Multicolor dynamic room-temperature phosphorescent pyridinium naphthalimide doped polymer film capable of being subjected to photo-thermal programmed regulation and application

Abstract

The invention belongs to the field of multifunctional optical materials, and particularly relates to a photothermal programmed regulation and control multicolor dynamic room-temperature phosphorescent pyridinium naphthalimide doped polymer film and application of the photothermal programmed regulation and control multicolor dynamic room-temperature phosphorescent pyridinium naphthalimide doped polymer film. Different pyridine structural units (such as 4-aminopyridine, aminomethylpyridine and 3-aminopyridine) are introduced into light-responsive naphthalimide nitrogen sites, then a series of pyridinium naphthalimide derivatives (NDI-1, NDI-2 and NDI-3) are synthesized, and then the pyridinium naphthalimide derivatives are doped into a rigid polyvinyl alcohol matrix to construct the composite film. And the multifunctional polymer film with photochromism, thermochromism and room-temperature phosphorescence multi-dynamic adjustable multi-stimulus response is prepared. The method has important application potential in the fields of dynamic advanced anti-counterfeiting, high-density information storage, intelligent optical sensing and photoresist dye.

Description

Technical Field

[0001] The present invention belongs to the field of multifunctional optical materials, and in particular relates to a multicolor dynamic room temperature phosphorescent pyridinium naphthalene diimide-doped polymer film that can be photothermally programmed and controlled, and its application. Background Art

[0002] Multifunctional optical materials have great application potential in the fields of optical anti-counterfeiting, information storage, optical sensing, photoresist, etc., and have received extensive attention and research. In recent years, optical functional materials with light stimulus response have aroused strong interest among researchers and have made great progress ( Angew. Chem. Int. Ed. 2023, 62 , e202218994; Angew. Chem. Int. Ed. 2023, 62 , e202308848). With the advancement of technology, further endowing light-responsive optical materials with unique functionality to achieve more advanced applications in related optical fields is particularly attractive. In particular, introducing additional stimuli into light-responsive optical functional material systems to develop multifunctional optical materials with programmable multi-stimulus responses is particularly attractive. However, this currently faces significant challenges. Developing new multifunctional light-responsive building blocks will be an important approach to achieving this goal.

[0003] Patent CN118459636A uses commercial rigid polyvinyl alcohol (PVA) as a polymer matrix, which can effectively block oxygen in the air from penetrating into its polymer network. Therefore, the photoresponsive structural units doped in its polymer network can be confined, and the free radicals generated by the light-induced photoresponsive structural units can be stabilized, thereby enabling its doped polymer system to achieve stable photochromism. Moreover, the movement of the photoresponsive structural units confined in its polymer network is reduced, which is beneficial to the efficient and long-life phosphorescence of its doped polymer system. However, it should be noted that the polymer system prepared based on the bipyridinium photoresponsive structural unit in patent CN118459636A only presents structural color changes induced by one stimulus of light excitation and the accompanying dynamic changes in phosphorescence, that is, it fails to achieve multifunctional dynamic optical properties with multiple stimulus responses induced by both light stimulation and other stimuli. In particular, the development of multifunctional optical materials with multiple stimulus responses that can be programmed and coordinated with both light stimulation and thermal stimulation is a problem to be solved. Summary of the Invention

[0004] To address the technical challenges of the prior art, the present invention utilizes molecular engineering strategies to achieve structural control, introducing electron-deficient pyridinium groups into naphthalene diimide building blocks. Based on a simple synthetic method and polymer doping strategy, these building blocks are incorporated into polymer systems to develop photothermally programmable, multicolor, dynamic, room-temperature phosphorescent pyridinium naphthalene diimide-doped polymers. The introduction of the pyridinium group into the building blocks enhances their solubility, and doping into a conventional, rigid polyvinyl alcohol (PVA) matrix addresses the issue of free radical stability. By leveraging the spatial control effect of the pyridinium group and the planarity of naphthalene diimide, thermal manipulation is facilitated to transform photoinduced free radicals from a single-electron state to a radical dimer, enabling simultaneous control of emission color and phosphorescence lifetime, as well as achieving transitions between three structural colors. This invention achieves a unique, photothermally programmable, multicolor, dynamic room-temperature phosphorescence phenomenon, which holds great potential for advanced dynamic anti-counterfeiting, information storage, optical sensing, and photoresist applications.

[0005] The present invention can be implemented through the following technical routes and solutions: A multicolor dynamic room-temperature phosphorescent pyridinium naphthalene diimide-doped polymer that can be photothermally programmed includes a pyridinium naphthalene diimide photoresponsive structural unit having both photochromic and phosphorescent emission functions, such as structural formula (I), and a commercially available rigid polymer matrix polyvinyl alcohol (PVA), such as structural formula (II).

[0006] .

[0007] The preparation process for pyridinium naphthalene diimide-doped polymers with multicolor dynamic room-temperature phosphorescence that can be controlled by photothermal programming is as follows: PVA is dissolved in water at 100°C, an ethanolic solution of the pyridinium naphthalene diimide ion compound is added to the PVA aqueous solution, stirred at 80-100°C for 1-6 hours, and then cooled to room temperature to obtain a uniform aqueous solution of the target doped polymer. The uniform aqueous solution of the target doped polymer is then loaded onto various substrates and dried in an oven (60-100°C) to form a solid functional film of the target polymer.

[0008] Wherein, the mass ratio of the pyridinium naphthalene diimide ion compound to the polyvinyl alcohol (PVA) is 1-100:1000.

[0009] The synthesis method of pyridinium naphthalene diimide ion chemicals is as follows: 1,4,5,8-naphthalenetetracarboxylic dianhydride and 4-aminopyridine, aminomethylpyridine or 3-aminopyridine and N,N-dimethylformamide are added to a round-bottom flask respectively; the reaction mixture is stirred at 150° C. for 10 hours, the resulting precipitate is collected by filtration, and washed with DMF until the washing liquid is clear to obtain pure solids; the resulting solids are then added to an acetonitrile solution with 4-bromo(methyl)phenylboronic acid, and refluxed at 105° C. for 24 hours. The resulting precipitate is filtered, washed with ethanol, and recrystallized from ethanol to obtain a solid.

[0010] The carrier is a glass matrix, a wood matrix, a cloth matrix, or a paper matrix.

[0011] Multicolor dynamic room-temperature phosphorescent pyridinium naphthalene diimide-doped polymers that can be photothermally programmed are used in advanced anti-counterfeiting, information storage, optical sensing, photoresist dyes and other fields. Beneficial effects

[0012] The present invention prepares a multifunctional optical material system with multiple stimulus responses by doping an electron-deficient pyridinium naphthalene diimide light-responsive ionic compound into a rigid polymer system. The multifunctional optical material system with multiple stimulus responses: a) It emits bright light under ultraviolet light, and after the excitation light source is removed, phosphorescence can still be observed with an afterglow lasting about 0.5 s; b) After continuous ultraviolet light exposure, the functional polymer changes color and can also exhibit phosphorescence; c) Upon further heating, the color of the polymer system changes again, exhibiting a different state. Its luminescence under UV light weakens, its color changes significantly, and its afterglow after the excitation light is removed shortens. Subsequently, the functional polymer system is fumigated with water vapor and dried, causing the color to fade and returning the functional polymer material to its initial state.

[0013] This multifunctional, multi-stimulus-responsive optical material system achieves a multi-state mode of programmable control: light regulation, thermal regulation, and solvent recovery, exhibiting unique optical properties. This holds great promise for applications in dynamic advanced anti-counterfeiting, information storage, multi-dimensional optical sensing, photoresist dyes, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 a is a photograph of a film of a pyridinium naphthalene diimide-doped polymer doped with NDI-1 on a glass carrier under natural light, and its fluorescence photograph under 365nm ultraviolet lamp, and its phosphorescence emission photograph after the light is removed, as well as a photograph under natural light after continuous irradiation with 365nm ultraviolet lamp, and its fluorescence photograph under 365nm ultraviolet lamp, and its phosphorescence emission photograph after the light is removed.

[0015] Figure 1 b is a photograph of the NDI-1-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier under natural light, and its fluorescence photograph under 395nm ultraviolet light, and its phosphorescence emission photograph after the light is removed, as well as a photograph under natural light after continuous irradiation with 395nm ultraviolet light, and its fluorescence photograph under 395nm ultraviolet light, and its phosphorescence emission photograph after the light is removed.

[0016] Figure 2 a is a photograph of a film of a pyridinium naphthalene diimide-doped polymer doped with NDI-2 formed on a glass carrier under natural light, and its fluorescence photograph under 365nm ultraviolet lamp irradiation, and its phosphorescence emission photograph after the light is removed, as well as a photograph under natural light after continuous irradiation with 365nm ultraviolet lamp, and its fluorescence photograph under 365nm ultraviolet lamp irradiation, and its phosphorescence emission photograph after the light is removed.

[0017] Figure 2 b is a photograph of the NDI-3-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier under natural light, and its fluorescence photograph under 365nm ultraviolet lamp irradiation, and phosphorescence emission photograph after the light is removed, as well as a photograph under natural light after continuous irradiation with 365nm ultraviolet lamp, and its fluorescence photograph under 365nm ultraviolet lamp irradiation, and phosphorescence emission photograph after the light is removed.

[0018] Figure 3 a is a graph of the phosphorescence lifetime of a polymer doped with NDI-1 and pyridinium naphthalene diimide before and after illumination formed on a glass carrier.

[0019] Figure 3 b is the phosphorescence lifetime diagram of the NDI-2-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier before and after illumination and heating.

[0020] Figure 3 c is the phosphorescence lifetime diagram of the NDI-3-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier before and after illumination and heating.

[0021] Figure 4 a is the fluorescence and phosphorescence emission spectra of the NDI-1-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier before and after irradiation with a 365nm ultraviolet lamp.

[0022] Figure 4 b is the fluorescence and phosphorescence emission spectra of the NDI-2-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier before and after irradiation with a 365nm ultraviolet lamp.

[0023] Figure 4c is the fluorescence and phosphorescence emission spectra of the NDI-3-doped pyridinium naphthalene diimide-doped polymer film formed on a glass carrier before and after irradiation with a 365nm ultraviolet lamp.

[0024] Figure 5 a is the EPR intensity of the NDI-1-doped pyridinium naphthalene diimide-doped polymer film decreases with increasing temperature in the low temperature range of 123K-243K after illumination.

[0025] Figure 5 b is the EPR intensity of the NDI-2-doped pyridinium naphthalene diimide-doped polymer film increases with temperature from low temperature to high temperature after irradiation.

[0026] Figure 5 c is the EPR intensity of the NDI-2-doped pyridinium naphthalene diimide-doped polymer film increases with temperature from low temperature to high temperature after heating.

[0027] Figure 5 d is the EPR intensity of the NDI-3-doped pyridinium naphthalene diimide-doped polymer film increases with temperature from low temperature to high temperature after irradiation.

[0028] Figure 5 e is the EPR intensity of the NDI-3-doped pyridinium naphthalene diimide-doped polymer film increases with temperature from low temperature to high temperature after heating.

[0029] Figure 6 It is an afterglow luminescence image and color change image doped with NDI-1, NDI-2 and NDI-3 on paper as anti-counterfeiting information. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1 Pyridinium naphthalene diimide doped polymer doped with NDI-1, wherein the mass ratio of NDI-1 to PVA is 3:600 In a round-bottom flask, 1,4,5,8-naphthalenetetracarboxylic dianhydride NDA (3.60 g, 13.4 mmol), 4-aminopyridine (3.7 g, 40.2 mmol), and N,N-dimethylformamide (15 ml) were added; the reaction mixture was stirred at 150 ° C for 10 h, the resulting precipitate was collected by filtration, and washed with DMF until the washing liquid was clear to obtain a pure solid; the resulting solid (3.60 g, 8.5 mmol) and 4-bromo(methyl)phenylboronic acid (5.2 g, 21.5 mmol) were then added to an acetonitrile solution (20 ml), heated under reflux at 105 ° C for 24 h, the resulting precipitate was filtered, washed with ethanol, and recrystallized from ethanol to obtain a solid NDI-1.

[0032] In air, 600 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-1 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-1-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0033] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it emits bright blue light. When the excitation light source is removed, it emits orange phosphorescence. Figure 1 Figure a shows the fluorescence and phosphorescence emission of the polymer film. It can be seen that the afterglow time is 0.8 s. After 3 minutes of continuous illumination, the polymer changes from colorless to brownish-yellow. This is because during the illumination process, the polymer film is photoinduced to produce stable free radicals. In addition, the polymer film can be restored to its original colorless state by heating at 65°C or under the stimulation of water vapor. Figure 1 As shown in a. Figure 4 a is the fluorescence and phosphorescence emission spectra of the polymer film. From the spectra, we can see that the maximum fluorescence emission peak and the maximum phosphorescence emission peak are located at 416 nm and 573 nm respectively, with slightly different peak widths. The luminescence lifetime decay diagram of the phosphorescence emission peak at 573 nm is shown in Figure 2. Figure 3 (a) Furthermore, the polymer film can return to its colorless initial state under the stimulation of water vapor. Under 395 nm ultraviolet light excitation, the polymer film exhibits bright blue luminescence. When the excitation light source is removed, yellow phosphorescence is emitted. Figure 1(b) Photographs of the fluorescence and phosphorescence emission of the polymer film show an afterglow duration of up to 1 second. After 3 minutes of continuous illumination, the polymer changes from colorless to brownish-yellow. This is due to the generation of stable free radicals induced by light during illumination. Furthermore, the polymer film can return to its original colorless state upon stimulation with water vapor.

[0034] Example 2: Pyridinium naphthalene diimide doped polymer doped with NDI-2, wherein the mass ratio of NDI-2 to PVA is 3:600. In a round-bottom flask, (3.60 g, 13.4 mmol) 1,4,5,8-naphthalenetetracarboxylic dianhydride NDA and (4.3 g, 40.2 mmol) aminomethylpyridine and N,N-dimethylformamide (15 ml) were added; the reaction mixture was stirred at 150 ° C for 10 h, the resulting precipitate was collected by filtration and washed with DMF until the washing liquid was clear to obtain a pure solid; the resulting solid (3.80 g, 8.5 mmol) and 4-bromo(methyl)phenylboronic acid (5.2 g, 21.5 mmol) were then added to an acetonitrile solution (20 ml), heated under reflux at 105 ° C for 24 h, the resulting precipitate was filtered, washed with ethanol, and recrystallized from ethanol to obtain a solid NDI-2.

[0035] In air, 600 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-2 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-2-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0036] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it emits bright purple light. When the excitation light source is removed, it emits red phosphorescence. Figure 2 a is a photograph of the fluorescence and phosphorescence emission of the polymer film. It can be seen that the afterglow time is 0.1 s. Figure 4 a is the fluorescence and phosphorescence emission spectra of the polymer film. From the spectra, we can see that the maximum fluorescence emission peak and the maximum phosphorescence emission peak are located at 417 nm and 676 nm respectively, with slightly different peak widths. The luminescence lifetime decay diagram of the phosphorescence emission peak at 676 nm is shown in Figure 2. Figure 3 As shown in b. After continuous light exposure, the polymer changes from colorless to dark purple. This is because during the light exposure process, the photoinduced polymer produces stable free radicals, such as Figure 2 a, and the life span becomes shorter as Figure 3b. After further heating, the polymer film changes color from purple to dark reddish-brown. This is because the increased temperature provides energy, enhancing molecular thermal motion and promoting the formation of dimers from free radicals. Furthermore, the polymer film returns to its original colorless state when stimulated by water vapor.

[0037] Example 3 Pyridinium naphthalene diimide doped polymer doped with NDI-3, wherein the mass ratio of NDI-3 to PVA is 3:600 In a round-bottom flask, (3.60 g, 13.4 mmol) 1,4,5,8-naphthalenetetracarboxylic dianhydride NDA and (3.7 g, 40.2 mmol) 3-aminopyridine and N,N-dimethylformamide (20 ml) were added; the reaction mixture was stirred at 150 ° C for 10 h, the resulting precipitate was collected by filtration and washed with DMF until the washing liquid was clear to obtain a pure solid; the resulting solid (3.60 g, 8.5 mmol) and 4-bromo(methyl)phenylboronic acid (5.2 g, 21.5 mmol) were added to an acetonitrile solution (20 ml), heated under reflux at 105 ° C for 24 h, the resulting precipitate was filtered, washed with ethanol, and recrystallized from ethanol to obtain a solid NDI-3.

[0038] In air, 600 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-3 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-3-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0039] The polymer film is colorless under natural light. However, when excited by 365 nm ultraviolet light, it emits pink light and continues to emit orange phosphorescence even after the excitation light source is removed. Figure 2 b is a photograph of the fluorescence and phosphorescence emission of the polymer film. It can be seen that the afterglow time is 0.4 s. Figure 4 c is the fluorescence and phosphorescence emission spectra of the polymer film. As can be seen from the spectra, the maximum fluorescence emission peak and the maximum phosphorescence emission peak are located at 416 nm and 622 nm respectively, with slightly different peak widths. The luminescence decay lifetime diagram of the phosphorescence emission peak at 622 nm is shown in Figure 4. Figure 3 c. After continuous light exposure, the polymer film changes from its initial colorless state to green. This is because during the light exposure process, the light-induced polymer produces stable free radicals. After heating, the polymer film changes from green to dark yellow, as shown in Figure 2b. This is because the temperature increase provides energy, enhancing molecular thermal motion and prompting the free radicals to form dimers. In addition, the polymer film can return to its original colorless state under the stimulation of water vapor.

[0040] Example 4 Pyridinium naphthalene diimide doped polymer doped with NDI-1, wherein the mass ratio of NDI-1 to PVA is 3:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-1 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-1-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0041] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it emits a bright blue luminescence. After the excitation light source is removed, it emits orange phosphorescence with an afterglow time of 0.9 s. With continued illumination, the polymer changes from its initial colorless state to a brownish-yellow color. This is due to the generation of stable free radicals induced by light during illumination. Furthermore, the polymer film can be restored to its original colorless state by heating at 65°C or by exposure to water vapor.

[0042] Example 5 Pyridinium naphthalene diimide doped polymer doped with NDI-1, wherein the mass ratio of NDI-1 to PVA is 1:1000 In air, 1000 mg of PVA was dissolved in 5 ml of 100°C water. Then, 1 mg of NDI-1 was dissolved in 1 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-1-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0043] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits bright blue luminescence. After the excitation light source is removed, it emits orange phosphorescence with an afterglow duration of approximately 1 s. With continued illumination, the polymer changes from its initial colorless state to a pale yellow. The polymer film can be restored to its original colorless state by stimulation with water vapor.

[0044] Example 6 Pyridinium naphthalene diimide doped polymer doped with NDI-1, wherein the mass ratio of NDI-1 to PVA is 10:100 In air, 100 mg of PVA was dissolved in 5 ml of 100°C water. Then, 10 mg of NDI-1 was dissolved in 3 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-1-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0045] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits bright blue luminescence. After the excitation light source is removed, it emits orange phosphorescence with an afterglow time of 0.8 s. With continued illumination, the polymer changes from its initial colorless state to a brownish-yellow color. The polymer film can be restored to its original colorless state by stimulation with water vapor.

[0046] Example 7 Pyridinium naphthalene diimide doped polymer doped with NDI-2, wherein the mass ratio of NDI-2 to PVA is 3:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-2 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-2-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0047] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it emits a bright purple luminescence. After the excitation light source is removed, it emits red phosphorescence with an afterglow time of up to 0.1 s. With continued illumination, the polymer changes from its initial colorless state to a deep purple color. This is due to the generation of stable free radicals induced by light during the illumination process. Furthermore, the polymer film turns dark reddish-brown upon heating at 65°C and then returns to its initial colorless state upon exposure to water vapor.

[0048] Example 8 Pyridinium naphthalene diimide doped polymer doped with NDI-3, wherein the mass ratio of NDI-3 to PVA is 3:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 3 mg of NDI-3 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-3-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0049] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits a pink luminescence. After the excitation light source is removed, it emits orange-red phosphorescence with an afterglow time of up to 0.3 seconds. With continued illumination, the polymer changes color from its initial colorless state to green. This is due to the generation of stable free radicals induced by light during the illumination process. Furthermore, the polymer film turns deep yellow upon heating to 65°C and then returns to its initial colorless state upon exposure to water vapor.

[0050] Example 9 Pyridinium naphthalene diimide doped polymer doped with NDI-1, wherein the mass ratio of NDI-1 to PVA is 6:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 6 mg of NDI-1 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-1-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope cover slip and dried at 60°C to form a film.

[0051] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits blue luminescence. After the excitation light source is removed, it emits orange phosphorescence with an afterglow duration of approximately 0.9 seconds. With continued illumination, the polymer changes from its initial colorless state to a brownish-yellow color. This is due to the generation of stable free radicals induced by light during illumination. Furthermore, the polymer film returns to its initial colorless state upon heating to 65°C or exposure to water vapor.

[0052] Example 10 Pyridinium naphthalene diimide doped polymer doped with NDI-2, wherein the mass ratio of NDI-2 to PVA is 6:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 6 mg of NDI-2 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-2-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0053] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits a purple luminescence. After the excitation light source is removed, it emits red phosphorescence with an afterglow time of approximately 0.04 seconds. With continued illumination, the polymer changes from its initial colorless state to a deep purple color. This is due to the generation of stable free radicals induced by light during the illumination process. Furthermore, the polymer film turns dark reddish-brown upon heating to 65°C and then returns to its initial colorless state upon exposure to water vapor.

[0054] Example 11 Pyridinium naphthalene diimide ionomer doped with NDI-3, wherein the mass ratio of NDI-3 to PVA is 6:300 In air, 300 mg of PVA was dissolved in 5 ml of 100°C water. Then, 6 mg of NDI-3 was dissolved in 2 ml of ethanol. The mixture was added to the PVA solution and stirred at 80°C for 3 hours. After stirring, the reaction was stopped, cooled to room temperature, and filtered to obtain an aqueous solution of NDI-3-doped pyridinium naphthalene diimide ionomer. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0055] The polymer film appears colorless under natural light. When excited by 365 nm ultraviolet light, it exhibits a pink luminescence. After the excitation light source is removed, it emits orange phosphorescence with an afterglow time of approximately 0.3 seconds. With continued illumination, the polymer changes from its initial colorless state to green. This is due to the generation of stable free radicals induced by light during the illumination process. Furthermore, the polymer film turns deep yellow upon heating to 65°C and then returns to its initial colorless state upon exposure to water vapor.

[0056] Comparative Example 1 Pyridinium naphthalene diimide ionomer doped with NDI-1, wherein the mass ratio of NDI-1 to polypyrrolidone PVP is 3:600 In air, 600 mg of PVP and 3 mg of NDI-1 were dissolved in 5 ml of ethanol. After sonication, an ethanol solution of the NDI-1-doped pyridinium naphthalene diimide ionomer was obtained. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0057] The polymer film appears light brown under natural light. When excited by 365 nm ultraviolet light, it exhibits pink luminescence. After the excitation light source is removed, it emits orange-red phosphorescence with an afterglow time of approximately 0.36 s. With continued illumination, the polymer changes from its initial light brown color to dark brown. This is due to the generation of stable free radicals induced by light during the illumination process. Furthermore, the color of the polymer film is largely restored after heating to 65°C, and it fully returns to its original light brown state when exposed to air.

[0058] Comparative Example 2 Pyridinium naphthalene diimide ionomer doped with NDI-2, wherein the mass ratio of NDI-2 to polypyrrolidone PVP is 3:600 In air, 600 mg of PVP and 3 mg of NDI-2 were dissolved in 5 ml of ethanol. After sonication, an ethanol solution of NDI-2-doped pyridinium naphthalene diimide ionomer was obtained. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0059] The polymer film appears light brown under natural light. When excited by 365 nm ultraviolet light, it emits orange light. When the excitation light source is removed, there is no phosphorescence. With continued illumination, the polymer changes from its initial light brown color to a dark purple. This is due to the generation of stable free radicals induced by light during exposure. Furthermore, the polymer film turns dark brown after heating to 65°C and returns to its original light brown state when exposed to air.

[0060] Comparative Example 3 Pyridinium naphthalene diimide ionomer doped with NDI-3, wherein the mass ratio of NDI-3 to polypyrrolidone PVP is 3:600 In air, 600 mg of PVP and 3 mg of NDI-3 were dissolved in 5 ml of ethanol. After sonication, an ethanol solution of NDI-3-doped pyridinium naphthalene diimide ionomer was obtained. A 1 ml drop of this solution was then applied to an ultra-clear glass microscope coverslip and dried at 60°C to form a film.

[0061] The polymer film appears light brown under natural light. When excited by 365 nm ultraviolet light, it emits purple light. When the excitation light source is removed, there is no phosphorescence. With continued illumination, the polymer changes from its initial light brown color to dark green. This is due to the generation of stable free radicals induced by light during exposure. Furthermore, the polymer film turns brown after heating to 65°C, but returns to its original light brown state when exposed to air.

[0062] Example 15: Multi-dimensional advanced anti-counterfeiting applications based on NDI-1, NDI-2, and NDI-3 doped polymer films A petal-shaped pattern was made by using a mixed polymer of NDI-1, NDI-2, and NDI-3 (wherein the ratio of NDI-1, NDI-2, NDI-3 to PVA was 3:600), such as Figure 6 The petal-shaped pattern appears colorless under natural light. Under 365 nm ultraviolet light, the three petals emit blue light of varying brightness. After the excitation light source is removed, they can emit red and orange phosphorescence, with an afterglow time visible to the naked eye of about 0.44 s. After continuous illumination, the petals prepared from the doped polymers of NDI-2 and NDI-3 show a more obvious color change under natural light. Under 365 nm ultraviolet light, the three petals emit slightly weakened blue light of varying brightness. After the excitation light source is removed, the doped polymers containing NDI-1 and NDI-3 can emit orange phosphorescence, with an afterglow time visible to the naked eye of about 0.4 s. The petals of the doped polymer containing NDI-2 have almost no phosphorescence. Further heating of the illuminated samples revealed another color shift in the petals made from the NDI-2 and NDI-3 doped polymers. Under 365 nm ultraviolet light, the three petals still emitted varying degrees of blue light. After removing the excitation light source, the doped polymers containing NDI-1 and NDI-3 continued to emit orange phosphorescence, while the petals made from the NDI-2 doped polymer showed almost no phosphorescence. This demonstrates that the doped polymers of NDI-1, NDI-2, and NDI-3 achieve a multi-stimulus-responsive anti-counterfeiting scheme with dynamically adjustable photochromism, thermochromism, and room-temperature phosphorescence.

Claims

1. A multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide-doped polymer film that can be photothermally programmed, characterized in that: The doped polymer film is obtained by doping a pyridinium naphthalene diimide ion compound with polyvinyl alcohol and then loading it on a matrix carrier, wherein the pyridinium naphthalene diimide ion compound is first synthesized from 1,4,5,8-naphthalenetetracarboxylic dianhydride and 4-aminopyridine, aminomethylpyridine or 3-aminopyridine to form a naphthalene diimide derivative, which is then reacted with 4-bromo(methyl)phenylboronic acid to obtain the obtained product.

2. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 1, characterized in that: The structural formula of the pyridinium naphthalene diimide ion compound is shown in formula (I): 。 3. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 1, characterized in that: The synthesis method of pyridinium naphthalene diimide ion chemicals is as follows: 1,4,5,8-naphthalenetetracarboxylic dianhydride and 4-aminopyridine, aminomethylpyridine or 3-aminopyridine and N,N-dimethylformamide are added to a round-bottom flask respectively; the reaction mixture is stirred at 150° C. for 10 hours, the resulting precipitate is collected by filtration, and washed with DMF until the washing liquid is clear to obtain pure solids; the resulting solids are then added to an acetonitrile solution with 4-bromo(methyl)phenylboronic acid, and refluxed at 105° C. for 24 hours. The resulting precipitate is filtered, washed with ethanol, and recrystallized from ethanol to obtain a solid.

4. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 1, characterized in that: The doping mass ratio of the pyridinium naphthalene diimide ion compound to the polyvinyl alcohol is 1-100:1000.

5. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 1, characterized in that: The preparation process of pyridinium naphthalene diimide doped polymer film is as follows: polyvinyl alcohol is dissolved in 100°C water, and then an ethanol solution of pyridinium naphthalene diimide ion compound is added to the polyvinyl alcohol aqueous solution and stirred, and then cooled to room temperature to obtain a uniform aqueous solution of the target doped polymer loaded on the matrix carrier, and dried in an oven to form a solid functional film of the target polymer.

6. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 5, characterized in that: The stirring temperature is 80-100℃, the stirring time is 1-6 h; the drying temperature is 60-100℃.

7. The multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 5, characterized in that: The matrix carrier is glass, wood, cloth, and paper.

8. An application of the multi-color dynamic room temperature phosphorescent pyridinium naphthalene diimide doped polymer film capable of photothermal programmable control according to claim 1, characterized in that: The doped polymer film is used in the fields of high-level anti-counterfeiting, high-density information storage, intelligent optical sensing, and photoresist dyes.

Images