Light-driven MXene-coated W18O49-PU self-healing transparent film as well as preparation method and application thereof
By introducing MXene@W18O49 hybrid into the transparent film and combining it with the thermoplastic PU matrix, the balance between transparency and thermal insulation properties of the light-driven self-healing film is solved, and efficient self-healing and high transparency are achieved, suitable for flexible wearable electronic devices and indoor thermal management of large buildings.
Patent Information
- Application Number
- CN202510852163.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-08-12
AI Technical Summary
Existing light-driven self-healing films are difficult to balance between transparency and thermal insulation properties, and are prone to shortening device life due to damage, which cannot meet the needs of flexible wearable electronic devices and smart windows.
The MXene@W18O49 hybrid is combined with the thermoplastic PU matrix to achieve self-healing through the light driving mechanism to prepare a light-driven MXene@W18O49-PU self-healing transparent film. Using MXene's high thermal conductivity and photothermal conversion efficiency, combined with the light absorption characteristics of W18O49, the film's self-healing and transparency are enhanced.
It realizes high-efficiency light-driven self-healing ability, high transparency and ultra-strong toughness, and is suitable for flexible wearable electronic devices and indoor thermal management of large buildings, showing versatility and broad application potential.
Smart Images
Figure CN120464183A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of functional new materials, and specifically relates to a light-driven MXene@W 18 O 49 -PU self-healing transparent film and its preparation method and application. Background Art
[0002] Today, air cooling systems consume 15% of global energy to maintain thermal comfort in indoor environments. Windows and skylights are the least efficient components of the building envelope in terms of passive insulation within buildings, so achieving both high transparency and high thermal insulation performance in glass remains a significant challenge. Current approaches to this problem utilize insulating glass units (IGUs) with air or gas fill. However, the high thermal barrier performance of such IGUs requires a large gap thickness between the glass panes, which in turn is constrained by gas convection, the number of glass panes, and their construction. On the other hand, the use of thinner vacuum insulated glass units is limited by near-perfect seal integrity and the associated high cost. Low-emissivity silver and other functional thin-film glass coatings have been shown to reduce energy losses due to blackbody-like electromagnetic emissions from room-temperature building interiors. However, they capture only a small fraction of the escaping energy, potentially sacrificing transparency in the visible range.
[0003] With the rapid advancement of technology, stimuli-responsive thin films have emerged as a new class of advanced functional materials, attracting widespread attention from both academia and industry in diverse applications, including wearable electronics, smart windows, and anti-counterfeiting measures. However, like other conventional thin films, these films are susceptible to accidental rupture or wear, which inevitably shortens the device lifespan and compromises its safety. To address this limitation, many researchers are working to develop biologically inspired self-healing materials that can restore their original function after accidental damage. Generally speaking, self-healing materials can be triggered by internal or external stimuli to repair themselves, either automatically or non-automatically. Among these healing mechanisms, light-driven processes are one of the most promising due to their ability to achieve contactless, remote operation, and precise control. This is particularly advantageous for wearable electronics and smart windows, which require rapid and non-invasive repair.
[0004] Embedding fillers with solar-thermal conversion properties into polymer matrices is a key strategy for achieving light-driven self-healing composite films. To achieve efficient self-healing, photothermal fillers must possess strong light absorption and superior photothermal conversion across a broad spectral range. MXene possesses near-100% photothermal conversion efficiency and high thermal conductivity, while its abundant surface terminals allow for modification without compromising its inherent physical properties. These properties make MXene a promising photothermal filler for a variety of photoresponsive applications. Therefore, incorporating MXene into the preparation of light-driven self-healing composite films is of urgent importance for the development of light-driven, healable transparent films. Summary of the Invention
[0005] The purpose of the present invention is to provide a light-driven MXene@W 18 O 49 -PU self-healing transparent film and its preparation method and application.
[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A light-driven MXene@W 18 O 49 -PU self-healing transparent film, which includes a thermoplastic PU (TPU, thermoplastic polyurethane) matrix and MXene@W embedded therein 18 O 49 Hybrid, MXene@W 18 O 49 The mass percentage of the hybrid in the thermoplastic PU matrix is 0.02~1%.
[0007] A light-driven MXene@W 18 O 49 -The preparation method of PU self-healing transparent film is as follows: (1) Disperse MXene nanosheets evenly in water, then add W 18 O 49 Nanowires, stirred evenly, and dried to obtain MXene@W 18 O 49 Hybrid; wherein, by mass ratio, W 18 O 49 ∶MXene=(1~3)∶(1~3) (2) MXene@W 18 O 49 The hybrid was dispersed in acetone to obtain MXene@W 18 O 49 / acetone dispersion; wherein, based on mass volume ratio, MXene@W 18 O 49Hybrid: acetone = (7~35) mg: (3~5) mL; (3) Thermoplastic PU was prepared by a two-step method under a protective atmosphere: the first step was prepolymerization, and the second step was chain extension reaction; after the chain extension reaction, MXene@W was added. 18 O 49 / acetone dispersion, stir evenly; (4) Pour the reactants obtained in step (3) into the mold and solidify to obtain light-driven MXene@W 18 O 49 -PU self-healing transparent film.
[0008] Preferably, in step (3), a prepolymerization reaction is carried out using polyol, isocyanate, catalyst and solvent as raw materials, and then a chain extender is added to carry out a chain extension reaction.
[0009] Preferably, the specific process of step (3) is: (3.1) Place the polyol in a reaction vessel and stir at 100-120°C for 0.5-3h; (3.2) Lower the temperature of the system obtained in step (3.1) to 60-80°C. After the temperature stabilizes, add isocyanate, catalyst, and solvent to the above reaction vessel in sequence and perform prepolymerization reaction under stirring for 1-3 hours. (3.3) Lower the temperature of the system obtained in step (3.2) to 35-50°C. After the temperature stabilizes, add the chain extender to the above reaction vessel and carry out the chain extension reaction for 10-60 minutes under stirring conditions. (3.4) After the chain extension reaction is completed, the system temperature is maintained constant and MXene@W 18 O 49 / acetone dispersion was added dropwise into the above reaction vessel and stirred until uniform; Step (3) is carried out entirely under protective atmosphere.
[0010] Preferably, the polyol is polytetrahydrofuran, the isocyanate is diisocyanate, the catalyst is dibutyltin dilaurate, the solvent is ethyl acetate, and the chain extender is 2-hydroxyethyl disulfide.
[0011] Preferably, in terms of mass-to-volume ratio, polytetrahydrofuran: diisocyanate: dibutyltin dilaurate: ethyl acetate: 2-hydroxyethyl disulfide = (16-24) g: (11.2-12.6) mL: (45-60) μL: (4-6) mL: (3-4.5) mL.
[0012] Preferably, the curing temperature is 50-80°C and the curing time is 20-30 hours.
[0013] A light-driven MXene@W 18 O 49 -Application of PU self-healing transparent films in wearable electronic devices, indoor thermal management of large buildings or anti-counterfeiting measures.
[0014] In the present invention, MXene nanosheets and W 18 O 49 The nanowires can be prepared using existing technologies, and the raw materials and conditions for preparing TPU can also use existing technologies.
[0015] Beneficial effects: The film prepared by the present invention has excellent light-driven self-healing ability, high transparency and super toughness, and also exhibits multifunctionality, such as: efficient photothermal conversion efficiency and cooling performance, and has broad application potential in flexible wearable electronic devices, indoor thermal management of large buildings and anti-counterfeiting measures. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The Mxene nanosheets prepared in Example 3, W 18 O 49 Nanowires, MXene@W 18 O 49 SEM image of the hybrid.
[0017] Figure 2 MXene nanosheets and W prepared in Example 3 18 O 49 UV-visible-near-infrared absorption spectra of nanowires in aqueous solution.
[0018] Figure 3 The light transmittance of the PUMW4 films of different thicknesses prepared in the present invention in the visible light region.
[0019] Figure 4 The tensile stress-strain performance diagram (a) and columnar statistical results (b) of the PUMW0-PUMW5 film with a thickness of 1 mm prepared in the present invention.
[0020] Figure 5 Photothermal conversion performance: (a) PUMW0-PUMW5 film with a thickness of 1 mm prepared by the present invention at 0.45 W cm -2 (a) shows the temperature rise curve of the sample under the irradiation of NIR light (λ=808nm) of different intensities. (b) shows the relationship between the temperature rise (ΔT) and the irradiation power density of the PUMW4 and PUM3 films with a thickness of 1 mm prepared by the present invention after irradiation of NIR light (λ=808nm) of different intensities for 5 minutes.
[0021] Figure 6A photo of a 200 μm thick PUMW4 film prepared in the present invention coated on a volunteer's hand (left) and infrared thermal imaging after 1 minute of sunlight exposure (right). The dotted box indicates the coated area.
[0022] Figure 7 Cooling performance simulation results: (a) is a real outdoor cooling performance test photo of the experimental group and the blank control group, and (b) is a cooling performance comparison chart of the experimental group and the blank control group.
[0023] Figure 8 A diagram showing the light-driven self-healing effect of a scratched 1 mm thick PUMW4 film prepared in the present invention (scale bar is 100 μm).
[0024] Figure 9 Mechanical self-healing performance results: (a) PUMW4 film with a thickness of 1 mm prepared by the present invention in its original intact state, scratched state, and at 0.9 W cm -2 Stress-strain curves after near-infrared light irradiation for 3 min and 5 min, (b) histogram of the mechanical self-healing efficiency of the PUMW4 film with a thickness of 1 mm prepared in the present invention. DETAILED DESCRIPTION
[0025] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, rather than all of them. Based on the described embodiments, all other embodiments derived by those skilled in the art without requiring creative effort are intended to fall within the scope of protection of the present invention.
[0026] Example 1
[0027] A light-driven MXene@W 18 O 49 -The preparation method of PU self-healing transparent film is as follows: (1) MXene nanosheets were synthesized on Ti3AlC2 precursor using a selective etching process: First, 1 g of LiF was dissolved in 20 mL of concentrated HCl solution (36 wt%) and transferred to a 50 mL polytetrafluoroethylene liner and magnetically stirred at room temperature for 30 min; then, 1 g of Ti3AlC2 was added to the above mixture and stirred at 38 °C for 24 h. The reaction mixture was added with 25 mL of deionized water and centrifuged at 3500 rpm for purification. The centrifugation purification step was repeated several times until the pH value of the supernatant was close to 7. The precipitate obtained after centrifugal purification was added with deionized water and ultrasonically treated under Ar gas bubbling conditions for 30 min; finally, the upper layer solution after ultrasonic treatment was centrifuged at 3500 rpm for 30 min, the upper layer solution was collected and freeze-dried to obtain MXene nanosheets; (2) Synthesis of W by solvent thermal method 18 O 49 Nanowires: First, 50 mg of WCl6 was dissolved in 34 mL of anhydrous ethanol and stirred for 30 min to obtain a transparent light yellow solution. Subsequently, the resulting solution was transferred to a 50 mL polytetrafluoroethylene-lined autoclave, sealed, and heated at 473 K for 12 h. After the device was cooled to room temperature, the product was separated by centrifugation and washed four times with anhydrous ethanol. Finally, the product was dried in a vacuum oven at 300 K for 10 h to obtain W 18 O 49 nanowires; (3) Disperse the MXene nanosheets evenly in water and then add W 18 O 49 Nanowires, stirred evenly, and dried to obtain MXene@W 18 O 49 Hybrid; wherein, by mass ratio, W 18 O 49 ∶Mxene=3∶1; (4) 21 mg MXene@W 18 O 49 The hybrid was dispersed in 4 mL of acetone to obtain MXene@W 18 O 49 / acetone dispersion; (5) First, 20 g of polytetrahydrofuran was placed in a reaction vessel and stirred at 120 ° C for 1 h; secondly, the temperature of the obtained system was lowered to 70 ° C, and after the temperature stabilized, 11.9 mL of diisocyanate, 50 μL of dibutyltin dilaurate and 5 mL of ethyl acetate were added to the above reaction vessel in sequence, and the prepolymerization reaction was carried out under stirring for 2 h; then, the temperature of the obtained system was lowered to 40 ° C, and after the temperature stabilized, 3.8 mL of 2-hydroxyethyl disulfide was added to the reaction vessel, and the chain extension reaction was carried out under stirring for 30 min; after the chain extension reaction was completed, the system temperature was maintained unchanged, and the MXene@W obtained in step (4) was added. 18 O 49 / acetone dispersion is added dropwise into the reaction vessel and stirred evenly; step (5) is carried out under protective atmosphere throughout; (6) The reactant obtained in step (5) was poured into a Teflon mold and cured in an oven at 65°C for 24 hours. The light-driven MXene@W films of different thicknesses were obtained by a laminating machine. 18 O 49 -PU self-healing transparent film, marked as PUMW2.
[0028] Example 2
[0029] The difference from Example 1 is that in step (3), W 18 O 49 ∶MXene =1:1; other parameters are the same as Example 1.
[0030] The light-driven MXene@W obtained in this example 18 O 49 -PU self-healing transparent film, marked as PUMW3.
[0031] Example 3
[0032] The difference from Example 1 is that in step (3), W 18 O 49 ∶MXene =1:3; other parameters are the same as in Example 1.
[0033] The light-driven MXene@W obtained in this example 18 O 49 -PU self-healing transparent film, marked as PUMW4.
[0034] Comparative Example 1 - No addition of Mxene and W 18 O 49 (1) First, 20 g of polytetrahydrofuran was placed in a reaction vessel and stirred at 120 ° C for 1 hour; secondly, the temperature of the obtained system was lowered to 70 ° C, and after the temperature stabilized, 11.9 mL of diisocyanate, 50 μL of dibutyltin dilaurate and 5 mL of ethyl acetate were added to the above reaction vessel in sequence, and the prepolymerization reaction was carried out under stirring for 2 hours; then, the temperature of the obtained system was lowered to 40 ° C, and after the temperature stabilized, 3.8 mL of 2-hydroxyethyl disulfide was added to the reaction vessel, and the chain extension reaction was carried out under stirring for 30 minutes; step (1) was carried out under protective atmosphere throughout; (2) The reactant obtained in step (1) was poured into a Teflon mold and cured in an oven at 65°C for 24 hours. Pure PU films of different thicknesses were obtained by a laminator and marked as PUMW0.
[0035] Comparative Example 2: No Mxene added, only W added 18 O 49 (1) Synthesis of W by solvent thermal method 18 O 49Nanowires: First, 50 mg of WCl6 was dissolved in 34 mL of anhydrous ethanol and stirred for 30 min to obtain a transparent light yellow solution. Subsequently, the resulting solution was transferred to a 50 mL polytetrafluoroethylene-lined autoclave, sealed, and heated at 473 K for 12 h. After the device was cooled to room temperature, the product was separated by centrifugation and washed four times with anhydrous ethanol. Finally, the product was dried in a vacuum oven at 300 K for 10 h to obtain W 18 O 49 nanowires; (2) 21mg W 18 O 49 The nanowires were dispersed in 4 mL of acetone to prepare W 18 O 49 / acetone dispersion; (3) First, 20 g of polytetrahydrofuran was placed in a reaction vessel and stirred at 120 ° C for 1 h; secondly, the temperature of the obtained system was lowered to 70 ° C, and after the temperature stabilized, 11.9 mL of diisocyanate, 50 μL of dibutyltin dilaurate and 5 mL of ethyl acetate were added to the above reaction vessel in sequence, and the prepolymerization reaction was carried out under stirring for 2 h; then, the temperature of the obtained system was lowered to 40 ° C, and after the temperature stabilized, 3.8 mL of 2-hydroxyethyl disulfide was added to the reaction vessel, and the chain extension reaction was carried out under stirring for 30 min; after the chain extension reaction was completed, the system temperature was maintained unchanged, and the MXene / acetone dispersion obtained in step (2) was added dropwise to the reaction vessel, and the stirring was continued; step (3) was carried out under protective atmosphere throughout the process; (4) Pour the reactant obtained in step (3) into a Teflon mold, solidify it in an oven at 65°C for 24 hours, and obtain W films of different thicknesses using a laminating machine. 18 O 49 -PU film, marked as PUMW1.
[0036] Comparative Example 3 - No W added 18 O 49 , only add Mxene (1) MXene nanosheets were synthesized on Ti3AlC2 precursor using a selective etching process: First, 1 g of LiF was dissolved in 20 mL of concentrated HCl solution (36 wt%) and transferred to a 50 mL polytetrafluoroethylene liner and magnetically stirred at room temperature for 30 min; then, 1 g of Ti3AlC2 was added to the above mixture and stirred at 38 °C for 24 h. The reaction mixture was added with 25 mL of deionized water and centrifuged at 3500 rpm for purification. The centrifugation purification step was repeated several times until the pH value of the supernatant was close to 7. The precipitate obtained after centrifugal purification was added with deionized water and ultrasonically treated under Ar gas bubbling conditions for 30 min; finally, the upper layer solution after ultrasonic treatment was centrifuged at 3500 rpm for 30 min, the upper layer solution was collected and freeze-dried to obtain MXene nanosheets; (2) Disperse 21 mg of MXene nanosheets in 4 mL of acetone to prepare a MXene nanosheet / acetone dispersion; (3) First, 20 g of polytetrahydrofuran was placed in a reaction vessel and stirred at 120 ° C for 1 h; secondly, the temperature of the obtained system was lowered to 70 ° C, and after the temperature stabilized, 11.9 mL of diisocyanate, 50 μL of dibutyltin dilaurate and 5 mL of ethyl acetate were added to the above reaction vessel in sequence, and the prepolymerization reaction was carried out under stirring for 2 h; then, the temperature of the obtained system was lowered to 40 ° C, and after the temperature stabilized, 3.8 mL of 2-hydroxyethyl disulfide was added to the reaction vessel, and the chain extension reaction was carried out under stirring for 30 min; after the chain extension reaction was completed, the system temperature was maintained unchanged, and the MXene / acetone dispersion obtained in step (2) was added dropwise to the reaction vessel, and the stirring was continued; step (5) was carried out under protective atmosphere throughout the process; (4) The reactant obtained in step (3) was poured into a Teflon mold and cured in an oven at 65°C for 24 h. MXene-PU films of different thicknesses were obtained by a laminator and were labeled as PUMW5.
[0037] Comparative Example 4 The difference from Comparative Example 3 is that in step (2), the amount of MXene nanosheets is changed to 15.75 mg; the rest is the same as Comparative Example 3.
[0038] In this comparative example 4, a Mxene-PU film was finally prepared and marked as PUM3.
[0039] Product structure characterization Figure 1 The Mxene nanosheets prepared in Example 3, W 18 O 49 Nanowires, MXene@W 18 O 49 SEM image of the hybrid. Figure 1 It can be seen that: ultra-fine W18 O 49 The nanowires are evenly distributed on the surface of smooth two-dimensional MXene nanosheets, indicating that MXene@W 18 O 49 The hybrids were successfully prepared.
[0040] Figure 2 MXene nanosheets and W prepared in Example 3 18 O 49 The UV-visible-near infrared absorption spectra of nanowires in aqueous solution were measured using a UV-3600i Plus spectrophotometer. Figure 2 It can be seen that MXene nanosheets and W 18 O 49 Nanowires exhibit excellent light absorption energy in the near-infrared band, and existing research has shown that the absorption characteristics of the near-infrared band have a significant impact on the photothermal conversion efficiency of nanomaterials.
[0041] Product performance testing (1) Light transmittance test Figure 3 Figure 3 shows the visible light transmittance of PUMW4 films prepared according to the present invention at different thicknesses. The results show that within the wavelength range of 400-800 nm, the transmittance decreases with increasing PUMW4 film thickness. At a thickness of 0.2 mm, the visible light transmittance of the PUMW4 film remains above 79%, demonstrating excellent transmittance and high transparency.
[0042] (2) Mechanical tensile properties test The test instrument is an electric tensile testing machine. The test method is to perform mechanical tensile testing on dumbbell-shaped samples with a deformation rate of 100 mm min -1 The dumbbell-shaped samples were prepared using a CP-25 manual punching machine combined with a type 4 dumbbell-shaped specimen cutter (GB / T528-2009, Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber).
[0043] Figure 4 The tensile stress-strain performance diagram (a) and columnar statistical results (b) of the 1mm thick PUMW0-PUMW5 film prepared by the present invention. Figure 4 It can be seen that: compared with pure PU (PUMW0), pure MXene (PUMW5) and pure W 18 O 49 (PUMW1),MXene@W 18 O 49The addition of hybrids makes the composite film have better mechanical properties. The tensile strength of PUMW2 is 32.2MPa, the elongation at break is 1102%, and the toughness is 116.5MJ m -3 This phenomenon can be attributed to the fact that the tension generated by strain is transferred from the polyurethane matrix to the MXene sheet. The unique two-dimensional layered structure of MXene enables it to effectively withstand strain and absorb the energy generated by the applied pressure, thereby generating a strong interfacial interaction with PU. This interaction can act as a barrier to prevent the formation and expansion of cracks. However, with the further increase of MXene content, the mechanical properties of the composite film gradually decrease. This is because excessive MXene will introduce more defects, which will have an adverse effect on the overall dispersion and lead to a decrease in mechanical properties.
[0044] (2) Photothermal conversion performance test Figure 5 Photothermal conversion performance: (a) PUMW0-PUMW5 film with a thickness of 1 mm prepared by the present invention at 0.45 W cm -2 (a) is the temperature rise curve of the sample under the irradiation of NIR light (λ=808nm) of different intensities, and (b) is the relationship curve between the temperature rise (ΔT) and the irradiation power density of the PUMW4 and PUM3 films with a thickness of 1mm prepared by the present invention after irradiation of NIR light (λ=808nm) of different intensities for 5 minutes. Figure 5 aIt can be seen that MXene@W 18 O 49 The addition of hybrids makes MXene@W 18 O 49 -PU composite film has good light-to-heat conversion performance, especially PUMW4 can reach the highest stable temperature of 102℃ after 5min of NIR light irradiation, which is better than that of W-only composite film. 18 O 49 The maximum stable temperature of PUMW1 and PUMW0 without any filler is high; Figure 5 b It can be seen that: under the same MXene content and the same irradiation power density, due to the 18 O 49 The synergistic effect between MXene@W 18 O 49 The hybrid PUMW4 film has a higher temperature than the PUM3 film containing pure MXene. This is because: the photothermal effect of MXene is stronger and dominant, and the hybrid MXene@W 18 O 49 The photothermal filler is combined with W 18 O 49The plasma effect and the excellent photothermal properties, high thermal conductivity and unique structural advantages of MXene itself, as well as the synergistic effect between the two, show extremely outstanding photothermal conversion performance.
[0045] The volunteer put on a blue nitrile glove on his left arm, and covered the back of his hand with the PUMW4 film with a thickness of 200 μm prepared by the present invention, while leaving other areas uncovered. The volunteer clenched his hand into a fist, and the entire arm was exposed to sunlight. Figure 6 The photo of the 200μm thick PUMW4 film prepared by the present invention coated on a volunteer's hand (left) and the infrared thermal imaging after 1 minute of sunlight exposure (right). The dotted box is the coated area, and the test instrument is a handheld infrared thermal imager. Figure 6 It can be seen that due to the good light-to-heat conversion properties of the PUMW4 film, after 1 minute of irradiation, the temperature in the dotted frame covered with the film is higher than the temperature at the arm outside the frame that is not covered with the film, indicating that MXene@W 18 O 49 -PU composite films have the potential to be used as flexible thermal management devices in practical applications.
[0046] (3) Cooling performance test Build a house model: enclose six pieces of plexiglass to form a cube, and then cover the front, back, left, right, and bottom outer surfaces of the cube with white polypropylene foam of corresponding sizes (this can minimize the influence of external heat convection and heat radiation from the surrounding environment). Leave a part of the top surface of the cube uncovered with white polypropylene foam (this uncovered area serves as a simulated skylight), while covering the other areas with white polypropylene foam. A temperature sensor is fixed on the inner wall of the simulated skylight.
[0047] Test method: Two identical house models were built according to the above construction process. One model served as a blank control group (the simulated skylight position was not covered with PUMW4 film), and the other model served as an experimental group (the organic glass at the simulated skylight position was covered with the 1-mm-thick PUMW4 film prepared by the present invention). The two house models were placed in a real outdoor environment, and a temperature sensor recorded the indoor temperature.
[0048] Figure 7 The cooling performance simulation results are as follows: (a) is a photo of the actual outdoor cooling performance test of the experimental group and the blank control group, and (b) is a comparison chart of the cooling performance of the experimental group and the blank control group. Figure 7 It can be seen that MXene@W 18 O 49-PU composite film has a strong photothermal effect. Compared with the blank control without this film, the internal temperature of the house model covered with the film is reduced by 10℃, which can effectively cool the indoor temperature. This is because: in the experimental group, the film will first reflect some light, preventing light from entering the interior. Secondly, after the film converts light into heat, part of it is converted into internal 2S bond vibration and dissipated, and part of the heat is lost through heat conduction from the external air. Compared with the blank control group, the energy transmitted to the interior of the experimental group is relatively less, resulting in a lower degree of indoor temperature increase in the experimental group compared to the blank control group. The experimental results show that: MXene@W 18 O 49 -PU composite films are expected to find applications in skyscraper window coatings and indoor thermal management of large buildings.
[0049] (IV) Light-driven self-healing and capability testing Making scratches: A scratch was made on the PUMW4 film with a thickness of 1 mm prepared in the present invention using a sharp blade.
[0050] The scratched PUMW4 film was heated at 0.9 W cm -2 The self-healing process of the scratched film was recorded using a polarizing microscope under near-infrared light. Figure 8 This is a diagram showing the light-driven self-healing effect of a 1mm thick PUMW4 film with scratches prepared by the present invention (the scale bar is 100μm). Figure 8 It can be seen that MXene@W 18 O 49 -PU composite film exhibits fast and efficient light-driven self-healing ability. As the irradiation time increases, the scratch depth gradually decreases and completely disappears after 2 minutes of irradiation.
[0051] In order to provide a quantitative characterization of the self-healing performance, strain-stress experiments were conducted to evaluate the mechanical self-healing properties of the prepared films. The self-healing efficiency is defined as the ratio of the mechanical properties of the film after different repair times to the corresponding mechanical properties of the original intact film. The test instrument is an electric tensile testing machine. The test method is to perform tensile tests on the dumbbell-shaped sample in the original intact state, the scratch initial state, the self-healing 3min, and the self-healing 5min, respectively. The deformation rate is 100mm / min. -1 The dumbbell-shaped sample was prepared using a CP-25 manual punching machine combined with a type 4 dumbbell-shaped specimen cutter (GB / T 528-2009, Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber). The PUMW4 film with a thickness of 1 mm prepared in the present invention was scratched in the narrow part of the dumbbell-shaped sample with a scratch width of 150 μm. Figure 9The mechanical self-healing performance results are as follows: (a) The original intact state, the scratch initial state, and the mechanical self-healing performance of the 1 mm thick PUMW4 film prepared by the present invention at 0.9 W cm -2 Stress-strain curves after 3 min and 5 min of near-infrared light irradiation, (b) is a histogram of the mechanical self-healing efficiency of the PUMW4 film with a thickness of 1 mm prepared by the present invention. Figure 9 It can be seen that MXene@W 18 O 49 -PU composite film has excellent mechanical self-healing properties. When the irradiation time is 5 minutes, it can achieve a significant self-healing efficiency of up to 95% toughness, 97% elongation at break, and 96% tensile strength. It also has high mechanical properties, with a toughness of 96.8MJ m -3 , tensile strength is 29.4 Mpa, and elongation at break is 1009.3%.
Claims
1. A light-driven MXene@W 18 O 49 -PU self-healing transparent film, characterized by: The film includes a thermoplastic PU matrix and MXene@W embedded therein. 18 O 49 Hybrid, MXene@W 18 O 49 The mass percentage of the hybrid in the thermoplastic PU matrix is 0.02~1%.
2. A light-driven MXene@W as claimed in claim 1 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: Here are the steps: (1) Disperse MXene nanosheets evenly in water, then add W 18 O 49 Nanowires, stirred evenly, and dried to obtain MXene@W 18 O 49 Hybrid; wherein, by mass ratio, W 18 O 49 ∶MXene=(1~3)∶(1~3) (2) MXene@W 18 O 49 The hybrid was dispersed in acetone to obtain MXene@W 18 O 49 / acetone dispersion; wherein, based on mass volume ratio, MXene@W 18 O 49 Hybrid: acetone = (7~35) mg: (3~5) mL; (3) Thermoplastic PU was prepared by a two-step method under a protective atmosphere: the first step was prepolymerization, and the second step was chain extension reaction; after the chain extension reaction, MXene@W was added. 18 O 49 / acetone dispersion, stir evenly; (4) Pour the reactants obtained in step (3) into the mold and solidify to obtain light-driven MXene@W 18 O 49 -PU self-healing transparent film.
3. The light-driven MXene@W as claimed in claim 2 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: In step (3), a prepolymerization reaction is carried out using polyol, isocyanate, catalyst and solvent as raw materials, and then a chain extender is added to carry out a chain extension reaction.
4. The light-driven MXene@W as claimed in claim 3 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: The specific process of step (3) is: (3.1) Place the polyol in a reaction vessel and stir at 100-120°C for 0.5-3h; (3.2) Lower the temperature of the system obtained in step (3.1) to 60-80°C. After the temperature stabilizes, add isocyanate, catalyst, and solvent to the above reaction vessel in sequence and perform prepolymerization reaction under stirring for 1-3 hours. (3.3) Lower the temperature of the system obtained in step (3.2) to 35-50°C. After the temperature stabilizes, add the chain extender to the above reaction vessel and carry out the chain extension reaction for 10-60 minutes under stirring conditions. (3.4) After the chain extension reaction is completed, the system temperature is maintained constant and MXene@W 18 O 49 / acetone dispersion was added dropwise into the above reaction vessel and stirred until uniform; Step (3) is carried out entirely under protective atmosphere.
5. The light-driven MXene@W according to claim 3 or 4 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: The polyol is polytetrahydrofuran, the isocyanate is diisocyanate, the catalyst is dibutyltin dilaurate, the solvent is ethyl acetate, and the chain extender is 2-hydroxyethyl disulfide.
6. The light-driven MXene@W as claimed in claim 5 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: Calculated by mass-to-volume ratio, polytetrahydrofuran: diisocyanate: dibutyltin dilaurate: ethyl acetate: 2-hydroxyethyl disulfide = (16-24) g: (11.2-12.6) mL: (45-60) μL: (4-6) mL: (3-4.5) mL.
7. The light-driven MXene@W as claimed in claim 2 18 O 49 -A method for preparing a PU self-healing transparent film, characterized in that: The curing temperature is 50~80℃ and the curing time is 20~30h.
8. A light-driven MXene@W as claimed in claim 1 18 O 49 -Application of PU self-healing transparent films in flexible wearable electronic devices, indoor thermal management of large buildings, or anti-counterfeiting measures.