A humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation and a preparation method and application thereof

Abstract

This invention relates to the field of liquid crystal materials technology, and discloses a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, its preparation method, and its application. The preparation method includes: blending a liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, a carboxyl-containing polymerizable monomer, a carboxyl-containing non-polymerizable monomer, a liquid crystal chiral agent, and a photoinitiator to obtain a liquid crystal mixture; filling the mixture into a liquid crystal cell, then polymerizing it under ultraviolet light; immersing the resulting self-supporting film in a potassium hydroxide aqueous solution to convert the carboxyl groups into hygroscopic potassium salts, thus obtaining the target liquid crystal film. This invention, by irradiating the liquid crystal film with ultraviolet light, can induce orthogonal [4+4] cycloaddition reactions of anthracene groups in the polymer network. By controlling the ultraviolet exposure, preset information can be pre-encoded as a spatially heterogeneous crosslinking density distribution within the film, achieving dynamic display and concealment of colorful patterns across the entire spectrum under ambient humidity.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal materials technology, specifically to a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, its preparation method, and its application. Background Technology

[0002] Smart materials with dynamic response properties have attracted widespread attention from academia and industry in recent years. Especially in fields such as biomimetic optics and anti-counterfeiting detection, developing material systems capable of sensing external stimuli and providing precise physical or chemical feedback has become a core research focus. Cholesteric liquid crystals and photoresponsive polymers, due to their unique selective light reflection, are considered ideal platforms for constructing next-generation adaptive photonic devices. Stimulus-responsive cholesteric liquid crystals can influence reflected color by controlling the pitch through stimuli such as light, electricity, heat, and chemicals. Humidity-responsive cholesteric liquid crystal films, by controlling structural color through the swelling of the polymer network by water, and given that water is readily available in nature and harmless, humidity-responsive cholesteric liquid crystal films have garnered significant attention.

[0003] In existing technologies, most humidity-responsive cholesteric liquid crystal films exhibit globally uniform dynamic response behavior after film formation, manifesting as monotonous and untunable color changes. This uniform distribution of physical properties makes it difficult for the material to present spatially differentiated color distributions on the same horizontal plane under a single stimulus, limiting its application in complex information storage and high-precision image display. Although commonly used techniques such as local chemical modification or mask lithography can be used to construct optical patterns, these methods often suffer from drawbacks such as easily disrupting the ordered orientation of liquid crystal molecules, cumbersome processing procedures, or limited pattern resolution due to component diffusion.

[0004] As research into the applications of liquid crystal films continues to deepen, developing cholesteric liquid crystal films capable of high-resolution patterning is essential to meet application requirements. Furthermore, there are currently no publicly available reports on achieving humidity-responsive cholesteric liquid crystal film patterning through controlled programming of the polymer's internal network using ultraviolet light. Summary of the Invention

[0005] This invention discloses a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, its preparation method and application, aiming to solve the technical problem that existing humidity-responsive cholesteric liquid crystal films cannot achieve high-precision multicolor pattern programming.

[0006] To achieve the above objectives, on the one hand, the present invention provides a method for preparing a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, characterized by comprising the following steps:

[0007] S1. The liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, carboxyl-containing non-polymerizable monomer, liquid crystal chiral agent and photoinitiator are mixed evenly to obtain a liquid crystal mixture.

[0008] S2. After the liquid crystal mixture is poured into a liquid crystal cell, a self-polymerization reaction is carried out under ultraviolet light irradiation. The self-supporting film obtained after polymerization is immersed in an aqueous potassium hydroxide solution to convert the carboxyl groups into hygroscopic potassium salts, thereby obtaining a humidity-responsive cholesteric phase liquid crystal film based on the photodimerization regulation of anthracene functional groups; wherein:

[0009] The liquid crystal polymerizable monomer includes one or more of the following: a first polymerizable monomer, a second polymerizable monomer, a third polymerizable monomer, and a fourth polymerizable monomer.

[0010] The first polymeric monomer possesses the chemical structure shown in formula (I):

[0011]

[0012] Formula (I)

[0013] Among them, R1 and R2 are selected independently from each other. , , , and One of them; X is one of -CH3, -Cl and -F; n is any integer from 1 to 18;

[0014] The second polymeric monomer possesses the chemical structure shown in formula (II):

[0015]

[0016] Equation (II)

[0017] Where R1 is , , , and One of them; R2 is -CN, -F, and -OC. m H 2m+1 One of them, where m is any integer from 1 to 18; n is any integer from 1 to 18;

[0018] The third polymeric monomer possesses the chemical structure shown in formula (III):

[0019]

[0020] Equation (III)

[0021] Where R is , , , and One of them; n is any integer from 1 to 18;

[0022] The fourth polymeric monomer possesses the chemical structure shown in formula (IV):

[0023]

[0024] Formula (IV)

[0025] Among them, R1 and R2 are selected independently from each other. , , , and One of them; m is any integer from 1 to 3; n is any integer from 1 to 18;

[0026] The anthracene-containing polymerizable monomer includes one or more of the fifth polymerizable monomer, the sixth polymerizable monomer, the seventh polymerizable monomer, and the eighth polymerizable monomer;

[0027] The fifth polymeric monomer possesses the chemical structure shown in formula (V):

[0028]

[0029] Formula (V)

[0030] Among them, R1 and R2 are selected independently from each other. , , , and One of them;

[0031] The sixth polymeric monomer possesses the chemical structure shown in formula (VI):

[0032]

[0033] Formula (VI)

[0034] Where R1 is , , , and One of them; R2 is -CN, -F, and -OC. m H 2m+1 One of them;

[0035] The seventh polymeric monomer possesses the chemical structure shown in formula (VII):

[0036]

[0037] Formula (VII)

[0038] Where R is , , , and One of them;

[0039] The eighth polymeric monomer possesses the chemical structure shown in formula (VIII):

[0040]

[0041] Formula (VIII)

[0042] Among them, R1 and R2 are selected independently from each other. , , , , and One of them;

[0043] The carboxyl-containing polymerizable monomer includes one or more of the ninth polymerizable monomer, the tenth polymerizable monomer, and the eleventh polymerizable monomer;

[0044] The ninth polymeric monomer possesses the chemical structure shown in formula (IX):

[0045]

[0046] Formula (IX)

[0047] Wherein, R1 is selected from , , , and One of them, R2 is Or, R1 is R2 is selected from , , , and One of them; X is one of -CH3, -Cl and -F; n is any integer from 1 to 18;

[0048] The tenth polymeric monomer possesses the chemical structure shown in formula (X):

[0049]

[0050] Formula (X)

[0051] Wherein, R1 is selected from , , , and One of them, R2 is Or, R1 is R2 is selected from , , , and One of them; n is any integer from 1 to 18;

[0052] The eleventh polymeric monomer possesses the chemical structure shown in formula (XI):

[0053]

[0054] Formula (XI)

[0055] Wherein, R1 is selected from , , , and One of them, R2 is Or, R1 is R2 is selected from , , , and One of them; n is any integer from 1 to 18;

[0056] The non-polymerizable monomer containing a carboxyl group possesses the chemical structure shown in formula (IX):

[0057]

[0058] Formula (IX)

[0059] Where R is selected from , and One of them; n is any integer from 1 to 18.

[0060] As a further preferred technical solution of the present invention, by weight, there are 10-35 parts of liquid crystal polymerizable monomer, 3-20 parts of anthracene-containing polymerizable monomer, 20-70 parts of carboxyl-containing polymerizable monomer, 10-40 parts of carboxyl-containing non-polymerizable monomer, 1-10 parts of liquid crystal chiral agent, and 0.5-3 parts of photoinitiator.

[0061] As a further preferred technical solution of the present invention, the liquid crystal mixture may be incorporated with one or more thiol monomers selected from dithiols and polythiols, and the ratio of the total molar amount of polymerizable groups in the liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, and liquid crystal chiral agent to the total molar amount of mercapto groups in the thiol monomer is 1:(0-0.6).

[0062] As a further preferred embodiment of the present invention, the dithiol is ethylenedithiol, di(mercaptoacetic acid)-1,4-butanediol, 2,2'-(1,2-ethylenedioxy)bis(ethanediol) or ethylene glycol dimercaptoacetate; and / or, the polythiol is pentaerythritol tetra-3-mercaptopropionate or trimethylolpropane tris(3-mercaptopropionate).

[0063] As a further preferred embodiment of the present invention, the photoinitiator is one or more of 2-hydroxy-methylphenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-difluoro-3-pyrrolophenyldicyclopentadiene), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0064] As a further preferred embodiment of the present invention, the amount of the photoinitiator is 0.1-2% of the total mass of the liquid crystal polymerizable monomer and the anthracene-containing polymerizable monomer.

[0065] As a further preferred embodiment of the present invention, the wavelength of the ultraviolet light is 320~400 nm.

[0066] According to a second aspect of the present invention, the present invention also provides a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, which is prepared by the above-described preparation method.

[0067] According to a third aspect of the present invention, the present invention also provides an application of a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation in humidity-responsive pattern display.

[0068] As a further preferred technical solution of the present invention, the humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups is patterned by controlling the amount of ultraviolet light irradiation, causing anthracene to undergo different degrees of dimerization, realizing programmable swelling of the polymer network, and thus obtaining a humidity-responsive liquid crystal film with a hidden pattern, which can display different colors under different relative humidity. The humidity-responsive liquid crystal film with a hidden pattern can be used as an anti-counterfeiting label, information storage, and pattern display under different humidity conditions. When used as an anti-counterfeiting label, its pattern is a pattern with coded information, such as a QR code or barcode.

[0069] In the composition of the humidity-responsive cholesteric liquid crystal film of this invention, liquid crystal polymerizable monomers form the network framework. Chiral dopants induce the self-assembly of liquid crystal molecules to form a periodic helical nanostructure, thereby obtaining structural colors based on selective Bragg reflection. To impart humidity responsiveness to the system, polymerizable and non-polymerizable monomers containing carboxyl groups are introduced. These components form numerous intermolecular hydrogen bonds between the polymer network. After alkali treatment, the hydrogen bonds in the network break and transform into highly hygroscopic carboxylates, allowing the polymer network to dynamically swell or shrink with changes in humidity, thus affecting the pitch and ultimately achieving reversible control of the structural color. The carboxyl-containing non-polymerizable monomers dissolve in the alkali solution after being treated with the highly hygroscopic carboxylates and are washed out of the film, giving the polymer network of the film a stronger swelling capacity and resulting in a greater redshift under humid conditions.

[0070] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0071] The preparation method provided by this invention involves polymerizing a liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, carboxyl-containing non-polymerizable monomer, and a liquid crystal chiral agent at 355 nm under the action of an initiator. The resulting self-supporting film is then immersed in a potassium hydroxide aqueous solution, causing all carboxyl groups to be converted into hygroscopic potassium salts, thus obtaining a humidity-responsive cholesteric phase liquid crystal film based on the photodimerization regulation of anthracene functional groups. By irradiating the liquid crystal film with ultraviolet light, orthogonal [4+4] cycloaddition reactions can be induced in the anthracene groups within the polymer network. By controlling the ultraviolet exposure, preset information can be pre-encoded into a spatially heterogeneous crosslinking density distribution within the film, enabling the dynamic display and concealment of multi-colored patterns across the entire spectrum under ambient humidity. Attached Figure Description

[0072] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0073] Figure 1 This is a schematic diagram illustrating the mechanism by which the swelling capacity of the cholesteric liquid crystal film network in response to humidity is programmed through the [4+4] cycloaddition reaction of anthracene in Example 1.

[0074] Figure 2 This is a diagram of the bond exchange mechanism within the liquid crystal film where anthracene photodimerization is achieved through optical programming in Example 1.

[0075] Figure 3 This is a schematic diagram showing the changes in the reflection wavelength of the cholesteric phase liquid crystal film with different degrees of anthracene dimerization in Example 1.

[0076] Figure 4 This is a schematic diagram illustrating the process of programming a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups using ultraviolet laser in Example 1, as well as the display and disappearance of the pattern.

[0077] Figure 5 The image shows a physical model of the humidity-responsive cholesteric liquid crystal film CLCN1, prepared in Example 1, with a pattern written by laser under high humidity conditions.

[0078] Figure 6 The image shows a physical model of the humidity-responsive cholesteric liquid crystal film CLCN2, prepared in Example 2, with a pattern written by laser under high humidity conditions.

[0079] Figure 7 The image shows a physical model of the humidity-responsive cholesteric liquid crystal film CLCN3, prepared in Example 3, with a pattern written by laser under high humidity conditions.

[0080] Figure 8 The image shows a physical model of the humidity-responsive cholesteric liquid crystal film CLCN4, prepared in Example 4, with a pattern written by laser under high humidity conditions.

[0081] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0082] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0083] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0084] Example 1

[0085] This embodiment provides a method for preparing a humidity-responsive cholesteric liquid crystal film CLCN1 based on the photodimerization regulation of anthracene functional groups, comprising the following steps:

[0086] S101: The liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, carboxyl-containing non-polymerizable monomer, liquid crystal chiral agent and photoinitiator are blended in the proportions shown in Table 1 to obtain a mixture;

[0087] S102: On a hot stage at 50 °C, the resulting mixture was poured into a liquid crystal cell prepared with a 30 μm gap pad, and then 20 mW / cm² was used. 2Irradiated with 450 nm light for 120 min to obtain a humidity-responsive cholesteric liquid crystal film CLCN1 based on the photodimerization regulation of anthracene functional groups.

[0088] Table 1 Sample formulations for preparing CLCN1

[0089]

[0090] Example 2

[0091] This embodiment provides a method for preparing a humidity-responsive cholesteric liquid crystal film CLCN2 based on the photodimerization regulation of anthracene functional groups, comprising the following steps:

[0092] S201: The liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, carboxyl-containing nonpolymerizable monomer, liquid crystal chiral agent, polythiol and photoinitiator are blended in the proportions shown in Table 2 to obtain a mixture;

[0093] S202: On a hot stage at 50 °C, the resulting mixture was poured into a liquid crystal cell prepared with a 50 μm gap pad; using 30 mW / cm 2 Irradiated with 450 nm light for 90 min to obtain a humidity-responsive cholesteric liquid crystal film CLCN2 based on the photodimerization regulation of anthracene functional groups.

[0094] Table 2 Sample formulations for preparing CLCN2

[0095]

[0096] Example 3

[0097] This embodiment provides a method for preparing a humidity-responsive cholesteric liquid crystal film CLCN3 based on the photodimerization regulation of anthracene functional groups, comprising the following steps:

[0098] S301: A mixture is obtained by blending liquid crystal polymerizable monomers, anthracene-containing polymerizable monomers, carboxyl-containing polymerizable monomers, carboxyl-containing nonpolymerizable monomers, liquid crystal chiral agents, dithiols, and photoinitiators in the proportions shown in Table 3.

[0099] S302: On a hot stage at 55 °C, the resulting mixture was poured into a liquid crystal cell prepared with a 20 μm gap pad; using 40 mW / cm 2 Irradiated with 450 nm light for 75 min to obtain a humidity-responsive cholesteric liquid crystal film CLCN3 based on the photodimerization regulation of anthracene functional groups.

[0100] Table 3 Sample formulations for preparing CLCN3

[0101]

[0102] Example 4

[0103] This embodiment provides a method for preparing a humidity-responsive cholesteric liquid crystal film CLCN4 based on the photodimerization regulation of anthracene functional groups, comprising the following steps:

[0104] S401: A mixture is obtained by blending liquid crystal polymerizable monomers, anthracene-containing polymerizable monomers, carboxyl-containing polymerizable monomers, carboxyl-containing nonpolymerizable monomers, liquid crystal chiral agents, dithiols, and photoinitiators in the proportions shown in Table 4.

[0105] S402: On a hot stage at 55 °C, the resulting mixture was poured into a liquid crystal cell prepared with a 20 μm gap pad; using 40 mW / cm 2 Irradiated with 450 nm light for 90 min to obtain a humidity-responsive cholesteric liquid crystal film CLCN4 based on the photodimerization regulation of anthracene functional groups.

[0106] Table 4 Sample formulations for preparing CLCN4

[0107]

[0108] To illustrate the technical effects of the humidity-responsive cholesteric phase liquid crystal film prepared by the present invention based on the photodimerization regulation of anthracene functional groups, corresponding schematic diagrams are used for explanation, such as... Figures 1 to 4 As shown.

[0109] Figure 1 This is a schematic diagram illustrating the mechanism by which the swelling capacity of the cholesteric liquid crystal film network in response to humidity is programmed via the [4+4] cycloaddition reaction of anthracene in Example 1 of this application. According to... Figure 1 It is known that the swelling kinetics of the humidity-responsive hydrogen-bonded CLCN membrane can be programmed by the dimerization of anthracene within the polymer network. This response behavior is determined by the thermodynamic interaction between water permeation into the membrane and the entropic recovery of the polymer network due to its own entropy. In the low-crosslinked regions, stronger segmental mobility allows for greater network swelling, resulting in a significant increase in pitch, expanding from the initial p0 to p2, thus causing a red shift in structural color from ultraviolet to red. The laser-induced dimerization of anthracene forms more crosslinking sites, which provides greater mechanical constraint on the polymer network swelling behavior, effectively limiting the increase in pitch, expanding from p0 to p1. Therefore, these highly dimerized regions only exhibit a red shift to blue even under high humidity.

[0110] Figure 2 This is a schematic diagram of the bond exchange mechanism within the liquid crystal film where anthracene photodimerization is achieved through optical programming in an embodiment of this application. According to... Figure 2 It is known that anthracene undergoes a [4+4] cycloaddition reaction under irradiation with a 355 nm light source.

[0111] Figure 3 This is a schematic diagram showing the changes in the reflection wavelength of the cholesteric phase liquid crystal film with different degrees of anthracene dimerization in Example 1 of this application. According to... Figure 3 It is known that cholesteric liquid crystal networks exposed to different levels of ultraviolet light undergo varying degrees of dimerization. Therefore, as relative humidity increases, the structural color of liquid crystal films with higher dimerization levels gradually changes from colorless to purple, and finally to blue; the structural color of liquid crystal films with moderate dimerization levels gradually changes from colorless to blue, and finally to green; and the structural color of liquid crystal films with high dimerization levels gradually changes from colorless to green, and finally to red. Thus, by controlling the degree of dimerization of the cholesteric liquid crystal film, full-spectrum tuning of the liquid crystal film's structural color from blue to red can be achieved. Furthermore, increasing humidity causes a red shift in the structural color, while decreasing humidity causes a blue shift; these two states are humidity-controlled and completely reversible.

[0112] Figure 4 This is a schematic diagram illustrating the process of programming a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization using ultraviolet laser in Example 1 of this application, as well as the display and disappearance of patterns. According to... Figure 4 It can be seen that after patterning the liquid crystal film CLCE1 with different laser scanning speeds (v1 (400 mm / s) - v8 (4000 mm / s)) using lasers of different powers, the patterned part of the liquid crystal film CLCN1 under high humidity environment exhibits a larger central reflection wavelength when the scanning speed is faster and the laser power is lower during the programming process; conversely, the smaller the central reflection wavelength is when the scanning speed is slower and the laser power is higher during the programming process.

[0113] To verify the technical effect of this application, the humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation prepared in the above embodiments was subjected to performance testing, and the results were as follows: Figures 5 to 7 As shown.

[0114] Figure 5 This is a photograph of the humidity-responsive cholesteric liquid crystal film CLCN1, regulated by anthracene functional group photodimerization, under high humidity conditions after laser programming patterning. Based on... Figure 5 It is known that the humidity-responsive cholesteric liquid crystal film CLCN1, prepared based on the photodimerization regulation of anthracene functional groups, was used with a laser to... The dragon and phoenix pattern is input into the thin film with a power of 200 mW and a scanning speed of 2500 mm / s, and a liquid crystal film with a yellow dragon and phoenix pattern can be obtained under high humidity (relative humidity greater than 90%).

[0115] Figure 6This is a photograph of the humidity-responsive cholesteric liquid crystal film CLCN2, regulated by anthracene functional group photodimerization, under high humidity conditions after laser programming patterning. Based on... Figure 6 It is known that the humidity-responsive cholesteric liquid crystal film CLCN2, prepared based on the photodimerization regulation of anthracene functional groups, can be used with a laser to... A dragon pattern is input into the thin film at a power of 500 mW and a scanning speed of 500 mm / s. Under high humidity (relative humidity greater than 90%), a liquid crystal film with a blue dragon pattern can be obtained.

[0116] Furthermore, the carboxyl-containing polymerizable monomer in CLCN2 is replaced with the compound shown in formula (IX), wherein R1 is selected from... R2 is With n = 6 and X = -CH3, the resulting film is etched in the same manner as CLCN1, and a yellow dragon and phoenix pattern can also be obtained under high humidity (relative humidity greater than 90%).

[0117] Figure 7 This is a photograph of the humidity-responsive cholesteric liquid crystal film CLCN3, regulated by anthracene functional group photodimerization, under high humidity conditions after laser programming patterning. Based on... Figure 7 It is known that the humidity-responsive cholesteric liquid crystal film CLCN3, prepared based on the photodimerization regulation of anthracene functional groups, was used with a laser to... A green letter pattern can be obtained by inputting the thin film with a power of 300 mW and a scanning speed of 1500 mm / s under high humidity (relative humidity greater than 90%).

[0118] Figure 8 This is a photograph of the humidity-responsive cholesteric liquid crystal film CLCN3, regulated by anthracene functional group photodimerization, under high humidity conditions after laser programming patterning. Based on... Figure 8 It is known that the humidity-responsive cholesteric liquid crystal film CLCN4, prepared based on the photodimerization regulation of anthracene functional groups, was used with a laser to... A four-leaf clover pattern can be input into a thin film at a power of 300 mW and a scanning speed of 1500 mm / s under high humidity (relative humidity greater than 90%) to obtain a liquid crystal film with a green four-leaf clover pattern.

[0119] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, characterized in that, Includes the following steps: S1. The liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, carboxyl-containing non-polymerizable monomer, liquid crystal chiral agent and photoinitiator are mixed evenly to obtain a liquid crystal mixture. S2. After the liquid crystal mixture is poured into a liquid crystal cell, a self-polymerization reaction is carried out under ultraviolet light irradiation. The self-supporting film obtained after polymerization is immersed in an aqueous potassium hydroxide solution to convert the carboxyl groups into hygroscopic potassium salts, thereby obtaining a humidity-responsive cholesteric phase liquid crystal film based on the photodimerization regulation of anthracene functional groups; wherein: The liquid crystal polymerizable monomer includes one or more of the following: a first polymerizable monomer, a second polymerizable monomer, a third polymerizable monomer, and a fourth polymerizable monomer. The first polymeric monomer possesses the chemical structure shown in formula (I): ； Formula (I) Among them, R1 and R2 are selected independently from each other. , , , and One of them; X is one of -CH3, -Cl and -F; n is any integer from 1 to 18; The second polymeric monomer possesses the chemical structure shown in formula (II): ； Equation (II) Where R1 is , , , and One of them; R2 is -CN, -F, and -OC. m H 2m+1 One of them, where m is any integer from 1 to 18; n is any integer from 1 to 18; The third polymeric monomer possesses the chemical structure shown in formula (III): ； Equation (III) Where R is , , , and One of them; n is any integer from 1 to 18; The fourth polymeric monomer possesses the chemical structure shown in formula (IV): ； Formula (IV) Among them, R1 and R2 are selected independently from each other. , , , and One of them; m is any integer from 1 to 3; n is any integer from 1 to 18; The anthracene-containing polymerizable monomer includes one or more of the fifth polymerizable monomer, the sixth polymerizable monomer, the seventh polymerizable monomer, and the eighth polymerizable monomer; The fifth polymeric monomer possesses the chemical structure shown in formula (V): ； Formula (V) Among them, R1 and R2 are selected independently from each other. , , , and One of them; The sixth polymeric monomer possesses the chemical structure shown in formula (VI): ； Formula (VI) Where R1 is , , , , and One of them; R2 is -CN, -F, and -OC. m H 2m+1 One of them; The seventh polymeric monomer possesses the chemical structure shown in formula (VII): ； Formula (VII) Where R is , , , and One of them; The eighth polymeric monomer possesses the chemical structure shown in formula (VIII): ； Formula (VIII) Among them, R1 and R2 are selected independently from each other. , , , , and One of them; The carboxyl-containing polymerizable monomer includes one or more of the ninth polymerizable monomer, the tenth polymerizable monomer, and the eleventh polymerizable monomer; The ninth polymeric monomer possesses the chemical structure shown in formula (IX): ； Formula (IX) Wherein, R1 is selected from , , , and One of them, R2 is n is any integer from 1 to 18, and X is one of -CH3, -Cl, and -F; or, R1 is... R2 is selected from , , , and X is one of -CH3, -Cl and -F, and n is any integer from 1 to 18; The tenth polymeric monomer possesses the chemical structure shown in formula (X): ； Formula (X) Wherein, R1 is selected from , , , and One of them, R2 is n is any integer from 1 to 18; or, R1 is... R2 is selected from , , , and One of them, where n is any integer from 1 to 18; The eleventh polymeric monomer possesses the chemical structure shown in formula (XI): ； Formula (XI) Wherein, R1 is selected from , , , and One of them, R2 is n is any integer from 1 to 18; or, R1 is... R2 is selected from , , , and One of them, where n is any integer from 1 to 18; The non-polymerizable monomer containing a carboxyl group possesses the chemical structure shown in formula (IX): ； Formula (IX) Where R is selected from , and One of them, where n is any integer from 1 to 18.

2. The method for preparing a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation according to claim 1, characterized in that, By weight, the polymerizable monomers are: 10-35 parts liquid crystal polymerizable monomers, 3-20 parts anthracene-containing polymerizable monomers, 20-70 parts carboxyl-containing polymerizable monomers, 10-40 parts carboxyl-containing non-polymerizable monomers, 1-10 parts liquid crystal chiral agents, and 0.5-3 parts photoinitiators.

3. The method for preparing a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation according to claim 1, characterized in that, The liquid crystal mixture may incorporate one or more thiol monomers selected from dithiols and polythiols. The ratio of the total molar amount of polymerizable groups in the liquid crystal polymerizable monomer, anthracene-containing polymerizable monomer, carboxyl-containing polymerizable monomer, and liquid crystal chiral agent to the total molar amount of mercapto groups in the thiol monomer is 1:(0-0.6).

4. The method for preparing a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation according to claim 3, characterized in that, The dithiol is ethylenedithiol, di(mercaptoacetic acid)-1,4-butanediol, 2,2'-(1,2-ethylenedioxy)bis(ethanediol) or ethylene glycol dimercaptoacetate; and / or, the polythiol is pentaerythritol tetra-3-mercaptopropionate or trimethylolpropane tri(3-mercaptopropionate).

5. The method for preparing a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation according to claim 1, characterized in that, The photoinitiator is one or more of the following: 2-hydroxy-methylphenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

6. The method for preparing a humidity-responsive cholesteric phase liquid crystal film based on anthracene functional group photodimerization regulation according to claim 1, characterized in that, The amount of photoinitiator used is 0.1-2% of the total mass of the liquid crystal polymerizable monomer and the anthracene-containing polymerizable monomer.

7. The method for preparing a humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation according to claim 1, characterized in that, The wavelength of the ultraviolet light is 355 nm.

8. A humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the humidity-responsive cholesteric liquid crystal film based on anthracene functional group photodimerization regulation as described in claim 8 in humidity-responsive pattern display.

10. The application according to claim 9, characterized in that, The humidity-responsive cholesteric liquid crystal film based on the photodimerization regulation of anthracene functional groups is patterned by controlling the amount of ultraviolet light irradiation, thereby obtaining a humidity-responsive liquid crystal film with hidden patterns written on it, so as to present different colors under different relative humidity.

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