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

Abstract

The invention relates to the technical field of functional liquid crystal materials, and discloses a liquid crystal film with an intelligent information encryption function and a preparation method and application thereof. The liquid crystal thin 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 polymer matrix and liquid crystals filled in holes of the polymer matrix, and a polymer network is arranged in the liquid crystals; the distribution densities of the polymer networks in different areas of the liquid crystal film are different, so that the liquid crystal film has reversible information patterns which disappear (or display) during power-on and display (or disappear) after power-off; or the reversible change information pattern disappears (or is displayed) at a low temperature and is displayed (or disappears) at a high temperature. The distribution densities of polymer networks in different areas of the liquid crystal film are different, multiple responses of an electric field, a temperature, a magnetic field and the like are achieved, the visual effect that information patterns exist from nothing, exist from existence to nothing or change colors can be achieved, and therefore the intelligent information encryption function is achieved.

Description

Technical Field

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

[0002] At present, information patterning and controllable materials are usually realized by using thermochromic, photochromic, electrochromic and other materials. Commonly used thermochromic materials include inorganic materials such as iodides, complexes, organometallic compounds, and organic materials such as spiropyran, fluorescent derivatives, polythiophene, etc.; photochromic materials include inorganic materials such as WO3, silver chloride, silver bromide, and organic materials such as spiropyran, fulgide, diarylethenes, spirooxazines, azobenzenes, etc.; 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 substances such as polythiophene and its derivatives, viologens, tetrathiafulvalene, metal phthalocyanine compounds, polyaniline, polypyrrole and polyethylenedioxythiophene. These materials can realize reversible information patterning function under the action of external field. However, the above color-changing materials have problems such as single function and complex flexible film processing.

[0003] Since liquid crystals are stimulus-responsive to external fields, such as electric fields, magnetic fields, 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, prepared by utilizing the smectic or crystalline-cholesteric phase transition of small molecule and polymer liquid crystal materials and the selective reflection characteristics of cholesteric phase liquid crystals to incident light have been widely used. In photochromic liquid crystal materials, a series of photochromic materials have been developed by adding azobenzene, molecular motors, and molecular switches to small molecule and polymer liquid crystals. In electrochromic liquid crystal materials, small molecule liquid crystals, polymer dispersed liquid crystals, and polymer stabilized liquid crystals are all very good electrochromic materials. The above-mentioned liquid crystal materials can all realize reversible information patterning functions under the action of an external field.

[0004] However, there are some insurmountable shortcomings in using the above-mentioned liquid crystal materials to prepare information patterned controllable devices. Among them, small molecule liquid crystals are in liquid state, making it difficult to prepare large-area flexible films; while polymer liquid crystals have high viscosity, making it difficult to uniformly orient over a large area, making it difficult to process into large-area flexible films, and it is also difficult to switch patterns under the action of an external field. Polymer-stabilized liquid crystal (PSLC) films can achieve various patterns, but due to their low polymer network content, usually less than 10wt%, the peel strength between the two substrates is low, making it difficult to prepare large-area flexible films. Polymer-dispersed liquid crystals (PDLCs) have a high polymer matrix content and high peel strength between the two substrates, so large-area flexible films can be prepared and have been widely used. However, the porous polymer matrix inside PDLC cannot provide induction or stabilization for the orientation of liquid crystal molecules, so its light regulation characteristics are single, and the film is normally in a light scattering state, and multiple patterns cannot be achieved.

[0005] Existing reversible information patterned products can no longer meet diverse consumer demands, and there is an urgent need to develop new information patterned controllable products. Summary of the invention

[0006] The present application provides a liquid crystal film with intelligent information encryption function and its preparation method and application, aiming to solve the problems of existing liquid crystal information patterning adjustable materials such as difficulty in film preparation, difficulty in pattern switching, and inability to achieve multiple patterning.

[0007] In order to achieve the above objectives, the present application adopts the following technical solutions.

[0008] In the first aspect of the present application, there is provided a liquid crystal film having an intelligent information encryption function, comprising two transparent substrates 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 the pores of the polymer matrix, wherein the liquid crystals have a polymer network; the distribution density of the polymer network in different regions of the liquid crystal film is different, thereby enabling the liquid crystal film to have a reversibly changing information pattern that disappears (or is displayed) when an electric field is applied and is displayed (or disappears) after the electric field is removed; or a reversibly changing information pattern that disappears (or is displayed) at low temperatures and is displayed (or disappears) at high temperatures.

[0009] In some embodiments, the raw materials of the composite functional layer include, by weight percentage, 5 to 60 wt % of flexible polymerizable monomers, 0.5 wt % to 15 wt % of rod-shaped photopolymerizable monomers, 20 wt % to 94.4 wt % of liquid crystals, 0.1 wt % to 5 wt % of initiators, and 0.1 to 2 wt % of spacer particles, which is the sum of the amounts of flexible polymerizable monomers, rod-shaped photopolymerizable monomers, liquid crystal mixture, and initiator.

[0010] In some embodiments, the flexible polymerizable monomer includes at least one of a flexible photopolymerizable monomer or a flexible thermal polymerizable monomer; wherein the flexible photopolymerizable monomer can be subjected to free radical polymerization or cationic polymerization under ultraviolet light irradiation; and the flexible thermal polymerizable monomer can be subjected to thermal polymerization under heating conditions;

[0011] The rod-shaped photopolymerizable monomer can undergo free radical polymerization or cationic polymerization under ultraviolet light irradiation;

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

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

[0014] The spacer particles are styrene or silicon dioxide microspheres, and the diameter thereof is 2 micrometers to 100 micrometers.

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

[0016] The flexible thermal polymerizable monomer includes 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;

[0017] The positive liquid crystal, negative liquid crystal and dual-frequency driven liquid crystal all include 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;

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

[0019] The initiator includes at least one of benzoin ethyl ether, benzophenone, thioanthrone, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylacetone, trimethylbenzoyl diphenyl phosphine oxide, benzoin diethyl ether diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron arene salt, sulfonyloxy ketone, triaryl siloxy ether, amine curing agent, dibutyl tin, tributyl tin or organic lead compound.

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

[0021]

[0022] Wherein, m is 1 to 20; n is 1 to 20; x is 1 to 2; y is 1 to 2;

[0023] E and Q are acrylate, epoxy, vinyl ether or olefin functional groups.

[0024] In some embodiments, 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.

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

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

[0027] S2, under the condition that the liquid crystal material molecules in the film A are oriented or not oriented, ultraviolet light is irradiated to the film A through a photomask at a temperature T1 for a time t1, and a second curing is performed to obtain a film B;

[0028] S3, under the condition that the liquid crystal material molecules in the film B are oriented or not oriented, the film B is irradiated with ultraviolet light for t2 time at temperature T2, and a third curing is performed to obtain 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 includes:

[0030] The raw materials are mixed evenly to form a precursor solution, and the precursor solution is added between the substrates until the space between the substrates is filled. Under the condition that the liquid crystal material molecules in the precursor solution are oriented or not oriented, ultraviolet light is irradiated to the precursor solution through a photomask for t1 time at a temperature T1 to perform the first curing to obtain a film A;

[0031] Under the condition that the liquid crystal material molecules in the film A are oriented or not oriented, the film A is irradiated with ultraviolet light for t2 time at temperature T2 for a second curing 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 film A or film B;

[0033] and / or,

[0034] In S1, when the flexible polymerizable monomer is a flexible photopolymerizable monomer, ultraviolet light irradiation polymerization is adopted, the temperature is -20 to 60°C, the time is 5 to 90 seconds, and the ultraviolet light intensity is 0.5 to 300 mW / cm 2 When the flexible polymerizable monomer is a flexible thermal polymerizable monomer, thermal polymerization is adopted, and the temperature is 20 to 120° C. and the time is 0.1 to 1 hour; 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 polymerized by ultraviolet radiation and thermal polymerization in steps;

[0035] and / or,

[0036] T1 is -20~60℃; t1 is 1~600s, UV intensity is 0.5~300mW / cm 2 ;

[0037] and / or,

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

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

[0040] Compared with the prior art, the beneficial effects of this application are:

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

[0042] The preparation method of the present application realizes the precise construction of patterned network structure during the polymerization process by regulating the polymerization rate, diffusion rate and phase separation process. It can prepare customized films with different patterns and is easy to process on a large area, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1The following are physical pictures of two masks used in the embodiments of the present application;

[0045] FIG2 is a diagram showing the preparation process and working principle of the liquid crystal film of the present application; Figure 2a The preparation process and working principle diagram of a liquid crystal film with electrically controlled reversible information patterning function; Figure 2b The preparation process and working principle diagram of a liquid crystal film with temperature-controlled reversible information patterning function;

[0046] Figure 3 This is a physical picture of the liquid crystal film with the electrically controlled reversible information encryption function of Example 1;

[0047] Figure 4 This is a physical picture of the liquid crystal film with the electrically controlled reversible information encryption function of Example 2 and Example 3;

[0048] Figure 5 This is a physical picture of the liquid crystal film with temperature-controlled reversible information encryption function of Example 4;

[0049] Figure 6 This is a physical picture of the liquid crystal film with temperature-controlled reversible information encryption function of Example 5;

[0050] Figure 7 This is a physical picture of the liquid crystal film with electrically controlled reversible information encryption function of Example 6. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with 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 of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0053] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0054] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0055] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

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

[0057] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0058] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0059] In the first aspect, the present application provides a liquid crystal film with intelligent information encryption function, comprising two parallel transparent substrates and a composite functional layer between the transparent substrates; the composite functional layer comprises a honeycomb polymer matrix and a liquid crystal mixture filled in the pores of the polymer matrix, the liquid crystal mixture having 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 can have a reversible information pattern that disappears (or appears) when an electric field is applied and is displayed (or disappears) after the electric field is removed; or a reversible information pattern that disappears (or appears) at low temperatures and is displayed (or disappears) at high temperatures.

[0060] Specifically, due to the different orientations of liquid crystal molecules in different regions, or the same orientations 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, magnetic field or temperature), resulting in the appearance or disappearance of the information pattern; after the external field is removed, the liquid crystal film returns to its initial state.

[0061] In the present 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 present application, the composite functional layer between the two substrates has a polymer matrix with a honeycomb porous structure, and the pores of the polymer matrix are filled with liquid crystals; the liquid crystal has a polymer network, and the polymer network fibers can be arranged in a non-oriented or oriented manner, such as vertical, parallel or spiral arrangement. It should be noted that the density of the polymer network in different areas 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 an electric field. Exemplarily, when the liquid crystal uses a positive cholesteric phase liquid crystal and the polymer network is vertically oriented, in the area of ​​the liquid crystal film where the polymer fiber density is high, the liquid crystal molecules are anchored by the anchoring force of the polymer network and are transparent or translucent; in the area of ​​the liquid crystal film where the polymer fiber density is low, the liquid crystal molecules are focal cone oriented under the action of the polymer network and are in a light scattering state. When the light scattering state area on the liquid crystal film is small and the transparent or translucent state area is large, a light scattering pattern is presented on a transparent or translucent background; and when the transparent or translucent state area of ​​the liquid crystal film is small and the light scattering state area is large, a transparent or translucent pattern is presented on a light scattering background. When the liquid crystal film is energized, the liquid crystal in the area with low polymer fiber density is vertically oriented and becomes transparent, the light scattering area disappears, the film as a whole becomes transparent, and the information pattern disappears; when the power is turned off, the liquid crystal molecules in the area with low polymer fiber density are oriented in a focal-conic state and become light-scattering, and the information pattern reappears; the liquid crystal film thus realizes the reversible patterning function.

[0064] For example, when negative liquid crystal is used or dual-frequency driven liquid crystal is used, the liquid crystal film can realize a reversible information patterning function in which a pattern is displayed when an electric field is applied and the pattern disappears after the electric field is removed.

[0065] In the present application, when the liquid crystal is selected to have a smectic A-cholesteric phase transition liquid crystal (SmA-LC) and the polymer network is vertically oriented, the liquid crystal film presents a pattern change process from nothing to something as the temperature changes. Exemplarily, when a liquid crystal with a vertically oriented polymer network and a smectic A phase at low temperature and a cholesteric phase at high temperature is selected, the smectic A phase liquid crystal molecules are vertically oriented at low temperature, and the liquid crystal film is transparent; the liquid crystal film is heated to the cholesteric phase, and in the area with high polymer fiber density, the liquid crystal molecules are anchored by the anchoring force of the polymer network, and the liquid crystal molecules are still vertically oriented, and the film is transparent in this area; but in the area with low polymer fiber density, the anchoring of the polymer network to the liquid crystal molecules is weak, and the cholesteric phase liquid crystal molecules are focal cone molecular orientation, and the film is in a light scattering state in this area. According to the size of the mask, as the temperature rises, a light scattering pattern can be displayed on a transparent background, or a transparent information pattern can be displayed on a light scattering background, so that the information pattern is realized from nothing to something; as the temperature decreases, the information pattern disappears. Thus, as the temperature changes, the film presents a reversible change of the information pattern from nothing to something.

[0066] In the present application, when the liquid crystal is selected to have a smectic A-cholesteric phase transition liquid crystal, the polymer network in a part of the film is vertically oriented, and the polymer network fiber density is relatively low. This part of the film is transparent at low temperatures and is in a light scattering state at high temperatures; the polymer network in another part of the film is randomly oriented (non-oriented), and this part of the liquid crystal is focal cone molecular orientation and is anchored by the polymer network. The film is in a light scattering state at both high and low temperatures. Depending on the size of the mask, a light scattering information pattern can be presented on a transparent background, or a transparent information pattern can be presented on a light scattering background. As the temperature rises, the transparent part becomes a light scattering state, and the pattern disappears, presenting a process of information pattern change from presence to absence.

[0067] As a preferred embodiment of the present application, the composite functional layer may further include dyes, such as azo dyes, anthraquinone dyes or phthalocyanine dyes. In this case, the liquid crystal film may present different colors, and the colors of different regions of the liquid crystal film may change when the power is on / off or at high / low temperatures, thereby giving the liquid crystal film a color reversible patterning function.

[0068] In the present application, the raw materials of the composite functional layer include, by weight percentage, 5-60 wt% of flexible polymerizable monomer, 0.5-15 wt% of rod-shaped photopolymerizable monomer, 20-94.4 wt% of liquid crystal mixture, 0.1-5 wt% of initiator, and 0.1-2 wt% of spacer particles in an amount equal to the sum of the amount of flexible polymerizable monomer, rod-shaped photopolymerizable monomer, liquid crystal, and 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 be subjected to 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 be subjected to thermal polymerization under heating conditions, and includes 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.

[0070] 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]

[0072] 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 driven liquid crystal. Among them, the positive liquid crystal, negative liquid crystal or dual-frequency driven 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, etc.

[0073] Among them, the cholesteric liquid crystal of the present application can be prepared using cholesterol compounds, liquid crystals containing cholesterol compounds, or nematic liquid crystals plus chiral compounds; the liquid crystals with smectic A phase-cholesteric phase transition can be prepared using cholesterol compounds, liquid crystals containing cholesterol compounds, or nematic liquid crystals with smectic A phase-nematic phase transition plus chiral compounds.

[0074] Specifically, the chiral molecule can be selected from commercial chiral compounds such as S811, R811, S1011, R1011 or CB15, and its usage is 0.1-90wt% of the mass of the cholesteric liquid crystal or the smectic A phase-cholesteric phase transition liquid crystal, and preferably its usage is 0.1-4wt%. In the present application, the chiral compound is preferably S811, and its chemical formula is as follows:

[0075]

[0076] The rod-shaped photopolymerizable monomer can undergo free radical polymerization or cationic polymerization under ultraviolet light irradiation, or can undergo free radical polymerization and cationic polymerization under ultraviolet light irradiation; it includes any one or a mixture of several of the structures shown in formula (1) to formula (8):

[0077]

[0078]

[0079] Wherein, m is 1 to 20; n is 1 to 20; x is 1 to 2; y is 1 to 2;

[0080] E and Q are acrylate, epoxy, vinyl ether or olefin functional groups.

[0081] The preferred rod-shaped photopolymerizable monomer in the present application is C6M, and its chemical formula is as follows:

[0082]

[0083] In the present application, the initiator can be selected from free radical initiators, cationic photoinitiators or thermal initiators. Among them, the free radical initiator includes at least one of benzoin ethyl ether, benzophenone, thioanthrone, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylacetone, trimethylbenzoyl, diphenylphosphine oxide or benzoin diethyl ether; the cationic photoinitiator includes at least one of diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron arene salt, sulfonyloxy ketone or triaryl siloxane ether; 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.

[0084] In the embodiment of the present application, the photoinitiator is preferably benzil dimethyl ketal, that is, photoinitiator 651, whose chemical formula is:

[0085]

[0086] In the present application, the spacer particles are preferably polystyrene microspheres.

[0087] In a second aspect, the present application provides a method for preparing the above-mentioned liquid crystal film with intelligent information encryption function, comprising:

[0088] S1, mixing the raw materials uniformly, adding them between the substrates until the space between the substrates is filled, and performing a first curing by ultraviolet light irradiation polymerization or / and thermal polymerization to obtain a film A;

[0089] Specifically, under the action of ultraviolet light irradiation and photoinitiator, the flexible photopolymer monomer is polymerized and cured by ultraviolet light to form a honeycomb polymer substrate, and the liquid crystal is filled in the holes of the polymer substrate; a small amount of rod-shaped photopolymer monomer is polymerized and cured, and most of it is distributed in the liquid crystal. This is because the collision probability between the free radicals of the flexible polymer monomer is much greater than the collision probability between the free radicals of the rigid rod-shaped photopolymer monomer. Therefore, during the first photocuring, it is mainly the flexible photopolymer monomer that is cured within a certain period of time.

[0090] When the flexible polymerizable monomer is a flexible thermal polymerizable monomer, under heating conditions, the flexible thermal polymerizable monomer is cured by thermal polymerization to form a honeycomb-shaped polymer substrate, and the liquid crystal is filled in the pores of the polymer substrate; the rod-shaped photopolymerizable monomer is not polymerized and cured, and is distributed in the liquid crystal.

[0091] When the flexible polymerizable monomer is a flexible photopolymerizable monomer, the temperature of ultraviolet light irradiation polymerization is -20 to 60°C, the time is 5 to 90 seconds, and the ultraviolet light intensity is 0.5 to 300 mW / cm 2 When the flexible polymerizable monomer is a flexible thermal polymerizable monomer, the thermal polymerization temperature is 20 to 120° C. and the time is 0.1 to 1 h.

[0092] When the flexible polymerizable monomer is a blend of a flexible photopolymerizable monomer and a flexible thermal polymerizable monomer, the curing of the flexible polymerizable monomer can be carried out in steps of ultraviolet light irradiation polymerization and thermal polymerization.

[0093] S2, aligning or not aligning the liquid crystal molecules in the film A, irradiating the film A with ultraviolet light through a mask for a time t1 at a temperature T1, and performing a second curing to obtain a film B;

[0094] Specifically, by applying an electric field to the film A to control the orientation of the liquid crystal molecules, the rod-shaped photopolymerizable monomers can be oriented along the direction of the electric field with the liquid crystal molecules or oriented together with the liquid crystal molecules as the temperature changes. When the film A needs to be oriented, at a temperature T1, a mask is covered on the film A, and an electric field is applied at the same time to make the rod-shaped photopolymerizable monomers and liquid crystal molecules in the film A form a certain orientation. Ultraviolet light is irradiated through the mask to make the photopolymerizable monomers in the light-transmitting area of ​​the mask undergo a polymerization reaction, completing the second curing. The mask of the present application, the actual material is as follows Figure 1 shown.

[0095] During the second curing, T1 is -20 to 60°C. According to the specific requirements of the customized pattern, t1 is 1 to 600s, and the UV intensity is 0.5 to 300mW / cm 2 .

[0096] S3, applying an electric field to the film B for orientation, or not orientation, irradiating the film B with ultraviolet light for t2 time at temperature T2, performing a third curing, and obtaining a liquid crystal film with intelligent information encryption function.

[0097] By applying an electric field to film B to control the molecular orientation, the rod-shaped photopolymerizable monomers can be oriented along the direction of the electric field with the liquid crystal molecules or oriented together with the liquid crystal molecules as the temperature changes. When film B needs to be oriented, at temperature T2, an electric field is applied to film B to make the unpolymerized rod-shaped photopolymerizable monomers and liquid crystal molecules form a certain orientation, and ultraviolet light is used to irradiate film B, so that the rod-shaped photopolymerizable monomers in the mask-shielded area during the second curing process undergo polymerization reaction, completing the third curing. Among them, T2 is -20 to 60°C; according to the specific requirements of the customized pattern, t2 is 5 to 300s, and the ultraviolet light intensity is 0.5 to 300mW / cm 2 .

[0098] Since the content of the remaining rod-shaped photopolymerizable monomers in the area not blocked by the mask and the area blocked by the mask is different after the second photocuring, the polymer network density in the area not blocked by the mask and the area blocked by the mask is different during the second curing process after the third photocuring. The present application prepares a polymer network with a certain orientation and different fiber density in the light-transmitting area and the blocked area of ​​the liquid crystal film not blocked by the mask through the second curing and the third curing.

[0099] When the present application uses a liquid crystal material with a specific phase change, in addition to using the above-mentioned preparation method to prepare the target film, it is also possible not to apply an electric field, and by adjusting the temperature T1 of the second curing and the temperature T2 of the third curing, the molecular orientation of the liquid crystal and photopolymerization monomer mixture of the rod-shaped photopolymerization monomer during the second and third photocuring processes can be controlled, thereby controlling the orientation of the formed polymer network fiber. At the same time, the difference in diffusion speed of the rod-shaped photopolymerization monomer free radicals at high and low temperatures and in different phases, combined with the use of a mask, enables the polymer network fibers in different regions to have different densities.

[0100] In the liquid crystal film of the present application, the polymer network orientations in regions with different polymer network fiber densities may be the same or different.

[0101] In the present application, when the flexible photopolymerizable monomer is a flexible photopolymerizable monomer, since the free radical collision probability of the flexible photopolymerizable monomer is greater than the free radical collision probability of the rod-shaped photopolymerizable monomer, when the two coexist, the polymerization rate of the flexible photopolymerizable monomer is greater than the polymerization rate of the rod-shaped photopolymerizable monomer, so the steps S1 and S2 in the above preparation method can be combined into one step; it can also be prepared by the following method:

[0102] The raw materials are mixed evenly to form a precursor solution, and the precursor solution is added between the substrates until the space between the substrates is filled. Under the condition that the liquid crystal material molecules in the precursor solution are oriented or not oriented, ultraviolet light is irradiated to the precursor solution through a photomask for t1 time at a temperature T1 to perform the first curing to obtain a film A;

[0103] Under the condition that the liquid crystal material molecules in the film A are oriented or not oriented, the film A is irradiated with ultraviolet light for t2 time at temperature T2 for a second curing to obtain a liquid crystal film with intelligent information encryption function.

[0104] In this case, T1 is -20~60℃, T2 is -20~60℃, t1 is 1~600s, t2 is 5~300s, and the UV intensity is 0.5~300mW / cm 2 .

[0105] The preparation process and working principle of the liquid crystal film of the present application are shown in FIG2. When the liquid crystal used is a positive cholesteric liquid crystal, the liquid crystal film is a liquid crystal film with an electrically controlled reversible information patterning function, and its preparation process and working principle are shown in FIG2. Figure 2a When no electric field is applied, in the area with low density of polymer network fibers, the anchoring effect of polymer network on liquid crystal pairs is relatively small, the liquid crystal molecules form a random orientation, and the liquid crystal film is in a scattered state; in the area with high density of polymer network fibers, the anchoring effect of polymer network on liquid crystal molecules is large, the liquid crystal molecules are vertically oriented, and the liquid crystal film is transparent; at this time, a light scattering pattern is displayed on the transparent background, as shown in FIG. Figure 3 By controlling the size of the mask, a transparent pattern can also be displayed on a light-scattering background, such as Figure 4 As shown in Figure 1. When an electric field is applied, the liquid crystal is vertically oriented, the liquid crystal film as a whole becomes transparent, and the pattern disappears. When the electric field is turned off, the pattern reappears.

[0106] 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 a temperature-controlled reversible information patterning function, and its preparation process and working principle are as follows Figure 2b As shown. When the ambient temperature is lower than the phase transition temperature of the liquid crystal, the smectic A liquid crystal molecules are vertically oriented, and the film is transparent as a whole. When the ambient temperature is higher than the phase transition temperature of the liquid crystal, in the area where the polymer network fiber density of the liquid crystal film is relatively small, the anchoring effect of the polymer network on the liquid crystal is relatively small, the liquid crystal undergoes a phase transition, and the film switches to a scattering state; while in the area where the polymer network fiber density of the liquid crystal film is relatively large, the anchoring effect of the polymer network on the liquid crystal molecules is relatively large, and when the liquid crystal is heated to the cholesteric phase, the liquid crystal molecules are still vertically oriented, and the film is still transparent; at this time, a pre-set light scattering pattern appears on the transparent background, as shown in FIG. Figure 5 By controlling the size of the mask, a transparent pattern can also be displayed on a light-scattering background. Figure 6 When the ambient temperature is lower than the transition temperature, the film as a whole becomes transparent and the pattern disappears.

[0107] The liquid crystal film of the present application has an intelligent information encryption function and can be used in information patterning controllable devices. The liquid crystal film displays (or does not display) an information pattern before applying an electric field, disappears (or displays) the information pattern after applying the electric field, and displays (or does not display) the information pattern again after turning off the electric field; or, the liquid crystal film has no (or has) an information pattern when it is lower than the phase transition temperature of the liquid crystal, and presents (or does not present) an information pattern when it is higher than the phase transition temperature of the liquid crystal, and disappears (or displays) the information pattern again when the ambient temperature is lower than the phase transition temperature of the liquid crystal. By designing the shape and size of the mask to prepare regions of different shapes and sizes with different light transmittances, the customization of specific information patterns can be achieved on the liquid crystal film, which has broad application prospects in the fields of consumer electronics and information encryption.

[0108] The present application is further described below by way of examples.

[0109] Example 1

[0110] This embodiment provides a method for preparing a liquid crystal film with an electrically controlled reversible information patterning function, and its raw materials and proportions are shown in Table 1:

[0111] Table 1 Raw material ratio of Example 1

[0112]

[0113]

[0114] S1, mix the raw materials described in Table 1 evenly, sandwich them between two layers of ITO conductive plastic film, and use a light intensity of 10mW / cm at 15℃. 2 The film is irradiated with ultraviolet light for 20 seconds to initiate polymerization of most of the flexible photopolymerizable monomers, thereby obtaining a film A having a honeycomb polymer matrix;

[0115] S2, place the customized mask on film A, apply an electric field to film A to turn the film into a transparent state, heat film A to 40°C, and use a light intensity of 15mW / cm 2 Film A was irradiated with ultraviolet light for 600s, and a region with a relatively high density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film B;

[0116] S3, remove the mask and continue to apply the electric field to keep the film B transparent. 2 The film is irradiated with ultraviolet light for 180 seconds to form regions with relatively low polymer network fiber density outside the regions with relatively high polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0117] The mask used in Example 1 is Figure 1The mask on the right shows the actual image of the liquid crystal film with intelligent information encryption function. Figure 3 When no electric field is applied, the Huawei logo with light scattering appears on a transparent background. After the electric field is applied, the film as a whole becomes transparent and the information pattern disappears.

[0118] Example 2

[0119] This embodiment provides a method for preparing a liquid crystal film with an electrically controlled reversible information patterning function, and its raw materials and proportions are shown in Table 1:

[0120] S1, mix the raw materials described in Table 1 evenly, sandwich them between two layers of ITO conductive plastic film, and use a light intensity of 10mW / cm at 15℃. 2 The film is irradiated with ultraviolet light for 20 seconds to initiate polymerization of most of the flexible photopolymerizable monomers, thereby obtaining a film A having a honeycomb polymer matrix;

[0121] S2, place the customized mask on film A, apply an electric field to film A to turn the film into a transparent state, heat film A to 40°C, and use a light intensity of 15mW / cm 2 Film A was irradiated with ultraviolet light for 600s, and a region with a relatively high density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film B;

[0122] S3, remove the mask and continue to apply the electric field to keep the film B transparent. 2 The film is irradiated with ultraviolet light for 180 seconds to form regions with relatively low polymer network fiber density outside the regions with relatively high polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0123] The mask used in Example 2 is Figure 1 The mask on the left shows the actual picture of the liquid crystal film with intelligent information encryption function. Figure 4 When no electric field is applied, a transparent Huawei logo appears against a light-scattering background. After an electric field is applied, the film as a whole becomes transparent and the information pattern disappears.

[0124] Example 3

[0125] This embodiment provides a method for preparing a liquid crystal film with an electrically controlled reversible information patterning function, and its raw materials and proportions are shown in Table 1:

[0126] S1, mix the raw materials described in Table 1 evenly, sandwich them between two layers of ITO conductive plastic film, and use a light intensity of 10mW / cm at 15℃. 2 The film is irradiated with ultraviolet light for 20 seconds to initiate polymerization of most of the flexible photopolymerizable monomers, thereby obtaining a film A having a honeycomb polymer matrix;

[0127] S2, place the customized mask on film A, apply an electric field to film A to turn the film into a transparent state, heat film A to 15°C, and use a light intensity of 5mW / cm 2 Film A was irradiated with ultraviolet light for 180 seconds, and a region with a relatively low density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film B;

[0128] S3, remove the mask and continue to apply the electric field to keep the film B transparent. 2 The film is irradiated with ultraviolet light for 600 seconds to form areas with a relatively high polymer network fiber density outside the areas with a relatively low polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0129] The mask used in Example 3 is Figure 1 The mask on the right shows the actual image of the liquid crystal film with intelligent information encryption function. Figure 4 When no electric field is applied, a transparent Huawei logo appears against a light-scattering background. After an electric field is applied, the film as a whole becomes transparent and the information pattern disappears.

[0130] Example 4

[0131] This embodiment provides a method for preparing a liquid crystal film with a temperature-controlled reversible patterning function, and its raw materials and proportions are shown in Table 2:

[0132] Table 2 Raw material ratio of Example 3

[0133]

[0134] Among them, the composition of the smectic-cholesteric phase transition liquid crystal (SmA-ChLC) is as follows:

[0135]

[0136] S1, mix the raw materials described in Table 1 evenly, sandwich them between two layers of ITO conductive plastic film, and use a light intensity of 10mW / cm at 15℃. 2 The film is irradiated with ultraviolet light for 20 seconds to initiate polymerization of most of the flexible photopolymerizable monomers, thereby obtaining a film A having a honeycomb polymer matrix;

[0137] S2, place the customized mask on film A, apply an electric field to film A to turn the film into a transparent state, heat film A to 40°C, and use a light intensity of 15mW / cm 2 Film A was irradiated with ultraviolet light for 600s, and a region with a relatively high density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film B;

[0138] S3, remove the mask and continue to apply the electric field to keep the film B transparent. 2 The film is irradiated with ultraviolet light for 180 seconds to form regions with relatively low polymer network fiber density outside the regions with relatively high polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0139] The mask used in Example 4 is Figure 1 The mask on the right shows the actual image of the liquid crystal film with intelligent information encryption function. Figure 5 At low temperatures, the liquid crystal film is transparent, and at high temperatures, the Huawei logo pattern is displayed in a light-scattering state against a transparent background.

[0140] Example 5

[0141] This embodiment provides a method for preparing a liquid crystal film with a temperature-controlled reversible patterning function, and its raw materials and proportions are shown in Table 2:

[0142] S1, mix the raw materials described in Table 1 evenly, sandwich them between two layers of ITO conductive plastic film, and use a light intensity of 10mW / cm at 15℃. 2 The film is irradiated with ultraviolet light for 20 seconds to initiate polymerization of most of the flexible photopolymerizable monomers, thereby obtaining a film A having a honeycomb polymer matrix;

[0143] S2, place the customized mask on film A, apply an electric field to film A to turn the film into a transparent state, heat film A to 40°C, and use a light intensity of 15mW / cm 2 Film A was irradiated with ultraviolet light for 600s, and a region with a relatively high density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film B;

[0144] S3, remove the mask and continue to apply the electric field to keep the film B transparent. 2 The film is irradiated with ultraviolet light for 180 seconds to form regions with relatively low polymer network fiber density outside the regions with relatively high polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0145] The mask used in Example 5 is Figure 1 The mask on the left shows the actual picture of the liquid crystal film with intelligent information encryption function. Figure 6 At low temperatures, the liquid crystal film is transparent, and at high temperatures, a transparent Huawei logo pattern is displayed against a light-scattering background.

[0146] Example 6

[0147] This embodiment provides a two-step method for preparing a liquid crystal film with a temperature-controlled reversible patterning function, and its raw materials and proportions are shown in Table 1:

[0148] S1, the raw materials described in Table 1 are mixed evenly and sandwiched between two layers of ITO conductive plastic films; an electric field is applied to the films, and a customized mask is placed on the ITO conductive plastic films, and a light intensity of 20 mW / cm is used at 50°C. 2 The film was irradiated with ultraviolet light for 600s, and a region with a relatively high density of polymer network fibers was formed in the light transmission region of the mask, thereby obtaining film A;

[0149] S2, remove the mask and continue to apply the electric field to keep the film A transparent. 2 The film is irradiated with ultraviolet light for 180 seconds to form regions with relatively low polymer network fiber density outside the regions with relatively high polymer network fiber density, thereby obtaining a liquid crystal film with intelligent information encryption function.

[0150] The mask used in Example 6 is Figure 1 The mask on the right shows the actual image of the liquid crystal film with intelligent information encryption function. Figure 7 When no electric field is applied, the Huawei logo with light scattering appears on a transparent background. After the electric field is applied, the film as a whole becomes transparent and the information pattern disappears.

[0151] Although the present application has been described in detail in general terms and in specific embodiments in this specification, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in the present application.

Claims

1. A liquid crystal film with intelligent information encryption function, characterized in that: The invention comprises two transparent substrates 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 the pores of the polymer matrix, wherein the liquid crystals have 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 can have a reversible information pattern that disappears (or appears) when an electric field is applied and appears (or disappears) after the electric field is removed; Or a reversible information pattern that disappears (or appears) at low temperatures and appears (or disappears) at high temperatures.

2. The liquid crystal film with intelligent information encryption function according to claim 1, characterized in that: The raw materials of the composite functional layer include 5 to 60 wt % of flexible polymerizable monomers, 0.5wt% to 15wt% of rod-shaped photopolymerizable monomer, 20wt% to 94.4wt% of liquid crystal, 0.1wt% to 5wt% of initiator, and 0.1 to 2wt% of spacer particles based on the sum of the amounts of flexible polymerizable monomer, rod-shaped photopolymerizable monomer, liquid crystal mixture and initiator.

3. The liquid crystal film with intelligent information encryption function according to claim 2, characterized in that: The flexible polymerizable monomer includes at least one of a flexible photopolymerizable monomer or a flexible thermal polymerizable monomer; wherein the flexible photopolymerizable monomer can be subjected to free radical polymerization or cationic polymerization under ultraviolet light irradiation; and the flexible thermal polymerizable monomer can be subjected to thermal polymerization under heating conditions; The rod-shaped photopolymerizable monomer can undergo free radical polymerization or cationic polymerization under ultraviolet light irradiation; The liquid crystal is a positive liquid crystal, a negative liquid crystal or a dual-frequency driven liquid crystal; The initiator is a free radical initiator, a cationic photoinitiator or a thermal initiator; The spacer particles are styrene or silicon dioxide microspheres, and the diameter thereof is 2 micrometers to 100 micrometers.

4. The liquid crystal film with intelligent information encryption function according to claim 3, characterized in that: The flexible photopolymerizable monomer includes at least one of an acrylate monomer, an olefin monomer, a vinyl ether monomer or an epoxy monomer; The flexible thermal polymerizable monomer includes 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, negative liquid crystal and dual-frequency driven liquid crystal all include 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; Wherein, the cholesteric liquid crystal is prepared by cholesterol compounds, liquid crystal containing cholesterol compounds or nematic liquid crystal and chiral compounds; the liquid crystal with smectic A phase-cholesteric phase transition is prepared by cholesterol compounds, liquid crystal containing cholesterol compounds, or liquid crystal with smectic A phase-nematic phase transition and chiral compounds; the chiral molecule is S811, R811, S1011, R1011 or CB15; The initiator includes at least one of benzoin ethyl ether, benzophenone, thioanthrone, benzil dimethyl ketal, 2-hydroxy-2-methyl-1-phenylacetone, trimethylbenzoyl diphenyl phosphine oxide, benzoin diethyl ether diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron arene salt, sulfonyloxy ketone, triaryl siloxy 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 3, characterized in that: The rod-shaped photopolymerizable monomer has a structure shown in any one of formulas (1) to (8) or a combination thereof: Wherein, m is 1 to 20; n is 1 to 20; x is 1 to 2; y is 1 to 2; E and Q are acrylate, epoxy, vinyl ether or olefin functional groups.

6. The liquid crystal film with intelligent information encryption function according to claim 2, characterized in that: The raw materials of the composite functional layer also include dyes; The dye is an azo dye, anthraquinone dye or phthalocyanine dye.

7. The method for preparing a liquid crystal film with intelligent information encryption function according to any one of claims 2 to 6, characterized in that: include: S1, mixing the raw materials uniformly, adding them between the substrates until the space between the substrates is filled, and performing a first curing by ultraviolet light irradiation polymerization or / and thermal polymerization to obtain a film A; S2, under the condition that the liquid crystal material molecules in the film A are oriented or not oriented, ultraviolet light is irradiated to the film A through a photomask at a temperature T1 for a time t1, and a second curing is performed to obtain a film B; S3, under the condition that the liquid crystal material molecules in the film B are oriented or not oriented, the film B is irradiated with ultraviolet light for t2 time at temperature T2, and a third curing is performed to obtain 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: The raw materials are mixed evenly to form a precursor solution, and the precursor solution is added between the substrates until the space between the substrates is filled. Under the condition that the liquid crystal material molecules in the precursor solution are oriented or not oriented, ultraviolet light is irradiated to the precursor solution through a photomask for t1 time at a temperature T1 to perform the first curing to obtain a film A; Under the condition that the liquid crystal material molecules in the film A are oriented or not oriented, the film A is irradiated with ultraviolet light for t2 time at temperature T2 for a second curing to obtain a liquid crystal film with intelligent information encryption function.

9. The preparation method according to claim 7 or 8, characterized in that: The orientation is specifically: controlling 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 to 60°C, the time is 5 to 90 seconds, and the ultraviolet light intensity is 0.5 to 300 mW / cm 2 When the flexible polymerizable monomer is a flexible thermal polymerizable monomer, thermal polymerization is adopted, and the temperature is 20 to 120° C. and the time is 0.1 to 1 hour; 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 polymerized by ultraviolet radiation and thermal polymerization in steps; and / or, T1 is -20~60℃; t1 is 1~600s, UV intensity is 0.5~300mW / cm 2 ; and / or, T2 is -20~60℃, t2 is 5~300s, and UV intensity is 0.5~300mW / cm 2 .

10. Use of the liquid crystal film with intelligent information encryption function described in any one of claims 1 to 6 or the liquid crystal film with intelligent information encryption function prepared by the preparation method described in any one of claims 7 to 9 in a patterned controllable device.

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