Preparation method of AIEgen-doped PVA hydrogel with electroluminescent color-changing properties

Abstract

The present invention belongs to the technical field of optoelectronic materials, and specifically relates to a method for preparing an AIEgen-doped PVA hydrogel with electrofluorescent color-changing properties. (1) FcMe-TPE is synthesized; (2) a 0.1-0.5 mmol / L FcMe-TPE solution is prepared using dimethyl sulfoxide as a solvent; (3) a PVA hydrogel solution is prepared; (4) the FcMe-TPE solution and the PVA hydrogel solution are uniformly mixed, and then 1-ethyl-3-methylimidazolium tetrafluoroborate is added, and the resulting mixed solution is frozen and then thawed to prepare an AIEgen-doped PVA hydrogel with electrofluorescent color-changing properties. The AIEgen-doped PVA hydrogel with electrofluorescent color-changing properties prepared using the preparation method of the present invention has a fluorescence color that changes from transparent to blue-green under a relatively low applied voltage, has a rapid response, and has a strong fluorescence signal.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and specifically relates to a method for preparing an AIEgen-doped PVA hydrogel with electroluminescent color-changing properties. Background Art

[0002] In recent years, fluorescent hydrogels have attracted widespread attention due to their huge application potential in the fields of sensors, smart displays, and information encryption. In order to apply hydrogels to a variety of smart applications, it is necessary to integrate superior photoelectric responses. Electrofluorescence refers to the change in fluorescence intensity or color of a material under the action of an applied voltage, and the electrical signal and the fluorescence signal have the characteristics of high sensitivity and visualization. However, most electrofluorescence materials have the problem of fluorescence quenching in the aggregated state, that is, aggregation leads to luminescence quenching, resulting in weak fluorescence signals and low fluorescence switching contrast during the color change process, which is not conducive to basic research and application development. Introducing aggregation-induced luminescence (AIEgen) into hydrogels can obtain electrofluorescence materials with high fluorescence switching contrast, injecting new vitality into the development of this field. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing an AIEgen-doped PVA hydrogel with electroluminescent color-changing properties. The electroluminescent color-changing material prepared by this method has a strong fluorescent signal in the aggregated state and a high fluorescence switching contrast.

[0004] The preparation method of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties of the present invention comprises the following steps:

[0005] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine and acetylferrocene are dissolved in anhydrous ethanol and reacted to synthesize the aggregation-induced luminescent material (1E)-1-((1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazide)ethyl)ferrocene, i.e., FcMe-TPE;

[0006] (2) Using dimethyl sulfoxide as solvent, prepare a 0.1-0.5 mmol / L FcMe-TPE solution;

[0007] (3) dissolving polyvinyl alcohol in a mixed solvent consisting of dimethyl sulfoxide and water and stirring the mixture to prepare a PVA hydrogel solution;

[0008] (4) The FcMe-TPE solution prepared in step (2) and the PVA hydrogel solution prepared in step (3) are evenly mixed, and then 1-ethyl-3-methylimidazolium tetrafluoroborate is added. The resulting mixed solution is frozen and then thawed to prepare an AIEgen-doped PVA hydrogel with electroluminescent color-changing properties.

[0009] in:

[0010] In step (1), the molar ratio of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to acetylferrocene is 1:1.1-1:1.5.

[0011] The reaction conditions in step (1) are as follows: reflux at 75° C. for 6-8 hours under a nitrogen atmosphere, and then the resulting solution is placed at 5° C. for 24 hours. After the reaction is completed, the solution is filtered to prepare FcMe-TPE.

[0012] In step (1), 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine and acetylferrocene are respectively dissolved in anhydrous ethanol, and then the two mixed solutions are respectively subjected to ultrasonic treatment until completely dissolved, and then the anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine is added dropwise to the anhydrous ethanol solution of acetylferrocene to react, wherein the mass volume ratio of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to anhydrous ethanol in the anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to anhydrous ethanol is 0.324:50, and the unit is g / mL, and the mass volume ratio of acetylferrocene to anhydrous ethanol in the anhydrous ethanol solution of acetylferrocene is 0.200-0.270:50, and the unit is g / mL.

[0013] The preparation method of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine in step (1) comprises the following steps:

[0014] ① Add triphenylethylene bromide and p-formylphenylboronic acid to a reaction vessel, then add toluene, potassium carbonate aqueous solution and tetrabutylammonium bromide, stir at room temperature for 30 minutes under a nitrogen atmosphere to dissolve it, then add tetrakis(triphenylphosphine)palladium, react at 90°C for 24 hours. After the reaction is completed, pour the reaction solution into water and extract it three times with ethyl acetate. The organic layer is dried over anhydrous sodium sulfate and the solvent is removed by vacuum rotary evaporation. Finally, ethyl acetate and petroleum ether with a volume ratio of 1:10 are used as eluents and purified by silica gel chromatography to obtain the intermediate product 4-(1,2,2-triphenylvinyl)benzaldehyde, namely TPE-CHO;

[0015] ② The intermediate product TPE-CHO prepared in step ① was dissolved in ethanol and ultrasonically stirred until completely dissolved. Hydrazine hydrate was dissolved in ethanol to prepare a hydrazine hydrate solution. TPE-CHO was added dropwise to the hydrazine hydrate solution and reacted for 3 hours. After the reaction was completed, the mixture was allowed to stand for 24 hours for crystallization and filtered to obtain 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine, i.e., TPE-NH2.

[0016] in:

[0017] In step ①, the molar ratio of brominated triphenylethylene to p-formylphenylboronic acid is 2:3.

[0018] The concentration of the potassium carbonate aqueous solution in step ① is 2 mol / L; the volume ratio of toluene to the potassium carbonate aqueous solution is 80:25; the mass volume ratio of brominated triphenylethylene to the potassium carbonate aqueous solution is 6.7:25, and the unit is g / mL.

[0019] In step ①, the molar ratio of brominated triphenylethylene to tetrabutylammonium bromide is 10:1.

[0020] In step ①, the molar ratio of brominated triphenylethylene to tetrakis(triphenylphosphine)palladium is 20:0.0173.

[0021] The mass volume ratio of TPE-CHO to ethanol in step ② is 0.48:35, and the unit is g / mL.

[0022] In step ②, the volume ratio of hydrazine hydrate to ethanol in the hydrazine hydrate solution is 1:100.

[0023] The mass volume ratio of TPE-CHO to hydrazine hydrate in step ② is 0.24:100, and the unit is g / μL.

[0024] In step (3), the volume ratio of dimethyl sulfoxide to water is 4:6-7:3.

[0025] In step (3), the mass volume ratio of polyvinyl alcohol to the mixed solvent consisting of dimethyl sulfoxide and water is 1:12.5, and the unit is g / mL.

[0026] The stirring speed of the stirring reaction in step (3) is 1000 r / min, the stirring reaction temperature is 75-90° C., and the stirring reaction time is 2-3 hours.

[0027] In step (4), the volume ratio of the FcMe-TPE solution to the PVA hydrogel solution is 1:10-1:5.

[0028] In step (4), the volume ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to the PVA hydrogel solution is 1:10-1:5.

[0029] The freezing temperature in step (4) is -20°C and the freezing time is 24 hours.

[0030] The thawing temperature in step (4) is room temperature and the thawing time is 12 hours.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The method for preparing the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in the present invention has easy-to-control process parameters and simple operation. The prepared AIEgen-doped PVA hydrogel with electroluminescent color-changing properties has stable performance.

[0033] (2) The AIEgen-doped PVA hydrogel with electroluminescent color-changing properties prepared by the preparation method described in the present invention has both aggregation-induced emission characteristics and redox properties, overcoming the problem of luminescence quenching caused by aggregation, and can be applied to electroluminescent color-changing materials and devices.

[0034] (3) The AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared by the preparation method described in the present invention changes the fluorescence color from transparent to blue-green under a relatively low applied voltage, with a rapid response, high contrast, and strong fluorescence signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the NMR spectrum of the aggregation-induced luminescence material FcMe-TPE prepared in Example 1;

[0036] Figure 2 This is a photo of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties obtained in Example 1;

[0037] Figure 3 It is a gel forming mold;

[0038] Figure 4 is a schematic diagram of realizing an electroluminescent color changing device;

[0039] Figure 5 This is a photo of the AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared in Example 1 before and after pressurization under ultraviolet light;

[0040] Figure 6 This is a photo of the AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared in Example 2 before and after pressurization under ultraviolet light;

[0041] Figure 7 This is the NMR spectrum of 4-(1,2,2-triphenylvinyl)benzaldehyde;

[0042] Figure 8 This is the NMR spectrum of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine;

[0043] Figure 9 This is a physical picture of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties prepared in Example 3 before and after pressurization under ultraviolet light. DETAILED DESCRIPTION

[0044] The present invention is further described below with reference to the examples.

[0045] The preparation method of the raw material 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine used in Example 1-3 and Comparative Example 1-2 consists of the following steps:

[0046] ① Add 6.7 g (20 mmol) of triphenylethylene bromide and 4.5 g (30 mmol) of p-formylphenylboronic acid to a three-necked flask. Then, add 80 mL of toluene, 25 mL (2 mol / L) aqueous potassium carbonate solution, and 0.64 g (2 mmol) of tetrabutylammonium bromide. Stir at room temperature under a nitrogen atmosphere for 30 minutes to allow complete dissolution. Add 0.02 g (0.0173 mmol) of tetrakis(triphenylphosphine)palladium to the three-necked flask and react at 90°C for 24 hours. After the reaction is complete, pour the reaction solution into water and extract three times with ethyl acetate. The organic layer is dried over anhydrous sodium sulfate and the solvent is removed by rotary evaporation under reduced pressure. Finally, purify the product by silica gel chromatography using ethyl acetate and petroleum ether in a volume ratio of 1:10 as the eluent to obtain the intermediate product, 4-(1,2,2-triphenylethenyl)benzaldehyde (TPE-CHO). Figure 7 The H NMR spectrum shown proves that TPE-CHO was successfully synthesized.

[0047] ② Weigh 0.48 g of the intermediate product TPE-CHO prepared in step ① and dissolve it in 35 mL of ethanol. Ultrasonicate, heat, and stir repeatedly for 25 minutes until completely dissolved. Take 200 μL of hydrazine hydrate and dissolve it in 20 mL of ethanol. Add it to a three-necked flask and install a reflux device. Slowly add TPE-CHO dropwise to the hydrazine hydrate solution (along the wall). The reaction is completed after 3 hours. After the reaction is completed, let it stand for 24 hours to crystallize, and filter it to obtain 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (TPE-NH2). Figure 8 The H NMR spectrum shown in the figure proves that TPE-NH2 was successfully synthesized.

[0048] Example 1

[0049] The method for preparing the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in Example 1 comprises the following steps:

[0050] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (0.324 g) and acetylferrocene (0.200 g) were dissolved in ethanol (50 mL) respectively. The two mixed solutions were ultrasonically treated until completely dissolved. Then, the anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine was added dropwise to the anhydrous ethanol solution of acetylferrocene to react, and refluxed at 75°C for 6 hours under a nitrogen atmosphere. The resulting solution was placed in an environment of 5°C for 24 hours and filtered to obtain a light brown solid powder of (1E)-1-((1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazide)ethyl)ferrocene (FcMe-TPE). Figure 1 The H NMR spectrum shown proves that the FcMe-TPE aggregation-induced luminescence was successfully synthesized.

[0051] (2) Using dimethyl sulfoxide as solvent, prepare a 0.1 mmol / L FcMe-TPE solution.

[0052] (3) PVA (8 g) was dissolved in a mixed solvent of dimethyl sulfoxide (40 mL) and water (60 mL), and the mixture was reacted at 75° C. for 2.5 hours under rapid stirring at a stirring speed of 1000 r / min to obtain a PVA hydrogel solution.

[0053] (4) The FcMe-TPE solution (200 μL) in step (2) and the PVA hydrogel solution (2 mL) in step (3) were mixed evenly, 1-ethyl-3-methylimidazolium tetrafluoroborate (200 μL) was added, and the resulting mixed solution was poured into Figure 3 The mold shown was frozen at -20°C for 24 hours and then thawed at room temperature for 12 hours to produce AIEgen-doped PVA hydrogel with electroluminescent color-changing properties. Figure 2 This is a real picture of AIEgen-doped PVA hydrogel with electroluminescent color-changing properties.

[0054] Figure 4 The device shown is used to achieve electroluminescent color change. Specifically, two sheets of indium tin oxide (ITO) conductive glass are used as the two electrodes. The AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared in Example 1 is sandwiched between the two sheets of ITO conductive glass. The device is connected to an electrochemical workstation, and a 1V voltage is applied through the electrochemical workstation for 10 seconds. After the pressure is applied, the gel emits blue-green fluorescence under ultraviolet light, as shown in FIG. Figure 5 This indicates that the gel has a response time of less than 10 seconds, and the fluorescence signal before and after pressurization is significantly different, from no fluorescence before pressurization to blue-green fluorescence after pressurization. This indicates that the gel can be used as an electroluminescent material and in electroluminescent devices.

[0055] Example 2

[0056] The preparation method of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in Example 2 comprises the following steps:

[0057] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (0.324 g) and acetylferrocene (0.220 g) were dissolved in ethanol (50 mL) respectively. The two mixed solutions were ultrasonically treated until they were completely dissolved. The anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine was then added dropwise to the anhydrous ethanol solution of acetylferrocene to react, and the mixture was refluxed at 75°C for 7 hours under a nitrogen atmosphere. The resulting solution was placed in an environment of 5°C for 24 hours and filtered to obtain a light brown solid powder of (1E)-1-((1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazineidene)ethyl)ferrocene (FcMe-TPE).

[0058] (2) Using dimethyl sulfoxide as solvent, prepare a 0.2 mmol / L FcMe-TPE solution.

[0059] (3) PVA (8 g) was dissolved in a mixed solvent of dimethyl sulfoxide (50 mL) and water (50 mL), and the mixture was reacted at 83° C. for 3 hours under rapid stirring at a stirring speed of 1000 r / min to obtain a PVA hydrogel solution.

[0060] (4) The FcMe-TPE solution (400 μL) in step (2) and the PVA hydrogel solution (2 mL) in step (3) were mixed evenly, 1-ethyl-3-methylimidazolium tetrafluoroborate (400 μL) was added, and the resulting mixed solution was poured into Figure 3 The mold shown was frozen at -20°C for 24 hours and then thawed at room temperature for 12 hours to produce AIEgen-doped PVA hydrogel with electroluminescent color-changing properties.

[0061] Figure 4 The device shown is used to achieve electroluminescent color change. Specifically, two sheets of indium tin oxide (ITO) conductive glass are used as the two electrodes. The AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared in Example 2 is sandwiched between the two sheets of ITO conductive glass. The device is connected to an electrochemical workstation, through which a 1V voltage is applied for 10 seconds. After the pressure is applied, the gel emits blue-green fluorescence under ultraviolet light, as shown in FIG. Figure 6 This indicates that the gel has a response time of less than 10 seconds, and the fluorescence signal before and after pressurization is significantly different, from no fluorescence before pressurization to blue-green fluorescence after pressurization. This indicates that the gel can be used as an electroluminescent material and in electroluminescent devices.

[0062] Example 3

[0063] The preparation method of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in Example 3 comprises the following steps:

[0064] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (0.324 g) and acetylferrocene (0.270 g) were dissolved in ethanol (50 mL) respectively. The two mixed solutions were ultrasonically treated until they were completely dissolved. The anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine was then added dropwise to the anhydrous ethanol solution of acetylferrocene to react, and the mixture was refluxed at 75°C for 8 hours under a nitrogen atmosphere. The resulting solution was placed in an environment of 5°C for 24 hours and filtered to obtain a light brown solid powder of (1E)-1-((1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazideethyl)ferrocene (FcMe-TPE).

[0065] (2) Using dimethyl sulfoxide as solvent, prepare a 0.5 mmol / L FcMe-TPE solution.

[0066] (3) PVA (8 g) was dissolved in a mixed solvent of dimethyl sulfoxide (70 mL) and water (30 mL), and the mixture was reacted at 90° C. for 2 hours under rapid stirring at a stirring speed of 1000 r / min to obtain a PVA hydrogel solution.

[0067] (4) The FcMe-TPE solution (300 μL) in step (2) and the PVA hydrogel solution (2 mL) in step (3) were mixed evenly, 1-ethyl-3-methylimidazolium tetrafluoroborate (300 μL) was added, and the resulting mixed solution was poured into Figure 3 The mold shown was frozen at -20°C for 24 hours and then thawed at room temperature for 12 hours to produce AIEgen-doped PVA hydrogel with electroluminescent color-changing properties.

[0068] Figure 4 The device shown is used to achieve electroluminescent color change. Specifically, two sheets of indium tin oxide (ITO) conductive glass are used as the two electrodes. The AIEgen-doped PVA hydrogel with electroluminescent color change properties prepared in Example 3 is sandwiched between the two sheets of ITO conductive glass. The device is connected to an electrochemical workstation, and a 1V voltage is applied through the electrochemical workstation for 10 seconds. After the pressure is applied, the gel emits blue-green fluorescence under ultraviolet light, as shown in FIG. Figure 9 This indicates that the gel has a response time of less than 10 seconds, and the fluorescence signal before and after pressurization is significantly different, from no fluorescence before pressurization to blue-green fluorescence after pressurization. This indicates that the gel can be used as an electroluminescent material and in electroluminescent devices.

[0069] Comparative Example 1

[0070] The preparation method of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in Comparative Example 1 comprises the following steps:

[0071] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (0.324 g) and acetylferrocene (0.200 g) were dissolved in ethanol (50 mL) respectively. The two mixed solutions were ultrasonically treated until they were completely dissolved. The anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine was then added dropwise to the anhydrous ethanol solution of acetylferrocene to react, and refluxed at 75°C under a nitrogen atmosphere for 6 hours. The resulting solution was placed in an environment of 5°C for 24 hours and filtered to obtain a light brown solid powder of FcMe-TPE.

[0072] (2) Using dimethyl sulfoxide as solvent, prepare a 0.1 mmol / L FcMe-TPE solution.

[0073] (3) PVA (8 g) was dissolved in a mixed solvent of dimethyl sulfoxide (40 mL) and water (60 mL), and the mixture was reacted at 75° C. for 2.5 hours under rapid stirring at a stirring speed of 1000 r / min to obtain a PVA hydrogel solution.

[0074] (4) The FcMe-TPE solution (2 mL) in step (2) and the PVA hydrogel solution (2 mL) in step (3) were mixed evenly, 1-ethyl-3-methylimidazolium tetrafluoroborate (200 μL) was added, and the resulting mixed solution was poured into Figure 3 The mold shown was frozen at -20°C for 24 hours and then thawed at room temperature for 12 hours, but it was found that no stable hydrogel could be formed.

[0075] Comparative Example 2

[0076] The preparation method of the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties described in Comparative Example 2 comprises the following steps:

[0077] (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine (0.324 g) and acetylferrocene (0.220 g) were dissolved in ethanol (50 mL) respectively. The two mixed solutions were ultrasonically treated until they were completely dissolved. The anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine was then added dropwise to the anhydrous ethanol solution of acetylferrocene to react, and refluxed at 75°C for 7 hours under a nitrogen atmosphere. The resulting solution was placed in an environment of 5°C for 24 hours and filtered to obtain a light brown solid powder of FcMe-TPE.

[0078] (2) Using dimethyl sulfoxide as solvent, prepare a 0.2 mmol / L FcMe-TPE solution.

[0079] (3) PVA (8 g) was dissolved in a mixed solvent of dimethyl sulfoxide (50 mL) and water (50 mL), and the mixture was reacted at 83° C. for 3 hours under rapid stirring at a stirring speed of 1000 r / min to obtain a PVA hydrogel solution.

[0080] (4) The FcMe-TPE solution (400 μL) in step (2) and the PVA hydrogel solution (2 mL) in step (3) were mixed evenly, 1-ethyl-3-methylimidazolium tetrafluoroborate (2 mL) was added, and the resulting mixed solution was frozen at -20°C for 24 hours and then thawed at room temperature for 12 hours. It was found that no stable hydrogel could be formed.

[0081] In Comparative Example 1, the volume ratio of the FcMe-TPE solution to the PVA hydrogel solution was 1:1. In Comparative Example 2, the volume ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to the PVA hydrogel solution was 1:1. When too much FcMe-TPE solution or 1-ethyl-3-methylimidazolium tetrafluoroborate was added, the PVA concentration dropped significantly, preventing the formation of a stable gel network.

Claims

1. A method for preparing an AIEgen-doped PVA hydrogel with electroluminescent color-changing properties, characterized by: It consists of the following steps: (1) 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine and acetylferrocene were dissolved in anhydrous ethanol and reacted to synthesize the aggregation-induced luminescent material (1E)-1-((1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazide)ethyl)ferrocene, namely FcMe-TPE; (2) Using dimethyl sulfoxide as solvent, prepare a 0.1-0.5 mmol / L FcMe-TPE solution; (3) dissolving polyvinyl alcohol in a mixed solvent consisting of dimethyl sulfoxide and water and stirring the mixture to prepare a PVA hydrogel solution; (4) The FcMe-TPE solution prepared in step (2) and the PVA hydrogel solution prepared in step (3) are uniformly mixed, and then 1-ethyl-3-methylimidazolium tetrafluoroborate is added. The resulting mixed solution is frozen and then thawed to prepare an AIEgen-doped PVA hydrogel with electroluminescent color-changing properties; in: In step (4), the volume ratio of FcMe-TPE solution to PVA hydrogel solution is 1:10-1:5; In step (4), the volume ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to the PVA hydrogel solution is 1:10-1:

5.

2. The method for preparing the AIEgen-doped PVA hydrogel having electroluminescent color-changing properties according to claim 1, characterized in that: In step (1), the molar ratio of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to acetylferrocene is 1:1.1-1:1.

5.

3. The method for preparing the AIEgen-doped PVA hydrogel having electroluminescent color-changing properties according to claim 1, characterized in that: The reaction conditions in step (1) are to reflux at 75°C for 6-8 hours under a nitrogen atmosphere, and then place the resulting solution at 5°C for 24 hours. After the reaction is completed, the solution is filtered to prepare FcMe-TPE.

4. The method for preparing the AIEgen-doped PVA hydrogel having electroluminescent color-changing properties according to claim 1, characterized in that: In step (1), 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine and acetylferrocene are respectively dissolved in anhydrous ethanol, and then the two mixed solutions are ultrasonically treated until they are completely dissolved, and then the anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine is added dropwise to the anhydrous ethanol solution of acetylferrocene to react, wherein the mass volume ratio of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to anhydrous ethanol in the anhydrous ethanol solution of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine to anhydrous ethanol is 0.324:50, expressed in g / mL, and the mass volume ratio of acetylferrocene to anhydrous ethanol in the anhydrous ethanol solution of acetylferrocene is 0.200-0.270:50, expressed in g / mL.

5. The method for preparing the AIEgen-doped PVA hydrogel having electroluminescent color-changing properties according to claim 1, characterized in that: The preparation method of 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine in step (1) comprises the following steps: ① Add triphenylethylene bromide and p-formylphenylboronic acid to a reaction vessel, then add toluene, potassium carbonate aqueous solution and tetrabutylammonium bromide, stir at room temperature for 30 minutes under a nitrogen atmosphere to dissolve it, then add tetrakis(triphenylphosphine)palladium, react at 90°C for 24 hours. After the reaction is completed, pour the reaction solution into water and extract it three times with ethyl acetate. The organic layer is dried over anhydrous sodium sulfate and the solvent is removed by vacuum rotary evaporation. Finally, ethyl acetate and petroleum ether with a volume ratio of 1:10 are used as eluents and purified by silica gel chromatography to obtain the intermediate product 4-(1,2,2-triphenylvinyl)benzaldehyde, namely TPE-CHO; ② The intermediate product TPE-CHO prepared in step ① was dissolved in ethanol and ultrasonically stirred until completely dissolved. Hydrazine hydrate was dissolved in ethanol to prepare a hydrazine hydrate solution. TPE-CHO was added dropwise to the hydrazine hydrate solution and reacted for 3 hours. After the reaction was completed, the mixture was allowed to stand for 24 hours for crystallization and filtered to obtain 1-(4-(1,2,2-triphenylvinyl)benzylidene)hydrazine, i.e., TPE-NH2.

6. The method for preparing the AIEgen-doped PVA hydrogel having electroluminescent color-changing properties according to claim 5, characterized in that: In step ①, the molar ratio of brominated triphenylethylene to p-formylphenylboronic acid is 2:3; The concentration of the potassium carbonate aqueous solution in step ① is 2 mol / L; the volume ratio of toluene to the potassium carbonate aqueous solution is 80:25; the mass volume ratio of brominated triphenylethylene to the potassium carbonate aqueous solution is 6.7:25, the unit is g / mL; In step ①, the molar ratio of brominated triphenylethylene to tetrabutylammonium bromide is 10:1; In step ①, the molar ratio of brominated triphenylethylene to tetrakis(triphenylphosphine)palladium is 20:0.0173; In step ②, the mass volume ratio of TPE-CHO to ethanol is 0.48:35, expressed in g / mL; In step 2, the volume ratio of hydrazine hydrate to ethanol in the hydrazine hydrate solution is 1:100; The mass volume ratio of TPE-CHO to hydrazine hydrate in step ② is 0.24:100, and the unit is g / μL.

7. The method for preparing the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties according to claim 1, characterized in that: In step (3), the volume ratio of dimethyl sulfoxide to water is 4:6-7:3; In step (3), the mass volume ratio of polyvinyl alcohol to the mixed solvent consisting of dimethyl sulfoxide and water is 1:12.5, and the unit is g / mL; The stirring speed of the stirring reaction in step (3) is 1000 r / min, the stirring reaction temperature is 75-90° C., and the stirring reaction time is 2-3 hours.

8. The method for preparing the AIEgen-doped PVA hydrogel with electroluminescent color-changing properties according to claim 1, characterized in that: The freezing temperature in step (4) is -20°C, and the freezing time is 24 hours; the thawing temperature in step (4) is room temperature, and the thawing time is 12 hours.

Images