 651, and its chemical formula is as follows:

[0080] In the present application, the spacer particle is preferably polystyrene microspheres.

[0081] In a second aspect, the present application provides a preparation method of the liquid crystal film with the intelligent information encryption function, and the method comprises the following steps:

[0082] S1, uniformly mixing the raw materials, adding between the substrates until filling the space between the substrates, and performing first curing by ultraviolet irradiation polymerization and / or thermal polymerization to obtain a thin film A;

[0083] Specifically, under the action of ultraviolet irradiation and photoinitiator, the flexible photopolymerizable monomer is polymerized and cured by ultraviolet irradiation to form a honeycomb-shaped polymer matrix, and the liquid crystal is filled in the pores of the polymer matrix; a small amount of rod-shaped photopolymerizable monomer is polymerized and cured, and most of the rod-shaped photopolymerizable monomer is distributed in the liquid crystal. This is because the collision probability between the free radicals of the flexible polymerizable monomer is much greater than that between the free radicals of the rigid rod-shaped photopolymerizable monomer, so that during the first light curing, the flexible photopolymerizable monomer is mainly cured within a certain time.

[0084] When the flexible photopolymerizable monomer is a flexible thermal polymerizable monomer, the flexible thermal polymerizable monomer is polymerized and cured by heat to form a honeycomb-shaped polymer matrix, and the liquid crystal is filled in the pores of the polymer matrix; the rod-shaped photopolymerizable monomer is not polymerized and cured, and is distributed in the liquid crystal.

[0085] When the flexible photopolymerizable monomer is a flexible thermal polymerizable monomer, the temperature of the thermal polymerization is 20-120℃, and the time is 0.1-1h. 2 When the flexible photopolymerizable monomer is a flexible thermal polymerizable monomer, the temperature of the thermal polymerization is 20-120℃, and the time is 0.1-1h.

[0086] When the flexible polymerizable monomer is a blend of flexible photopolymerizable monomers and flexible thermopolymerizable monomers, the curing of the flexible polymerizable monomer can be carried out in steps of ultraviolet light irradiation polymerization and thermal polymerization.

[0087] S2, orienting or not orienting the liquid crystal molecules in the film A, irradiating the film A with ultraviolet light through the mask at temperature T1 for t1 time to carry out the second curing, obtaining film B;

[0088] Specifically, the rod-shaped photopolymerizable monomers can be aligned along the electric field direction with the liquid crystal molecules or aligned together with the liquid crystal molecules as the temperature changes by applying an electric field to the film A to control the orientation of the liquid crystal molecules. When the film A needs to be oriented, a mask is overlaid on the film A at temperature T1, and an electric field is applied to make the rod-shaped photopolymerizable monomers and the liquid crystal molecules in the film A form a certain orientation. The film A is irradiated with ultraviolet light through the mask to make the photopolymerizable monomers in the light-transmitting region of the mask polymerize, and the second curing is completed. The mask of the present application is shown in FIG. 1.

[0089] In the second curing, T1 is -20-60°C. According to the specific requirements of the customized pattern, t1 is 1-600s, and the ultraviolet light intensity is 0.5-300mW / cm 2 .

[0090] S3, orienting or not orienting the film B by applying an electric field to the film B, irradiating the film B with ultraviolet light at temperature T2 for t2 time to carry out the third curing, obtaining a liquid crystal film with intelligent information encryption function.

[0091] By applying an electric field to the film B to control the orientation of the molecules, the rod-shaped photopolymerizable monomers can be aligned along the electric field direction with the liquid crystal molecules or aligned together with the liquid crystal molecules as the temperature changes. When the film B needs to be oriented, an electric field is applied to the film B at temperature T2 to make the un-polymerized rod-shaped photopolymerizable monomers and the liquid crystal molecules form a certain orientation. The film B is irradiated with ultraviolet light to make the rod-shaped photopolymerizable monomers in the mask-shielded region in the second curing process polymerize, and the third curing is completed. In this process, T2 is -20-60°C; according to the specific requirements of the customized pattern, t2 is 5-300s, and the ultraviolet light intensity is 0.5-500mW / cm 2 .

[0092] Due to the different curing temperatures of the rod-shaped photopolymerizable monomers or the different contents of the remaining rod-shaped photopolymerizable monomers in the un-mask-shielded region and the mask-shielded region after the second light curing, the polymer network densities are different in the un-mask-shielded region and the mask-shielded region after the third light curing. The present application prepares polymer networks with certain orientation and different fiber densities in the light-transmitting region and the shielded region of the liquid crystal film by the second curing and the third curing.

[0093] When the application uses liquid crystal material with specific phase transition, in addition to using the above preparation method to prepare the target film, the second and third curing temperature T1 and T2 can also be controlled to control the molecular orientation of the rod-shaped photopolymerizable monomer in the liquid crystal and photopolymerizable monomer mixture during the second and third light curing process, thereby controlling the orientation of the formed polymer network fibers. At the same time, the different diffusion speeds of rod-shaped photopolymerizable monomer radicals at high and low temperatures and in different phases, combined with the use of masks, make the polymer network fibers in different regions have different densities.

[0094] In the liquid crystal film of the application, the polymer network orientation in the regions with different polymer network fiber densities can be the same or different.

[0095] In the application, when the flexible photopolymerizable monomer is a flexible photopolymerizable monomer, because the collision probability of the free radicals of the flexible photopolymerizable monomer is greater than that of the rod-shaped photopolymerizable monomer, when they coexist, the polymerization speed of the flexible photopolymerizable monomer is greater than that of the rod-shaped photopolymerizable monomer, so steps S1 and S2 in the above preparation method can be combined into one step; it can also be prepared by the following method:

[0096] Mixing each raw material uniformly to form a precursor liquid, adding the precursor liquid between the substrates until the space between the substrates is filled to prepare a thin film, under the condition of applying or not applying an electric field to the thin film, irradiating the precursor liquid with ultraviolet light through a photomask at temperature T1 for t1 time to perform the first curing, and obtaining thin film A;

[0097] Under the condition of orienting or not orienting the molecules of the liquid crystal material in the thin film A, irradiating the thin film A with ultraviolet light at temperature T2 for t2 time to perform the second curing, and obtaining a liquid crystal film with intelligent information encryption function.

[0098] In this case, T1 is -20-60℃, T2 is -20-60℃, t1 is 1-600s, t2 is 5-300s, and the intensity of ultraviolet light is 0.5-300mW / cm 2 .

[0099] The liquid crystal film of the present application, the preparation process and working principle are shown in Figure 2. When the liquid crystal used is positive cholesteric phase liquid crystal, the liquid crystal film is a liquid crystal film with electrically controlled reversible information patterning function, the preparation process and working principle are shown in Figure 2a. When no electric field is applied, in the area with low density of polymer network fibers, the anchoring effect of the polymer network on the liquid crystal pair is relatively small, the liquid crystal molecules form random orientation, and the liquid crystal film is in a scattering state; in the area with high density of polymer network fibers, the anchoring effect of the polymer network on the liquid crystal molecules is large, the liquid crystal molecules are vertically oriented, and the liquid crystal film is in a transparent state; at this time, the light scattering pattern is displayed on the transparent background, as shown in Figure 3; by controlling the size of the mask, the transparent pattern can also be displayed on the light scattering background, as shown in Figure 4. When an electric field is applied, the liquid crystal is vertically oriented, the whole liquid crystal film turns into a transparent state, and the pattern disappears. When the electric field is turned off, the pattern appears again.

[0100] The liquid crystal film of the present application, when the liquid crystal used is a liquid crystal material with a certain phase transition, such as a liquid crystal material with a smectic A-cholesteric phase transition, and the polymer network is vertically oriented, the liquid crystal film is a liquid crystal film with temperature-controlled reversible information patterning function, the preparation process and working principle are shown in Figure 2b. When the environmental temperature is lower than the phase transition temperature of the liquid crystal, the smectic A liquid crystal molecules are vertically oriented, and the whole film is in a transparent state. When the environmental temperature is higher than the phase transition temperature of the liquid crystal, in the area with relatively small density of polymer network fibers of the liquid crystal film, the anchoring effect of the polymer network on the liquid crystal is relatively small, the liquid crystal undergoes phase transition, and the film switches to a scattering state; while in the area with relatively large density of polymer network fibers of the liquid crystal film, the anchoring effect of the polymer network on the liquid crystal molecules is relatively large, when the liquid crystal molecules are heated to the cholesteric phase, the liquid crystal molecules are still vertically oriented, and the film is still in a transparent state; at this time, the pre-set light scattering pattern is displayed on the transparent background, as shown in Figure 5. By controlling the size of the mask, the transparent pattern can also be displayed on the light scattering background, as shown in Figure 6. When the environmental temperature is lower than the transition temperature, the whole film becomes transparent, and the pattern disappears.

[0101] The liquid crystal film of the present application has the function of intelligent information encryption, and can be used in information patterning controllable devices. The liquid crystal film displays (or does not display) information pattern before applying electric field, the information pattern disappears (or is displayed) after applying electric field, and the information pattern is displayed (or does not display) again after turning off the electric field; or, the liquid crystal film has no (or has) information pattern when the environmental temperature is lower than the phase transition temperature of the liquid crystal, and presents (or does not present) information pattern when the environmental temperature is higher than the phase transition temperature of the liquid crystal, and the information pattern disappears (or is displayed) again when the environmental temperature is lower than the phase transition temperature of the liquid crystal. By designing the shape and size of the mask to prepare areas with different light transmittance, the customization of specific information pattern on the liquid crystal film is realized, which has broad application prospects in the fields of consumer electronics and information encryption.

[0102] The application is further illustrated by the following examples.

[0103] Example 1

[0104] The present example provides a preparation method of a liquid crystal film with electrically controllable reversible information patterning function, the raw materials and the proportions are shown in Table 1:

[0105] Table 1 Raw material proportions of Example 1

[0106] Among them, the nematic liquid crystal (SLC-1717) and the chiral compound S811 are commercial products of Shijiazhuang Chengzhizhiyonghua Display Material Co., Ltd.

[0107] S1, mix the raw materials described in Table 1 uniformly, sandwiched between two layers of ITO conductive plastic film, irradiate the film with ultraviolet light with an intensity of 10 mW / cm 2 for 20 s at 15°C to initiate polymerization of most of the flexible photopolymerizable monomers, obtaining a film A with a honeycomb-shaped polymer matrix;

[0108] S2, place a customized mask on film A, apply an electric field to film A to make it turn into a transparent state, heat film A to 40°C, and irradiate film A with ultraviolet light with an intensity of 15 mW / cm 2 for 600 s, forming an area with a larger density of polymer network fibers in the light transmission area of the mask, obtaining film B;

[0109] S3, remove the mask and continue to apply the electric field, so that film B remains in a transparent state, and irradiate the film with ultraviolet light with an intensity of 5 mW / cm 2 for 180 s at 15°C, forming an area with a smaller density of polymer network fibers outside the area with a larger density of polymer network fibers that has been formed, obtaining a liquid crystal film with intelligent information encryption function.

[0110] The mask used in Example 1 is the mask on the right side of Figure 1, and the physical diagram of the liquid crystal film with intelligent information encryption function prepared is shown in Figure 3. When no electric field is applied, a light-scattering Huawei logo is presented on the transparent background, and after the electric field is applied, the whole film becomes transparent and the information pattern disappears.

[0111] Example 2

[0112] The present example provides a preparation method of a liquid crystal film with electrically controllable reversible information patterning function, the raw materials and the proportions are shown in Table 1:

[0113] S1, mix the raw materials described in Table 1 uniformly, sandwiched between two layers of ITO conductive plastic film, irradiate the film with ultraviolet light with an intensity of 10 mW / cm 2UV irradiation of the film 20s, to initiate the polymerization of most of the flexible photopolymerizable monomers, to obtain a film A with honeycomb-like polymer matrix;

[0114] S2, placing a customized mask on the film A, applying an electric field to the film A, to make the film change into transparent state, heating the film A to 40℃, using UV light with intensity of 15mW / cm 2 UV irradiation of the film A 600s, to form the area with higher density of polymer network fibers in the light transmission area of the mask, to obtain a film B;

[0115] S3, removing the mask, continuing to apply the electric field, to make the film B keep in transparent state, using UV light with intensity of 5mW / cm 2 UV irradiation of the film 180s, to form the area with lower density of polymer network fibers in the area outside the area with higher density of polymer network fibers, to obtain a liquid crystal film with intelligent information encryption function.

[0116] The mask used in Example 2 is the mask on the left side of Figure 1, and the actual picture of the liquid crystal film with intelligent information encryption function prepared in Example 2 is shown in Figure 4. When no electric field is applied, the background in the light scattering state presents transparent Huawei Logo, and after the electric field is applied, the whole film becomes transparent state and the information pattern disappears.

[0117] Example 3

[0118] The present embodiment provides a preparation method of a liquid crystal film with electrically controlled reversible information patterning function, and the raw materials and their proportions are shown in Table 1:

[0119] S1, mixing the raw materials described in Table 1 uniformly, sandwiching between two layers of ITO conductive plastic film, using UV light with intensity of 10mW / cm 2 UV irradiation of the film 20s, to initiate the polymerization of most of the flexible photopolymerizable monomers, to obtain a film A with honeycomb-like polymer matrix;

[0120] S2, placing a customized mask on the film A, applying an electric field to the film A, to make the film change into transparent state, heating the film A to 15℃, using UV light with intensity of 5mW / cm 2 UV irradiation of the film A 180s, to form the area with lower density of polymer network fibers in the light transmission area of the mask, to obtain a film B;

[0121] S3, removing the mask, continuing to apply the electric field, to make the film B keep in transparent state, using UV light with intensity of 15mW / cm 2 UV irradiation of the film 600s, to form the area with higher density of polymer network fibers in the area outside the area with lower density of polymer network fibers, to obtain a liquid crystal film with intelligent information encryption function.

[0122] The mask used in Example 3 is the mask on the right side of Figure 1, and the actual diagram of the liquid crystal film with the intelligent information encryption function prepared is shown in Figure 4. When no electric field is applied, the background in the light scattering state presents a transparent Huawei logo, and after the electric field is applied, the whole film becomes transparent, and the information pattern disappears.

[0123] Example 4

[0124] This embodiment provides a preparation method of a liquid crystal film with a temperature-controlled reversible patterning function, and the raw materials and their proportions are shown in Table 2:

[0125] Table 2 Raw material proportions of Example 3

[0126] Among them, the smectic-cholesteric phase transition liquid crystal (SmA-ChLC) is a liquid crystal material product SZYH-08A of Beijing Suzhou Yinghui Rainbow Film Material Technology Co., Ltd.

[0127] S1, mix the raw materials described in Table 2 uniformly, sandwiched between two layers of ITO conductive plastic film, irradiate the film with ultraviolet light with an intensity of 10 mW / cm 2 for 20 s at 15°C to initiate polymerization of most of the flexible photopolymerizable monomers, and obtain a film A with a honeycomb-shaped polymer matrix;

[0128] S2, place the customized mask on film A, apply an electric field to film A to make the film transition to a transparent state, heat film A to 40°C, and irradiate film A with ultraviolet light with an intensity of 15 mW / cm 2 for 600 s to form a region with a larger density of polymer network fibers in the light transmission area of the mask, and obtain a film B;

[0129] S3, remove the mask and continue to apply the electric field to keep film B in a transparent state, and irradiate the film with ultraviolet light with an intensity of 5 mW / cm 2 for 180 s at 15°C to form a region with a smaller density of polymer network fibers outside the region where the density of polymer network fibers is larger, and obtain a liquid crystal film with an intelligent information encryption function.

[0130] The mask used in Example 4 is the mask on the right side of Figure 1, and the actual diagram of the liquid crystal film with the intelligent information encryption function prepared is shown in Figure 5. At low temperature, the liquid crystal film is in a transparent state, and at high temperature, the Huawei logo pattern in the light scattering state is displayed on the transparent background.

[0131] Example 5

[0132] This embodiment provides a preparation method of a liquid crystal film with a temperature-controlled reversible patterning function, and the raw materials and their proportions are shown in Table 2:

[0133] S1, mix the raw materials described in Table 2 uniformly, sandwiched between two layers of ITO conductive plastic film, irradiate the film with ultraviolet light at an intensity of 10 mW / cm 2 for 20 s at 15°C to initiate polymerization of most of the flexible photopolymerizable monomers, obtaining film A with a honeycomb-shaped polymer matrix;

[0134] S2, place a customized mask on film A, apply an electric field to film A to make the film turn into a transparent state, heat film A to 40°C, and irradiate film A with ultraviolet light at an intensity of 15 mW / cm 2 for 600 s to form areas with a higher density of polymer network fibers in the light-transmitting areas of the mask, obtaining film B;

[0135] S3, remove the mask and continue to apply an electric field to keep film B in a transparent state, and irradiate film B with ultraviolet light at an intensity of 5 mW / cm 2 for 180 s at 15°C to form areas with a lower density of polymer network fibers in the areas outside the areas with a higher density of polymer network fibers that have been formed, obtaining a liquid crystal film with a smart information encryption function.

[0136] The mask used in Example 5 is the mask on the left side of Figure 1, and the actual picture of the liquid crystal film with a smart information encryption function prepared is shown in Figure 6. At low temperature, the liquid crystal film is in a transparent state, and at high temperature, it displays a transparent Huawei logo pattern in the background of a light scattering state.

[0137] Example 6

[0138] This example provides a method for preparing a liquid crystal film with a temperature-controlled reversible patterning function, and the raw materials and their proportions are shown in Table 2:

[0139] S1, mix the raw materials described in Table 2 uniformly, sandwiched between two layers of ITO conductive plastic film, irradiate the film with ultraviolet light at an intensity of 10 mW / cm 2 for 20 s at 15°C to initiate polymerization of most of the flexible photopolymerizable monomers, obtaining film A with a honeycomb-shaped polymer matrix;

[0140] S2, place a customized mask on film A, heat film A to 40°C, and irradiate film A with ultraviolet light at an intensity of 15 mW / cm 2 for 600 s to form areas with a higher density of polymer network fibers in the light-transmitting areas of the mask, obtaining film B that scatters light;

[0141] S3, remove the mask and apply an electric field to the film to keep the film transparent in the areas outside the areas with a higher density of polymer network fibers that have been formed, and irradiate the film with ultraviolet light at an intensity of 5 mW / cm 2UV irradiation of the film 180s, in the area outside the high polymer network fiber density has been formed larger, the formation of high polymer network fiber density smaller area, get the liquid crystal film with intelligent information encryption function.

[0142] The mask used in example 6 is the mask on the left or right side of figure 1. The film can present transparent pattern on the light scattering background at low temperature or present light scattering pattern on the transparent background, and the pattern disappears at high temperature, the whole film becomes light scattering state.

[0143] Example 7

[0144] This embodiment provides a two-step method for preparing a liquid crystal film with electrically controlled reversible patterning function, the raw materials and their proportions are shown in table 1:

[0145] S1, mix the raw materials described in table 1 uniformly, sandwiched between two layers of ITO conductive plastic film; apply electric field to the film, and place the customized mask on the ITO conductive plastic film, irradiate the film with UV light with intensity of 20 mW / cm 2 for 600s at 50℃, form the area with larger polymer network fiber density in the light transmission area of the mask, get film A;

[0146] S2, remove the mask, continue to apply electric field to keep the film A transparent, use light with intensity of 5 mW / cm 2 UV irradiation of the film 180s, in the area outside the high polymer network fiber density has been formed larger, the formation of high polymer network fiber density smaller area, get the liquid crystal film with intelligent information encryption function.

[0147] The mask used in example 7 is the mask on the right side of figure 1. The actual picture of the liquid crystal film with intelligent information encryption function prepared is shown in figure 7. When no electric field is applied, Huawei logo appears on the transparent background. After applying electric field, the whole film becomes transparent state and the information pattern disappears.

[0148] Example 8

[0149] This embodiment provides a two-step method for preparing a liquid crystal film with temperature controlled reversible patterning function, the raw materials and their proportions are shown in table 2:

[0150] S1, mix the raw materials described in table 2 uniformly, sandwiched between two layers of ITO conductive plastic film; apply electric field to the film, and place the customized mask on the ITO conductive plastic film, irradiate the film with UV light with intensity of 20 mW / cm 2 for 600s at 50℃, form the area with larger polymer network fiber density in the light transmission area of the mask, get film A;

[0151] S2, remove the mask, continue to apply electric field, make the film A keep transparent, use light intensity of 5mW / cm 2 UV irradiation film 180s, in the area where the density of polymer network fiber is relatively large, form the area where the density of polymer network fiber is relatively small, get the liquid crystal film with the function of intelligent information encryption.

[0152] The mask used in example 8 can be the mask on the left or right side of figure 1, and the liquid crystal film with the function of intelligent information encryption is prepared. At low temperature, the film can present light scattering pattern on the transparent background, or present transparent pattern on the light scattering background; at high temperature, the pattern disappears, and the whole film is in light scattering state.

[0153] Example 9

[0154] This example provides a two-step method for preparing a liquid crystal film with temperature-controlled reversible patterning function, and the raw materials and their proportions are shown in table 2:

[0155] S1, mix the raw materials described in table 2 uniformly, sandwiched between two layers of ITO conductive plastic film; place the customized mask on the ITO conductive plastic film, and use UV light with light intensity of 20mW / cm 2 irradiate the film for 600s at 50℃, form the area where the density of polymer network fiber is relatively large in the light transmission area of the mask, and get film A;

[0156] S2, remove the mask, apply electric field to the film, make the film A keep transparent in the area where the density of polymer network fiber is relatively large, use light intensity of 5mW / cm 2 UV irradiation film 180s, in the area where the density of polymer network fiber is relatively large, form the area where the density of polymer network fiber is relatively small, get the liquid crystal film with the function of intelligent information encryption.

[0157] The mask used in example 9 can be the mask on the left or right side of figure 1, and the liquid crystal film with the function of intelligent information encryption is prepared. At low temperature, the film can present light scattering pattern on the transparent background, or present transparent pattern on the light scattering background; at high temperature, the pattern disappears, and the whole film is in light scattering state.

[0158] Although the present application has been described in detail in the general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present application. Therefore, these modifications or improvements made on the basis of the spirit of the present application are within the scope of the present application.

Claims

1. A liquid crystal film with intelligent information encryption function, characterized in that, The liquid crystal film comprises two layers of transparent substrates arranged in parallel and a composite functional layer between the transparent substrates; the composite functional layer comprises a honeycomb-shaped polymer matrix and liquid crystal filled in the holes of the polymer matrix, and the liquid crystal has a polymer network therein; the distribution density of the polymer network in different regions of the liquid crystal film is different, so that the liquid crystal film has a reversible change information pattern which disappears (or displays) when an electric field is applied and displays (or disappears) after the electric field is removed; or a reversible change information pattern which disappears (or displays) at low temperature and displays (or disappears) at high temperature. The composite functional layer is prepared from raw materials including 5-60 wt% of flexible polymerizable monomers, 0.5-15 wt% of rod-shaped photopolymerizable monomers, 20-94.4 wt% of liquid crystal, 0.1-5 wt% of initiators, and 0.1-2 wt% of spacer particles based on the total weight of the flexible polymerizable monomers, the rod-shaped photopolymerizable monomers, the liquid crystal mixture, and the initiators.

2. The liquid crystal film with intelligent information encryption function according to claim 1, characterized in that, 3. The liquid crystal film with intelligent information encryption function according to claim 2, wherein: the flexible polymerizable monomers comprise at least one of flexible photopolymerizable monomers or flexible thermal polymerizable monomers; the flexible photopolymerizable monomers can be subjected to free radical polymerization or cationic polymerization under ultraviolet light irradiation; the flexible thermal polymerizable monomers can be subjected to thermal polymerization under heating conditions; the rod-shaped photopolymerizable monomers can be subjected to free radical polymerization or cationic polymerization under ultraviolet light irradiation; the liquid crystal is positive liquid crystal, negative liquid crystal, or dual-frequency driving liquid crystal; the initiators are free radical initiators, cationic photoinitiators, or thermal initiators; and the spacer particles are styrene or silica microspheres with a diameter of 2-100 microns.

4. The liquid crystal film with intelligent information encryption function according to claim 3, wherein: the flexible photopolymerizable monomers comprise at least one of acrylate monomers, olefin monomers, vinyl ether monomers, or epoxy monomers; the flexible thermal polymerizable monomers comprise at least one of a mixture of epoxy monomers and thiol monomers, a mixture of epoxy monomers and amino monomers, a mixture of vinyl ether monomers and thiol monomers, a mixture of vinyl monomers and thiol monomers, or a mixture of monomers containing amino groups, hydroxyl groups, carboxyl groups, or mercapto groups and isocyanate monomers; the positive liquid crystal, the negative liquid crystal, and the dual-frequency driving liquid crystal each comprise nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, liquid crystal with smectic A phase-nematic phase phase transition, or liquid crystal with smectic A phase-cholesteric phase phase transition; the cholesteric liquid crystal is prepared from cholesterols, liquid crystal containing cholesterols, or nematic liquid crystal and chiral compounds; the liquid crystal with smectic A phase-cholesteric phase phase transition is prepared from cholesterols, liquid crystal containing cholesterols, or liquid crystal with smectic A phase-nematic phase phase transition and chiral compounds; and the chiral molecules are S811, R811, S1011, R1011, or CB15. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The initiator includes at least one of benzoin ethyl ether, benzophenone, thioxanthone, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropanone, trimethylbenzoyl diphenylphosphine oxide, benzoin diethyl ether diazonium salt, diaryliodonium salt, triarylsulfonium salt, alkylsulfonium salt, iron arene salt, sulfonyloxy ketone, triarylsiloxane ether, amine curing agent, dibutyl tin, tributyl tin or organic lead compound.

5. The liquid crystal film with intelligent information encryption function according to claim 2, characterized in that, The rod-like photopolymerizable monomer has a structure represented by any one of Formulae (1) to (8) or a combination of several compositions: In the formula, m is 1-20; n is 1-20; x is 1-2; and y is 1-2. E and Q are acrylate, epoxy, vinyl ether or olefinic functional groups.

6. The liquid crystal film with intelligent information encryption function according to claim 2, characterized in that, The raw material of the composite functional layer further includes a dye. The dye is an azo dye, an anthraquinone dye or a phthalocyanine dye.

7. The method for preparing a liquid crystal thin film with intelligent information encryption function according to any one of claims 2-6, characterized in that, The method comprises the following steps: S1, mixing the raw materials uniformly, adding between the substrates until filling the space between the substrates, and performing first curing by ultraviolet irradiation polymerization or / and thermal polymerization to obtain a film A; S2, under the condition of liquid crystal material molecular orientation or non-orientation in the film A, irradiating the film A with ultraviolet light through a photomask at temperature T1 for t1 time to perform second curing, and obtaining a film B; S3, under the condition of liquid crystal material molecular orientation or non-orientation in the film B, irradiating the film B with ultraviolet light at temperature T2 for t2 time to perform third curing, and obtaining a liquid crystal film with intelligent information encryption function.

8. The preparation method according to claim 7, characterized in that, When the flexible polymerizable monomer is a flexible photopolymerizable monomer, the preparation method comprises: S1, mixing the raw materials uniformly to form a precursor liquid, adding the precursor liquid between the substrates until filling the space between the substrates to prepare a film, and performing first curing by irradiating the precursor liquid with ultraviolet light through a photomask at temperature T1 for t1 time under the condition of applying or not applying an electric field to the film, and obtaining a film A; S2, under the condition of liquid crystal material molecular orientation or non-orientation in the film A, irradiating the film A with ultraviolet light at temperature T2 for t2 time to perform second curing, and obtaining a liquid crystal film with intelligent information encryption function.

9. The preparation method according to claim 7, characterized in that, The orientation specifically controls the molecular orientation by applying an electric field to the film A or the film B; And / or, In S1, when the flexible polymerizable monomer is a flexible photopolymerizable monomer, ultraviolet light irradiation polymerization is adopted, the temperature is -20-60℃, the time is 5-90s, the ultraviolet light intensity is 0.5-300mW / cm 2 ; when the flexible polymerizable monomer is a flexible thermal polymerizable monomer, thermal polymerization is adopted, the temperature is 20-120℃, the time is 0.1-1h; when the flexible polymerizable monomer is a blend of a flexible photopolymerizable monomer and a flexible thermal polymerizable monomer, the flexible polymerizable monomer can be subjected to ultraviolet light irradiation polymerization and thermal polymerization step by step; And / or, T1 is -20 to 60°C; t1 is 1 to 600 seconds, and the intensity of the ultraviolet light is 0.5 to 300 mW / cm2 2 ; And / or, T2 is -20 to 60°C, t2 is 5 to 300 s, and the intensity of the ultraviolet light is 0.5 to 300 mW / cm2 2 .

10. Application of the liquid crystal film with intelligent information encryption function in claim 1-6 or the liquid crystal film with intelligent information encryption function prepared by the preparation method in claim 7-9 in a patterned controllable device.

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