Self-repairing room-temperature phosphorescent elastomer based on waterborne polyurethane as well as preparation method and application of self-repairing room-temperature phosphorescent elastomer

Abstract

The invention relates to the technical field of polymer room-temperature phosphorescent materials, in particular to a self-repairing room-temperature phosphorescent elastomer based on waterborne polyurethane and a preparation method and application thereof, and the specific preparation steps include: 1) synthesis of self-repairing waterborne polyurethane and 2) preparation of a self-repairing room-temperature phosphorescent waterborne polyurethane elastomer material. A self-repairing waterborne polyurethane elastomer material is taken as a polymer matrix for constructing a rigid network, and is combined with various micromolecular organic light-emitting units through physical doping, so that the self-repairing room-temperature phosphorescent waterborne polyurethane elastomer material with strong self-healing capability, excellent optical performance and good mechanical tensile property is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer room temperature phosphorescent materials, and particularly relates to a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane, a preparation method thereof, and an application thereof. Background Art

[0002] Metal-free materials with room temperature phosphorescence (RTP) have attracted extensive attention in multiple fields such as bioimaging, organic optoelectronics, information encryption, and anti-counterfeiting due to their remarkable optical properties. Organic room temperature phosphorescent materials that can be reversibly stretched under external force and have excellent optical / mechanical properties have great application potential in the fields of flexible electronics and photonics. Compared with traditional metal-based phosphorescent materials or crystal systems, polymer matrices not only have low toxicity, low cost, and processability, but also can be functionalized through flexible molecular design, laying a foundation for expanding the application of room temperature phosphorescent materials in the field of flexible optoelectronics. However, existing polymer room temperature phosphorescent materials still face many challenges in practical applications. Most of the reported room temperature phosphorescent polymers lack flexibility and stretchability, and there are also obvious deficiencies in the durability and self-healing ability of the materials, which greatly limits their long-term stability and reliability in complex environments. Therefore, it is particularly necessary to develop a room temperature phosphorescent elastomer material with self-healing function, which can not only effectively extend the service life of the material, reduce the use and maintenance costs of the material, but also further expand its application scope to meet the urgent needs of high-performance materials in practical applications.

[0003] Waterborne polyurethane (WPU) materials not only have the excellent properties of traditional polyurethanes, but also use water as a dispersion medium, greatly reducing the use of organic solvents, thereby reducing environmental pollution and harm to the human body, and improving the green environmental protection of the materials. By introducing reversible dynamic covalent bonds, such as disulfide bonds, Diels-Alder (D-A) reactions, borate bonds, hydrazone bonds, diselenide bonds, etc., as well as dynamic non-covalent bonds such as hydrogen bonds, metal coordination bonds, π-π stacking, and ionic bonds, waterborne polyurethane can be given unique self-healing properties. Based on the ability of self-healing waterborne polyurethane itself to spontaneously repair physical damages (such as cuts and scratches) and restore the original function and structure, they show strong application prospects in multiple fields such as coatings, wearable electronic devices, biomedical materials, and aerospace materials.

[0004] In view of the above defects, the creators of the present invention have finally obtained the present invention through long-term research and practice. Summary of the Invention

[0005] The object of the present invention is to solve the problems that most existing room-temperature phosphorescent polymers lack flexibility and stretchability, and there are also obvious deficiencies in the durability and self-healing ability of the materials, which greatly limit their long-term stability and reliability in complex environments, and provide a self-healing room-temperature phosphorescent elastomer based on waterborne polyurethane, a preparation method thereof and an application thereof.

[0006] To achieve the above object, the present invention discloses a preparation method of a self-healing room-temperature phosphorescent elastomer based on waterborne polyurethane, comprising the following steps:

[0007] S1, adding diisocyanate to dried polytetrahydrofuran, fully mixing and then adding a catalyst, heating and stirring for reaction to obtain a prepolymer;

[0008] S2, adding a chain extender to the prepolymer obtained in step S1 and continuing the reaction, and adding an organic solvent to adjust the viscosity of the system;

[0009] S3, adding triethylamine to the reaction system in step S2 for neutralization;

[0010] S4, waiting for the reaction system in step S3 to cool, adding ultrapure water, and stirring at high speed for emulsification to obtain a waterborne polyurethane emulsion;

[0011] S5, adding an organic small molecule chromophore to the waterborne polyurethane emulsion obtained in step S4, fully mixing, vacuum degassing, and transferring to a mold for drying to obtain a self-healing room-temperature phosphorescent elastomer.

[0012] In the step S1, the polytetrahydrofuran is any one or a combination of several of PTMEG-250, PTMEG-1000, and PTMEG-2000; the diisocyanate is any one or a combination of several of 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate; the molar ratio of the diisocyanate to the polytetrahydrofuran is 2:1 to 2.5:1; the catalyst is any one or a combination of several of stannous octoate, stannous oleate, and dibutyltin dilaurate; the dosage of the catalyst is 0.1 wt% to 1.0 wt%.

[0013] In the step S1, the drying process of the polytetrahydrofuran is as follows: placing the polytetrahydrofuran in a three-necked flask, removing water at 110-120 °C for 1-2 h in a vacuum environment to remove the moisture in the polytetrahydrofuran.

[0014] In the step S1, the heating and stirring reaction temperature is 75-80 °C, the reaction time is 3-4 h, and the stirring method is magnetic stirring.

[0015] In the step S2, the chain extender is 2,2-dimethylolpropionic acid or a combination of 1,4-butanediol and adipic dihydrazide. In the combination of 1,4-butanediol and adipic dihydrazide, the molar ratio of 1,4-butanediol or adipic dihydrazide to 2,2-dimethylolpropionic acid is 1:19 to 3:7; the molar ratio of the chain extender to the diisocyanate is 1:2.5 to 1:2;

[0016] The reaction temperature is 75 to 85 °C, the reaction time is 3 to 4 h, and the stirring method is magnetic stirring; the organic solvent is any one of anhydrous N,N-dimethylformamide, anhydrous N,N-dimethylacetamide, and anhydrous acetone.

[0017] In the step S3, the molar ratio of triethylamine to the chain extender in the step S2 is 1:1; the neutralization temperature is 25 to 35 °C, and the neutralization reaction time is 30 to 40 min.

[0018] In the step S4, the dosage of ultrapure water satisfies: making the solid content of the emulsion 25 wt% to 35 wt%; the high-speed stirring emulsification temperature is 25 to 35 °C; the emulsification time is 1 to 12 h.

[0019] In the step S5, the organic small molecule chromophore is any one or a combination of 1-hydroxypyrene, 1-methylpyrene, 1-pyreneboronic acid, 7-hydroxy-4-methylcoumarin, 6H-indolo[2,3-b]quinoxaline, 7H-dibenzo[c,g]carbazole, 9H-9H,-3,3,-bicarbazole, 3,6-diphenyl-9H-carbazole, 1,8-naphthalenedicarboximide, etc. The doping ratio of the organic small molecule chromophore is 0.01 wt% to 5 wt%;

[0020] The mixing temperature is 20 to 30 °C, the mixing time is 0.5 to 2 h; the vacuum defoaming temperature is 20 to 30 °C, the defoaming time is 0.5 to 2 h; the mold is a polytetrafluoroethylene mold, the drying temperature is 60 to 80 °C, and the drying time is 12 to 48 h.

[0021] The present invention also discloses a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane prepared by the above preparation method and the application of this self-healing room temperature phosphorescent elastomer based on waterborne polyurethane in self-healing dynamic anti-counterfeiting encryption labels and flexible wearable devices.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The present invention does not require complex and cumbersome chemical synthesis steps. By a simple physical blending method, a variety of commercially available organic small molecule chromophores are directly introduced into the synthesized aqueous polyurethane matrix. Through the rigid network of aqueous polyurethane and the internal hydrogen bond interaction, room temperature phosphorescence emission of the organic small molecule chromophores is achieved. The raw materials of the present invention are easily available and inexpensive, and large-area colorful flexible room temperature phosphorescent materials can be easily prepared, while enabling large-scale production.

[0024] 2. Based on the excellent self-healing performance and tensile performance of aqueous polyurethane itself, the present invention breaks through the limitations of traditional polymer room temperature phosphorescent materials, enabling them to still have good optical properties in the stretched state. At the same time, when subjected to external forces such as cutting and scratching, based on hydrogen bond interaction, the material can spontaneously repair under heating conditions, extending the service life of the material, meeting the usage requirements of multiple scenarios, and showing great application potential in the field of flexible wearable devices;

[0025] 3. The self-healing room temperature phosphorescent elastomer material based on aqueous polyurethane of the present invention has good luminescent properties. After continuous excitation by high-intensity 365 nm ultraviolet light, it can exhibit multi-color room temperature phosphorescence emission such as yellow, green, and red. Its unique photoactivated room temperature phosphorescence property enables it to be applied to self-healing dynamic anti-counterfeiting encryption labels;

[0026] 4. The self-healing room temperature phosphorescent elastomer material based on aqueous polyurethane of the present invention meets the requirements of green environmental protection and sustainable development. Description of the Drawings

[0027] Figure 1 Synthesis schematic diagram of the aqueous polyurethane in Comparative Example 1 ;

[0028] Figure 2 Chemical structural formulas of each organic small molecule chromophore;

[0029] Figure 3 Aqueous polyurethane in Example 1 Aqueous polyurethane in Comparative Example 1 and aqueous polyurethane in Comparative Example 2 Infrared spectra;

[0030] Figure 4 Self-healing room temperature phosphorescent elastomer IDQA@ obtained in Example 1 and self-healing room temperature phosphorescent elastomer IDQA@ obtained in Comparative Examples 1-2 and Phosphorescence spectra after magnifying the phosphorescence intensity by 20 times;

[0031] Figure 5 Self-healing room temperature phosphorescent elastomer IDQA@ obtained in Example 1 and Comparative Examples 5-6 Phosphorescence spectra diagram;

[0032] Figure 6 For Example 1 and Comparative Example 4, self-healing room-temperature phosphorescent elastomers IDQA@ doped with different contents of 6H-indolo[2,3-b]quinoxaline Phosphorescence spectra diagram;

[0033] Figure 7 For the self-healing room-temperature phosphorescent elastomer IDQA@ obtained in Example 1 Phosphorescence intensity change spectrum diagram with the change of ultraviolet light irradiation time;

[0034] Figure 8 For the self-healing room-temperature phosphorescent elastomer IDQA@ obtained in Example 1 Stress-strain curve diagram;

[0035] Figure 9 For the self-healing room-temperature phosphorescent elastomer IDQA@ obtained in Example 1 Self-healing room-temperature phosphorescent elastomer MBL@ obtained in Example 2 Self-healing room-temperature phosphorescent elastomer HPY@ obtained in Example 3 Self-healing room-temperature phosphorescent elastomer DBCZ@ obtained in Example 4 Self-healing room-temperature phosphorescent elastomer DPCZ@ obtained in Example 5 Self-healing room-temperature phosphorescent elastomer UCZ@ obtained in Example 6 Phosphorescence spectra diagram;

[0036] Figure 10 For the self-healing room-temperature phosphorescent elastomer IDQA@ obtained in Example 1 Self-healing room-temperature phosphorescent elastomer MBL@ obtained in Example 2 Self-healing room-temperature phosphorescent elastomer HPY@ obtained in Example 3 Self-healing room-temperature phosphorescent elastomer DBCZ@ obtained in Example 4 Self-healing room-temperature phosphorescent elastomer DPCZ@ obtained in Example 5 Self-healing room-temperature phosphorescent elastomer UCZ@ obtained in Example 6 Phosphorescence photos after the 365 nm ultraviolet excitation light source is turned off;

[0037] Figure 11 For the self-healing room-temperature phosphorescent elastomer MBL@ obtained in Example 2 Self-healing photos at different times, and self-healing room-temperature phosphorescent elastomer IDQA@ obtained in Example 1 Phosphorescence photos after the 365 nm ultraviolet excitation light source is turned off under the tensile state. Detailed implementation mode

[0038] The following further elaborates on the above and additional technical features and advantages of the present invention in conjunction with the accompanying drawings.

[0039] Example 1

[0040] (1) Pre-dry the glassware and magnetic stir bar required. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stir bar, a condenser reflux tube, and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait until the temperature drops to 30 °C, dropwise add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and after thorough mixing, dropwise add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0041] (2) Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH), mix them thoroughly and add them to the prepolymer system obtained in step (2). Subsequently, add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0042] (3) Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, stir and neutralize for 30 min; add 30 mL of deionized water, stir at high speed until a completely uniformly dispersed aqueous polyurethane emulsion is obtained, and name it

[0043] (4) Weigh 30 mg of 6H-indolo[2,3-b]quinoxaline, add it to 1 mL of DMF solution and sonicate until completely dissolved. Subsequently, add 10 g of aqueous polyurethane, sonicate and mix, then degas under vacuum. Then transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven to dry at 60 °C for 24 h to obtain a self-healing room temperature phosphorescent elastomer IDQA@

[0044] Example 2

[0045] (1) Pre-dry the glassware and magnetic stir bar required. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stir bar, a condenser reflux tube, and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait until the temperature drops to 30 °C, dropwise add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and after thorough mixing, dropwise add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0046] (2) Weigh 1.1401 g of 2,2-bis(hydroxymethyl)propionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH). After thorough mixing, add them to the prepolymer system obtained in step (2). Subsequently, add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0047] (3) Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, and stir for neutralization for 30 min; add 30 mL of deionized water, and stir at high speed for emulsification until a completely uniformly dispersed aqueous polyurethane emulsion is obtained, and name it

[0048] (4) Weigh 100 mg of 7-hydroxy-4-methylcoumarin, add 1 mL of DMF solution and sonicate until completely dissolved. Subsequently, add 10 g of aqueous polyurethane, sonicate and mix, then perform vacuum degassing. Then transfer it to a dumbbell-shaped polytetrafluoroethylene mold, and place it in an oven at 60 °C for drying for 24 h to obtain a self-healing room-temperature phosphorescent elastomer MBL@

[0049] Example 3

[0050] (1) Dry the required glassware and magnetic stirrers in advance. Weigh 11 g of polytetrahydrofuran with a relative molecular weight of 1000 (PTMEG-1000), add it to a three-necked flask equipped with a magnetic stirrer, a condenser reflux tube and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; when the temperature drops to 30 °C, dropwise add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI). After thorough mixing, dropwise add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0051] (2) Weigh 1.1401 g of 2,2-bis(hydroxymethyl)propionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH). After thorough mixing, add them to the prepolymer system obtained in step (2). Subsequently, add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0052] (3) Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, and stir for neutralization for 30 min; add 30 mL of deionized water, and stir at high speed for emulsification until a completely uniformly dispersed aqueous polyurethane emulsion is obtained, and name it

[0053] (4) Weigh 30 mg of 1-hydroxypyrene, add 1 mL of DMF solution, and ultrasonicate until completely dissolved. Then add 10 g of waterborne polyurethane, ultrasonically mix, and degas under vacuum. Subsequently, transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven at 60 °C for 24 h to obtain a self-healing room-temperature phosphorescent elastomer HPY@

[0054] Example 4

[0055] (1) Dry the required glassware and magnetic stirrers in advance. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stirrer, a condenser reflux tube, and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait for the temperature to drop to 30 °C, and gradually add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI). After thorough mixing, gradually add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0056] (2) Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH). After thorough mixing, add them to the prepolymer system obtained in step (2). Then add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0057] (3) Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, stir and neutralize for 30 min; add 30 mL of deionized water, and stir at high speed for emulsification until a completely dispersed and uniform waterborne polyurethane emulsion is obtained, and name it

[0058] (4) Weigh 30 mg of 7H-dibenzo[c,g]carbazole, add 1 mL of DMF solution, and ultrasonicate until completely dissolved. Then add 10 g of waterborne polyurethane, ultrasonically mix, and degas under vacuum. Subsequently, transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven at 60 °C for 24 h to obtain a self-healing room-temperature phosphorescent elastomer DBCZ@

[0059] Example 5

[0060] (1) Pre-dry the glassware and magnetic stir bar required. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stir bar, a reflux condenser and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait until the temperature drops to 30 °C, dropwise add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and after thorough mixing, dropwise add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0061] (2) Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH), mix them thoroughly and add them to the prepolymer system obtained in step (2). Subsequently, add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0062] (3) Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, stir and neutralize for 30 min; add 30 mL of deionized water, stir at high speed until a completely dispersed and uniform aqueous polyurethane emulsion is obtained, and name it

[0063] (4) Weigh 30 mg of 3,6-diphenylcarbazole, add it to 1 mL of DMF solution and ultrasonicate until completely dissolved. Subsequently, add 10 g of aqueous polyurethane, ultrasonically mix and then degas under vacuum. Then transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven at 60 °C for drying for 24 h to obtain a self-healing room-temperature phosphorescent elastomer DPCZ@

[0064] Example 6

[0065] (1) Pre-dry the glassware and magnetic stir bar required. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stir bar, a reflux condenser and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait until the temperature drops to 30 °C, dropwise add 5.7718 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and after thorough mixing, dropwise add 100 μL of dibutyltin dilaurate (DBTDL), and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0066] (2) Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH), mix them thoroughly and add them to the prepolymer system obtained in step (2). Subsequently, add 15 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0067] (3) Cool the mixture to 30°C in a water bath, add 0.860 g of triethylamine, and stir for neutralization for 30 min; add 30 mL of deionized water, and stir at high speed to emulsify until a completely dispersed and uniform aqueous polyurethane emulsion is obtained, which is named

[0068] (4) Weigh 30 mg of 9H-9H,-3,3,-bicarbazole, add 1 mL of DMF solution and ultrasonicate until completely dissolved, then add 10 g of aqueous polyurethane, ultrasonically mix and vacuum degas, then transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven at 60 °C to dry for 24 h to obtain the self-healing room temperature phosphorescent elastomer BiCZ@

[0069] Comparative Example 1

[0070] (1) Dry the glassware and stirring magnet required in advance. Weigh 11g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnet, a condenser reflux tube and a thermometer, heat and stir at 120°C for 1h to remove moisture; when the temperature drops to 30°C, add 4.890g of isophorone diisocyanate (IPDI) dropwise, after sufficient mixing, add 100μL of dibutyltin dilaurate (DBTDL) dropwise, and react at 80°C with stirring for 3h to obtain a prepolymer;

[0071] (2) Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.2613 g of adipic dihydrazide (ADH), mix thoroughly and add to the prepolymer system obtained in step 2), then add 12 mL of anhydrous DMF to adjust the viscosity, and continue the reaction for 3 h when the temperature in the system stabilizes at 80° C.;

[0072] (3) Cool the mixture to 30°C in a water bath, add 0.860 g of triethylamine, and stir for neutralization for 30 min; add 30 mL of deionized water, and stir at high speed to emulsify until a completely dispersed and uniform aqueous polyurethane emulsion is obtained, which is named

[0073] (4) Weigh 30 mg of 6H-indolo[2,3,b]quinoxaline, add 1 mL of DMF solution and ultrasonicate until completely dissolved, then add 10 g of aqueous polyurethane, ultrasonically mix and vacuum degas, then transfer it to a dumbbell-shaped polytetrafluoroethylene mold and place it in an oven at 60 °C to dry for 24 h to obtain the self-healing room temperature phosphorescent elastomer IDQA@

[0074] Comparative Example 2

[0075] (1)Pre-dry the glassware and magnetic stir bar required. Weigh 11 g of polytetrahydrofuran (PTMEG-1000) with a relative molecular weight of 1000, add it to a three-necked flask equipped with a magnetic stir bar, a condenser reflux tube and a thermometer, heat and stir under vacuum at 120 °C for 1 h to remove moisture; wait until the temperature drops to 30 °C, and add 4.890 g of isophorone diisocyanate (IPDI) dropwise. After thorough mixing, add 100 μL of dibutyltin dilaurate (DBTDL) dropwise, and stir and react at 80 °C for 3 h to obtain a prepolymer;

[0076] (2)Weigh 1.1401 g of 2,2-dimethylolpropionic acid (DMPA) and 0.1352 g of 1,4-butanediol (BDO). After thorough mixing, add them to the prepolymer system obtained in step (2). Then add 12 mL of anhydrous DMF to adjust the viscosity. When the temperature in the system stabilizes at 80 °C, continue the reaction for 3 h;

[0077] (3)Use a water bath to cool down to 30 °C, add 0.860 g of triethylamine, stir and neutralize for 30 min; add 30 mL of deionized water, and stir at high speed to emulsify until a completely dispersed and uniform aqueous polyurethane emulsion is obtained, and name it

[0078] (4)Weigh 30 mg of 6H-indolo[2,3-b]quinoxaline, add it to 1 mL of DMF solution and ultrasonicate until completely dissolved. Then add 10 g of aqueous polyurethane, ultrasonically mix and degas under vacuum. Then transfer it to a dumbbell-shaped polytetrafluoroethylene mold, and place it in an oven at 60 °C for drying for 24 h to obtain a self-healing room temperature phosphorescent elastomer IDQA@

[0079] By comparing the phosphorescent properties of the self-healing room temperature phosphorescent elastomers obtained in Example 1 and Comparative Examples 1-2, it was found that the type of diisocyanate has a significant effect on the luminescent properties of the self-healing room temperature phosphorescent elastomer based on aqueous polyurethane. Compared with the irregular isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate has a more regular rigid structure, which promotes microphase separation and fixes the small molecule chromophore in the hard segment of the aqueous polyurethane, thereby inhibiting the triplet exciton transition of the organic small molecule chromophore and realizing room temperature phosphorescent emission. Introducing multiple hydrogen bond interactions by changing the type of chain extender can also enhance the room temperature phosphorescent emission of organic small molecule chromophores to a certain extent.

[0080] Comparative Example 3

[0081] The difference between this example and Example 1 is that the polytetrahydrofuran used has a molecular weight of 250 and a dosage of 2.75 g, and other processes are the same. The room temperature phosphorescent material obtained based on this aqueous polyurethane does not have self-healing properties.

[0082] Comparative Example 4

[0083] The difference between this example and Example 1 is that the dosages of 6H-indolo[2,3-b]quinoxaline of the organic small molecule chromophore are 1 mg, 10 mg, 50 mg, 100 mg, and 300 mg respectively, and other processes are the same.

[0084] As Figure 6 shown, by comparing the phosphorescence properties of the self-healing room temperature phosphorescent elastomers obtained in Example 1 and Comparative Example 4, it was found that IDQA@ with a doping content of 30 mg has the best luminescence performance.

[0085] Comparative Example 5

[0086] The difference between this example and Example 1 is that the dosages of dimethylolpropionic acid (DMPA), adipic dihydrazide (ADH), and triethylamine are 1.2274 g, 0.0871 g, and 0.9611 g respectively, and other processes are the same.

[0087] Comparative Example 6

[0088] The difference between this example and Example 1 is that the dosages of dimethylolpropionic acid (DMPA), adipic dihydrazide (ADH), and triethylamine are 1.2071 g, 0.1742 g, and 0.9106 g respectively, and other processes are the same.

[0089] As Figure 5 shown, by comparing Example 1 with Comparative Examples 5-6, it was found that as the dosage of the multiple hydrogen bond extender ADH increased, the synthesized self-healing room temperature phosphorescent elastomer showed enhanced luminescence.

[0090] Figure 1 is a schematic diagram of the synthesis of self-healing waterborne polyurethane, which specifically illustrates the preparation process of waterborne polyurethane and its chemical structural formula.

[0091] Figure 2 are the chemical structural formulas of various commercially available small molecule chromophores and do not require synthesis.

[0092] Figure 3 is the waterborne polyurethane in Example 1 the waterborne polyurethane in Comparative Example 1 and the waterborne polyurethane in Comparative Example 2 infrared spectra, in which the characteristic absorption peak of the -NCO group at 2270 cm -1 completely disappeared, indicating that the diisocyanate had completely participated in the reaction. The peaks at 3320 cm -1 and 1531 cm -1 correspond to the stretching vibration and bending vibration of N-H in the urethane group (or urea group) respectively. 2850 cm -1The doublet at 2940 cm -1 is attributed to the stretching vibrations of -CH 3 and -CH 2 . The absorption peaks at 1240 cm-1 and 1100 cm -1 correspond to the symmetric and asymmetric stretching vibrations of the ether bond (C–O–C) in the PTMEG soft segment, respectively. The C=O peak in the carbamate group (or urea group) is located at 1710 cm -1 .

[0093] Figure 4 It shows that the self-healing room-temperature phosphorescent elastomer synthesized based on waterborne polyurethane in Example 1 has the optimal optical properties. The symmetric molecular structure of HMDI is conducive to promoting the formation of an ordered arrangement of hydrogen bonds in the hard segment. Through hydrogen bonding, the intermolecular vibration can be effectively inhibited, and the non-radiative transition of triplet excitons can be inhibited by the rigid network structure.

[0094] Figure 5 Fig. shows the phosphorescence spectra of the self-healing room-temperature phosphorescent elastomers based on waterborne polyurethane in Example 1 and Comparative Examples 5-6. With the increase in the dosage of adipic dihydrazide (ADH), the room-temperature phosphorescence intensity of the obtained self-healing room-temperature phosphorescent elastomer gradually increases.

[0095] Figure 6 Fig. shows the phosphorescence spectra of the self-healing room-temperature phosphorescent elastomer IDQA@ doped with different contents of 6H-indolo[2,3-b]quinoxaline . With the increase in the doping content, its phosphorescence emission intensity gradually increases and then decreases. When the dosage of 6H-indolo[2,3-b]quinoxaline is 30 mg, it has the best luminescence performance. Due to aggregation-induced quenching, when the dosage of 6H-indolo[2,3-b]quinoxaline continues to increase, the phosphorescence intensity decreases.

[0096] Figure 7 It shows that the self-healing room-temperature phosphorescent elastomer obtained based on waterborne polyurethane in Example 1 has special photoactivated room-temperature phosphorescence emission. Its phosphorescence emission intensity increases with the increase in the ultraviolet light irradiation time and reaches the maximum value at about 150 s. Its luminescence mechanism is related to the consumption of oxygen. Under continuous ultraviolet light irradiation, the triplet oxygen in the waterborne polyurethane matrix is converted into singlet oxygen, thus shielding the quenching effect of oxygen and realizing phosphorescence emission. Within a certain period of time after photoactivation, due to the re-permeation of oxygen, the phosphorescence disappears, and when ultraviolet light continues to irradiate and activate, the phosphorescence appears. This special photoactivated room-temperature phosphorescence property enables it to be applied to dynamic anti-counterfeiting labels.

[0097] Figure 8 It shows that the self-healing room-temperature phosphorescent elastomer obtained based on waterborne polyurethane in Example 1 has good mechanical properties. ​

[0098] Figure 9 For the phosphorescence spectra of the self-healing room-temperature phosphorescent elastomers based on waterborne polyurethane in Examples 1-6, the positions of their phosphorescence emission peaks correspond to their luminescent colors. In Example 3, there are two obvious emission peaks, and the position of its maximum emission peak is around 410 nm. However, after continuous irradiation with high-intensity ultraviolet light, it exhibits red room-temperature phosphorescence emission, which is related to the luminescence lifetimes at different wavelengths. The phosphorescence lifetime of the red emission peak at 625 nm is longer, so red phosphorescence emission can be observed with the naked eye after the excitation light source is turned off.

[0099] Figure 10 The phosphorescence photos taken before and after the 365-nm excitation light source is turned off for Examples 1-6 show multicolor room-temperature phosphorescence emission.

[0100] Figure 11 The self-healing performance of the prepared self-healing room-temperature phosphorescent elastomers based on waterborne polyurethane and the phosphorescence photos under tensile conditions are shown. Due to the hydrogen bond interaction inside the waterborne polyurethane, the self-healing room-temperature phosphorescent elastomer based on waterborne polyurethane obtained in Example 2 can self-heal the surface damage after a deep scratch on the surface. The scratch gradually disappears, showing good self-healing properties, which expands the further application of polymer room-temperature phosphorescent materials.

[0101] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. A method for preparing a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane, characterized in that: The following steps are involved: S1, adding diisocyanate to the dried polytetrahydrofuran, adding a catalyst after thorough mixing, heating and stirring to react, and obtaining a prepolymer; S2, adding a chain extender to the prepolymer obtained in step S1 to continue the reaction, and adding an organic solvent to adjust the viscosity of the system; S3, adding triethylamine to the reaction system in step S2 for neutralization; S4, after the reaction system in step S3 is cooled, ultrapure water is added, and emulsified by high-speed stirring to obtain an aqueous polyurethane emulsion; S5, adding an organic small molecule chromophore to the aqueous polyurethane emulsion obtained in step S4, vacuum degassing after complete mixing, transferring to a mold and drying to obtain a self-healing room temperature phosphorescent elastomer.

2. The method for preparing a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In the step S1, the polytetrahydrofuran is any one or a combination of PTMEG-250, PTMEG-1000, and PTMEG-2000; the diisocyanate is any one or a combination of 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate; the molar ratio of diisocyanate to polytetrahydrofuran is 2:1 to 2.5:1; the catalyst is any one or a combination of stannous octoate, stannous oleate, and dibutyltin dilaurate; and the amount of the catalyst is 0.01wt% to 1wt%.

3. The method for preparing a self-repairing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In step S1, the drying process of polytetrahydrofuran is as follows: polytetrahydrofuran is placed in a three-necked flask, and dehydrated at 110-120° C. for 1-2 hours in a vacuum environment to remove moisture in the polytetrahydrofuran.

4. The method for preparing a self-repairing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In the step S1, the heating and stirring reaction temperature is 75-80° C., the reaction time is 3-4 hours, and the stirring method is magnetic stirring.

5. The method for preparing a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In the step S2, the chain extender is a combination of 2,2-dimethylol propionic acid or 1,4-butanediol and adipic acid dihydrazide, wherein the molar ratio of 1,4-butanediol or adipic acid dihydrazide to 2,2-dimethylol propionic acid is 1:19 to 3:7; and the molar ratio of the chain extender to the diisocyanate is 1:2.5 to 1:2; The reaction temperature is 75-85° C., the reaction time is 3-4 hours, and the stirring method is magnetic stirring; the organic solvent is any one of anhydrous N,N-dimethylformamide, anhydrous N,N-dimethylacetamide, and anhydrous acetone.

6. The method for preparing a self-repairing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In the step S3, the molar ratio of triethylamine to the chain extender in the step S2 is 1:1; the neutralization temperature is 25-35° C., and the neutralization reaction time is 30-40 min.

7. The method for preparing a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In step S4, the amount of ultrapure water used satisfies: the solid content of the emulsion is 25wt% to 35wt%; the high-speed stirring emulsification temperature is 25 to 35°C; and the emulsification time is 1 to 12 hours.

8. The method for preparing a self-healing room temperature phosphorescent elastomer based on waterborne polyurethane according to claim 1, characterized in that: In the step S5, the organic small molecule chromophore is any one or a combination of 1-hydroxypyrene, 1-methylpyrene, 1-pyreneboric acid, 7-hydroxy-4-methylcoumarin, 6H-indolo[2,3,b]quinoxaline, 7H-dibenzo[c,g]carbazole, 9H-9H,-3,3,-dicarbazole, 3,6-diphenyl-9H-carbazole, 1,8-naphthalene diimide, and the doping ratio of the organic small molecule chromophore is 0.01wt% to 5wt%; The mixing temperature is 20-30°C, and the mixing time is 0.5-2h; the vacuum degassing temperature is 20-30°C, and the degassing time is 0.5-2h; the mold is a polytetrafluoroethylene mold, the drying temperature is 60-80°C, and the drying time is 12-48h.

9. A self-healing room temperature phosphorescent elastomer based on waterborne polyurethane prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the waterborne polyurethane-based self-healing room temperature phosphorescent elastomer as claimed in claim 9 in self-healing dynamic anti-counterfeiting encryption labels and flexible wearable devices.

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