Intelligent light-following evaporator based on MXene-based composite non-woven fabric and film integration and preparation method of intelligent light-following evaporator

Abstract

The invention discloses an intelligent light-following evaporator based on MXene-based composite non-woven fabric and film integration and a preparation method thereof.The intelligent light-following evaporator comprises a PANI / GO / MXene composite non-woven fabric evaporator located on the upper portion and a flexible driver located on the lower portion, the size of the flexible driver is matched with that of the PANI / GO / MXene composite non-woven fabric evaporator, the flexible driver and the PANI / GO / MXene composite non-woven fabric evaporator are fixed through waterproof glue, and the flexible driver and the PANI / GO / MXene composite non-woven fabric evaporator are fixed through waterproof glue. The driver drives the evaporator to move towards the light under single-side light and can provide a supporting effect. By utilizing the advantages of high evaporation rate of the non-woven fabric evaporator and durability and rapid driving of the thin film driver, the intelligent evaporator with sunflower characteristics is realized, the evaporator can perform corresponding structure or orientation change according to the change of the illumination angle, the utilization efficiency of sunlight is maximized, and the energy consumption is reduced. The method is of great significance to future novel evaporation equipment and waste water recycling.

Description

Technical Field

[0001] The present invention belongs to the field of materials science, and relates to a light-tracking evaporator, in particular to an intelligent light-tracking evaporator based on MXene-based composite non-woven fabric and film integration and a preparation method thereof. Background Technique

[0002] Water evaporation is an important physical phenomenon in nature and has an important impact on the global water cycle, climate regulation and ecological balance. With the increasing demand for sustainable development, people pay more and more attention to the regulation and utilization of the evaporation process, especially in the context of the shortage of fresh water resources and the development of seawater desalination technology. Studying the water evaporation mechanism helps to improve energy utilization efficiency and develop efficient evaporation materials, providing technical support for agricultural irrigation, sewage treatment and solar-driven seawater desalination. Common evaporators are mainly made of metals and metal-based composite materials, polymer materials, carbon-based materials, and MXene into forms such as hydrogels, aerogels, and films. The evaporation efficiency has been greatly improved from the earliest film evaporators to the subsequent 3D bulk evaporators. At present, researchers have invested a lot of research in the form of evaporators, and in order to better utilize solar energy, the evaporators are made into 3D forms such as arched and cylindrical. However, during the day, the azimuth angle of sunlight changes continuously with time, and the 3D evaporator still cannot increase the evaporation efficiency to the maximum. Summary of the Invention

[0003] In order to efficiently utilize solar energy for water resource purification, the present invention provides an intelligent light-tracking evaporator based on MXene-based composite non-woven fabric and film integration and a preparation method thereof. The present invention integrates an evaporator with a driver. The flexible driver is dimensionally matched with the PANI / GO / MXene composite non-woven fabric evaporator and is fixed by a waterproof glue. The driver drives the evaporator to move towards the light under unilateral light and can provide a supporting effect, realizing high-precision light tracking of the evaporator to improve its solar energy utilization rate. The present invention utilizes the advantages of the high evaporation rate of the non-woven fabric evaporator and the durability and fast driving of the film driver to realize a sunflower-like intelligent evaporator, which can change its corresponding structure or orientation according to the change of the illumination angle, maximizing the utilization efficiency of sunlight, and is of great significance for future new evaporation equipment and wastewater reuse.

[0004] The object of the present invention is achieved by the following technical solutions:

[0005] An intelligent light-tracking evaporator based on the integration of MXene-based composite non-woven fabric and film, comprising a PANI / GO / MXene composite non-woven fabric evaporator located above and a flexible driver located below. The flexible driver matches the size of the PANI / GO / MXene composite non-woven fabric evaporator and is fixed by waterproof glue. The driver drives the evaporator to move towards the light under unilateral light and can provide a supporting role. Among them:

[0006] The PANI / GO / MXene composite non-woven fabric evaporator is made of surface-creased fibers made of dry PANI / GO / MXene mixture. The surface-creased fibers are formed by wet spinning and naturally shrink in the air to form creases. The coagulation bath is an aqueous solution containing HCl and CH 3 COOH, and an APS solution is added dropwise during the spinning process to promote the in-situ polymerization of aniline;

[0007] The light absorption rate of the PANI / GO / MXene composite non-woven fabric evaporator can reach more than 95%;

[0008] The flexible driver is made by attaching an MXene thin film coating to an LDPE film by ink writing. The thickness of the MXene thin film coating is 25 - 35m, and the thickness of the LDPE film is 35 - 50μm;

[0009] The MXene thin film coating is formed by concentrating a pure MXene aqueous solution;

[0010] When the intelligent light-tracking evaporator is exposed to light, the upper evaporator rapidly heats up within a short time of illumination, heating the moisture inside the film to promote evaporation; while the lower flexible driver provides support for the evaporator and bends towards the light source side when receiving unilateral light irradiation, driving the evaporator to bend towards the light and thus improving the evaporation efficiency; when the illumination angle of the surrounding environment shifts, the intelligent light-tracking evaporator deforms and adjusts to the light-facing state;

[0011] The light is the light generated by a xenon lamp.

[0012] A preparation method of the above-mentioned intelligent light-tracking evaporator based on the integration of MXene-based composite non-woven fabric and film, comprising the following steps:

[0013] Step 1. Preparation of MXene nanosheets:

[0014] Step 1-1. Use LiF and HCl to etch the MAX phase to remove the A layer and wash it to neutral to obtain an MXene precursor. Among them: the etching time of the MAX phase is 20 - 30h;

[0015] Steps 1-2: Disperse the MXene precursor in water, and after ultrasonic treatment in an ice bath, centrifuge twice to exfoliate monolayer MXene nanosheets. Among them: the rotation speed of the first centrifugation is 3000-5000 r / min, and the time is 10-30 min; the rotation speed of the second centrifugation is 9000-11000 r / min, and the time is 10-30 min;

[0016] Step 2: Preparation of MXene dispersion:

[0017] Step 2-1: Obtain MXene aqueous dispersion by the MILD method;

[0018] Step 2-2: Treat the MXene aqueous dispersion prepared in Step 1 with TBAOH solution to exchange surface groups and centrifuge to separate, and collect the MXene precipitate. Among them: TBAOH:MXene = 5:1 (molar ratio);

[0019] Step 2-3: Redisperse the MXene precipitate in DMAc to obtain an MXene dispersion with a concentration of 20-40 mg / ml;

[0020] Step 3: Preparation of GO dispersion:

[0021] Disperse GO in DMAc to obtain a GO dispersion with a concentration of 10-20 mg / ml;

[0022] Step 4: Preparation of PANI / GO / MXene composite nonwoven fabric evaporator:

[0023] Step 4-1: Take 5-10 ml of the GO dispersion prepared in Step 3 as the substrate, add ANI and MXene to obtain a MXene / GO / ANI mixed spinning slurry. Among them: the total mass of ANI and MXene is 210 mg, and the mass ratio of MXene to ANI is 1-8:1;

[0024] Step 4-2: Inject the MXene / GO / ANI mixed spinning slurry into a coagulation bath containing HCl and CH 3 COOH, and dropwise add APS solution during the spinning process to promote in-situ polymerization of aniline. The molar ratio of APS to ANI is 1:1;

[0025] Step 4-3: Let the spun composite fibers stand at 0 °C to promote in-situ polymerization. Among them: the time of in-situ polymerization is 20-30 hours;

[0026] Step 4-4: Collect the fibers by vacuum filtration and dry them in air at room temperature to form a PANI / GO / MXene composite nonwoven fabric evaporator;

[0027] Step 5: Preparation of flexible actuator:

[0028] Step 5.1: Purify the MXene aqueous dispersion prepared in Step 1 and then redisperse it to prepare printing ink. Use a microelectronic printer to perform pneumatic extrusion printing on the LDPE film at a gas pressure of 5 - 20 kPa, depositing the ink layer by layer. Among them: the concentration of the ink is 30 - 40%, the distance between the printing nozzle and the substrate is 0.07 mm, and the moving speed is 2 - 10 mm / s;

[0029] Step 5.2: Dry the printed double-layer film, and then peel and trim it to obtain the required flexible actuator. Among them: the drying time of the double-layer film is 1 - 3 hours.

[0030] The working principle of the present invention is based on photothermal conversion and adaptive phototropic regulation, aiming to optimize solar absorption and improve water evaporation efficiency. The device uses high-efficiency photothermal materials: MXene, GO, PANI, to absorb sunlight and convert it into heat energy to heat the water surface and promote evaporation. At the same time, the device integrates a flexible deflection structure that can adaptively adjust the angle to always face the direction with the strongest light, thereby enhancing the photothermal conversion efficiency. This deflection structure is manufactured by high-precision direct ink writing (DIW). Due to the high coefficient of thermal expansion of the LDPE film, the thermal-driven bending effect caused by the mismatch of thermal expansion of the double-layer material can respond to the change of the solar angle and quickly adjust the position within different azimuth and zenith angle ranges to ensure the maximization of photothermal absorption. Verified by finite element simulation, the device can dynamically follow the sun, reduce the energy loss caused by angle deviation, and thus maintain stable evaporation performance under different lighting conditions.

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

[0032] 1. The present invention uses MXene, GO, and PANI as raw materials for the non-woven fabric evaporator, having the advantages of high photothermal conversion efficiency, porous structure, and hierarchical pore channels.

[0033] 2. The present invention adopts a flexible deflection structure that can adaptively adjust the angle to ensure that the evaporator always faces the sun, improving the photothermal absorption efficiency and overcoming the limitations of traditional fixed-angle evaporators. At the same time, based on the thermal-driven bending effect, no external sensors or electric systems are required to achieve passive adaptive regulation without additional energy, effectively improving the solar energy utilization rate and evaporation efficiency, and breaking through the energy consumption and complexity limitations of existing optical tracking technologies.

[0034] 3. The present invention uses a composite photothermal layer of MXene, GO, and PANI. Compared with traditional single photothermal materials, it can absorb a wider spectrum of sunlight and achieve more efficient photothermal conversion. At the same time, an adjustable structure is innovatively introduced, enabling the evaporator to maintain high-efficiency evaporation at different solar angles, overcoming the problem of a significant decrease in the evaporation rate of traditional evaporators at the zenith angle, thereby increasing the evaporation amount and overall energy utilization rate, and achieving all-weather high-efficiency solar evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the surface scanning electron microscope photograph of the PGM evaporator obtained in Step 3 of Example 1;

[0036] Figure 2 is the light absorption rate data graph of the PGM evaporator obtained in Step 3 of Example 1;

[0037] Figure 3 is the schematic diagram of the evaporation efficiency of the PGM evaporator obtained in Step 3 of Examples 1-4;

[0038] Figure 4 is the cross-sectional scanning photograph of the light-responsive actuator obtained in Step 4 of Example 1;

[0039] Figure 5 is the light-tracking data graph of the intelligent light-tracking evaporator obtained in Step 4 of Example 1 under incident light irradiation at different zenith angles. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered within the protection scope of the present invention.

[0041] Example 1

[0042] This example provides a preparation method of an intelligent light-tracking evaporator based on MXene-based composite non-woven fabric and film integration. The method includes the following steps:

[0043] Step 1: Preparation of MXene nanosheets:

[0044] Use LiF and HCl to etch the MAX phase to remove the A layer and wash it to neutral to obtain a MXene precursor. Among them, the etching time of the MAX phase is 24 h; disperse the MXene precursor in water, and exfoliate the single-layer MXene nanosheets by ice-bath ultrasonic treatment followed by two centrifugations. Among them, the first centrifugation speed is 4000 r / min and the time is 20 min; the second centrifugation speed is 10000 r / min and the time is 20 min.

[0045] Step 2: Preparation of MXene organic dispersion:

[0046] For surface group exchange, the MXene aqueous dispersion from Step 1 is treated with TBAOH solution and centrifuged to collect the MXene precipitate; the MXene precipitate is redispersed in DMAc to obtain the MXene dispersion, where: TBAOH:MXene = 5:1 (molar ratio), and the concentration of the MXene dispersion is 30 mg / ml.

[0047] Step 3: Preparation of GO organic dispersion:

[0048] Disperse the GO dispersion in DMAc and adjust the concentration to 15 mg / ml.

[0049] Step 4: Preparation of PGM evaporator:

[0050] First, using 6 ml of a high-concentration (15 mg / ml) GO dispersion as the substrate, add ANI and MXene (total mass of 210 mg, mass ratio of MXene to ANI is 1:1) to obtain the PGM1 spinning slurry; then, after stirring the above mixture for 15 minutes, extrude it through a syringe into a coagulation bath containing HCl and CH 3 COOH, and add APS solution dropwise during the spinning process to promote the in-situ polymerization of aniline, with the molar ratio of APS to ANI being 1:1; finally, place the spun composite fiber at 0 °C for 24 hours, filter it under vacuum and dry it at room temperature to obtain the PANI / GO / MXene composite nonwoven evaporation film.

[0051] Step 5: Preparation of bilayer structure light-responsive actuator (PEM flexible actuator):

[0052] First, centrifuge the MXene aqueous dispersion prepared in Step 1 at 10000 rpm for 60 minutes, collect the precipitate, disperse it in deionized water and stir at high speed to prepare a 40% high-concentration ink; then, place the ink in a syringe equipped with a 260 mm needle and print it on the LDPE film substrate under a pressure of 12 kPa, controlling the distance between the nozzle and the substrate to be 0.07 mm and the nozzle moving speed to be 4 mm / s, and print 5 layers layer by layer according to the pre-designed pattern; finally, dry it at room temperature for 2 hours and then peel it off to form a bilayer structure film, and after trimming, the required PEM flexible actuator is obtained.

[0053] Step 6: Preparation of intelligent light-tracking evaporator:

[0054] Fix the flexible actuator prepared in Step 5 and the PANI / GO / MXene composite nonwoven evaporator prepared in Step 4 together with waterproof glue to obtain the intelligent light-tracking evaporator based on the integration of MXene-based composite nonwoven fabric and film.

[0055] Example 2

[0056] This example provides a preparation method of an intelligent light-tracking evaporator based on MXene-based composite non-woven fabric and film integration. The method includes the following steps:

[0057] Step 1: Preparation of MXene nanosheets:

[0058] Use LiF and HCl to etch the MAX phase to remove the A layer, and wash it to neutral to obtain a MXene precursor. Among them, the etching time of the MAX phase is 24 h; disperse the MXene precursor in water, and centrifuge and exfoliate the single-layer MXene nanosheets twice through ice bath ultrasonic treatment. Among them, the first centrifugation speed is 4000 r / min and the time is 20 min; the second centrifugation speed is 10000 r / min and the time is 20 min.

[0059] Step 2: Preparation of MXene organic dispersion:

[0060] In order to carry out surface group exchange, treat the MXene aqueous dispersion in step 1 with a TBAOH solution and centrifuge to separate, and collect the MXene precipitate; redisperse the MXene precipitate in DMAc to obtain a MXene dispersion. Among them, TBAOH:MXene = 5:1 (molar ratio), and the concentration of the MXene dispersion is 30 mg / ml.

[0061] Step 3: Preparation of GO dispersion:

[0062] Disperse the GO dispersion in TBAOH and adjust the concentration to 15 mg / ml.

[0063] Step 4: Preparation of PGM evaporator:

[0064] First, use 6 ml of high-concentration (15 mg / ml) GO dispersion as the substrate, add ANI and MXene (total mass is 210 mg, and the mass ratio of MXene to ANI is 2:1) to obtain PGM2 spinning slurry; then, after stirring the above mixture for 15 minutes, extrude it through a syringe into a coagulation bath containing HCl and CH 3 COOH, and dropwise add an APS solution during the spinning process to promote the in-situ polymerization of aniline. The molar ratio of APS to ANI is 1:1; finally, place the spun composite fiber at 0 °C for 24 hours, vacuum filter and dry at room temperature to obtain a PANI / GO / MXene composite non-woven evaporation film.

[0065] Step 5: Preparation of a double-layer structure light-responsive actuator (PEM flexible driving platform):

[0066] First, centrifuge the MXene aqueous dispersion prepared in Step 1 at 1000 rpm for 60 minutes. After collecting the precipitate, disperse it in deionized water and stir at high speed to prepare a high-concentration ink with a concentration of 30%. Then, place the ink in a syringe equipped with a 260-mm needle and print it on the LDPE film substrate under a gas pressure of 5 kPa. Control the distance between the nozzle and the substrate to be 0.07 mm, the moving speed of the nozzle to be 4 mm / s, and print 5 layers layer by layer according to the pre-designed pattern. Finally, after drying at room temperature for 2 hours, peel it off to form a double-layer structure film, and after trimming, the required PEM flexible actuator is obtained.

[0067] Step 6: Preparation of the intelligent light-tracking evaporator:

[0068] Fix the flexible actuator prepared in Step 5 and the PANI / GO / MXene composite nonwoven fabric evaporator prepared in Step 4 together with waterproof glue to obtain the intelligent light-tracking evaporator based on the integration of MXene-based composite nonwoven fabric and film.

[0069] Example 3

[0070] This example provides a preparation method of an intelligent light-tracking evaporator based on the integration of MXene-based composite nonwoven fabric and film. The method includes the following steps:

[0071] Step 1: Preparation of MXene nanosheets

[0072] Use LiF and HCl to etch the MAX phase to remove the A layer and wash it to neutrality to obtain the MXene precursor. Among them, the etching time of the MAX phase is 24 h; disperse the MXene precursor in water, and after ice-bath ultrasonic treatment, centrifuge and peel it twice to obtain single-layer MXene nanosheets. Among them, the first centrifugation speed is 4000 r / min and the time is 20 min; the second centrifugation speed is 10000 r / min and the time is 20 min.

[0073] Step 2: Preparation of MXene organic dispersion:

[0074] In order to carry out surface group exchange, treat the MXene aqueous dispersion in Step 1 with TBAOH solution and centrifuge and separate it to collect the MXene precipitate; redisperse the MXene precipitate in DMAc to obtain the MXene dispersion. Among them, TBAOH:MXene = 5:1 (molar ratio), and the concentration of the MXene dispersion is 30 mg / ml.

[0075] Step 3: Preparation of GO organic dispersion:

[0076] Disperse the GO dispersion in DMAc and adjust the concentration to 15 mg / ml.

[0077] Step 4. Preparation of the PGM evaporator:

[0078] First, using 6 ml of a high-concentration (15 mg / ml) GO dispersion as the substrate, add the ANI and MXene (total mass of 210 mg, mass ratio of MXene to ANI is 4:1) PGM3 spinning slurry; then, after stirring the above mixture for 15 minutes, extrude it through a syringe into a coagulation bath containing HCl and CH 3 COOH, and dropwise add an APS solution during the spinning process to promote the in-situ polymerization of aniline, with the molar ratio of APS to ANI being 1:1; finally, place the spun composite fibers at 0 °C for 24 hours, vacuum filter and dry at room temperature to obtain the PANI / GO / MXene composite nonwoven evaporation film.

[0079] Step 5. Preparation of the double-layer structure light-responsive actuator (PEM flexible actuator):

[0080] First, centrifuge the MXene aqueous dispersion prepared in Step 1 at a speed of 1000 rpm for 60 minutes, collect the precipitate, disperse it in deionized water, and stir at high speed to prepare a 50% high-concentration ink; then, place the ink in a syringe equipped with a 260 mm needle, and print it on the LDPE film substrate under a gas pressure of 20 kPa, controlling the distance between the nozzle and the substrate to be 0.07 mm, the moving speed of the nozzle to be 4 mm / s, and print 5 layers layer by layer according to the pre-designed pattern; finally, after drying at room temperature for 2 hours, peel it off to form a double-layer structure film, and obtain the required PEM flexible actuator after trimming.

[0081] Step 6. Preparation of the intelligent light-tracking evaporator:

[0082] Fix the flexible actuator prepared in Step 5 and the PANI / GO / MXene composite nonwoven evaporator prepared in Step 4 together with waterproof glue to obtain the intelligent light-tracking evaporator based on the integration of MXene-based composite nonwoven fabric and film.

[0083] Example 4

[0084] This example provides a preparation method of an intelligent light-tracking evaporator based on the integration of MXene-based composite nonwoven fabric and film, and the method includes the following steps:

[0085] Step 1. Preparation of MXene nanosheets

[0086] Etch the MAX phase using LiF and HCl to remove the A layer and wash it to neutrality to obtain the MXene precursor, where: the etching time of the MAX phase is 24 h; Disperse the MXene precursor in water, and exfoliate the single-layer MXene nanosheets by ice bath ultrasonic treatment followed by two centrifugations, where: the rotation speed of the first centrifugation is 4000 r / min and the time is 20 min; the rotation speed of the second centrifugation is 10000 r / min and the time is 20 min.

[0087] Step 2. Preparation of the MXene organic dispersion:

[0088] For surface group exchange, treat the MXene aqueous dispersion in Step 1 with a TBAOH solution and centrifuge to collect the MXene precipitate; redisperse the MXene precipitate in DMAc to obtain the MXene dispersion, where: TBAOH:MXene = 5:1 (molar ratio), and the concentration of the MXene dispersion is 30 mg / ml.

[0089] Step 3. Preparation of the GO organic dispersion:

[0090] Disperse the GO dispersion in DMAc and adjust the concentration to 15 mg / ml.

[0091] Step 4. Preparation of the PGM evaporator:

[0092] First, use 6 ml of a high-concentration (15 mg / ml) GO dispersion as the substrate, add ANI and MXene (total mass is 210 mg, and the mass ratio of MXene to ANI is 8:1) to obtain the PGM4 spinning slurry; then, stir the above mixture for 15 minutes and extrude it through a syringe into a coagulation bath containing HCl and CH 3 COOH, and dropwise add an APS solution during the spinning process to promote the in-situ polymerization of aniline, with the molar ratio of APS to ANI being 1:1; finally, place the spun composite fiber at 0 °C for 24 hours, filter it under vacuum and dry it at room temperature to obtain the PANI / GO / MXene composite non-woven evaporation film.

[0093] Step 5. Preparation of the double-layer structure light-responsive actuator (PEM flexible actuator):

[0094] First, centrifuge the MXene aqueous dispersion prepared in Step 1 at a speed of 10,000 rpm for 60 minutes. After collecting the precipitate, disperse it in deionized water and stir at high speed to prepare a high-concentration ink with a concentration of 50%. Then, place the ink in a syringe equipped with a 260-mm needle and print it on the LDPE film substrate under a gas pressure of 20 kPa. Control the distance between the nozzle and the substrate to be 0.07 mm, the moving speed of the nozzle to be 4 mm / s, and print 5 layers layer by layer according to the pre-designed pattern. Finally, dry it in a normal-temperature environment for 2 hours and then peel it off to form a double-layer structure film. After trimming, the required PEM flexible actuator is obtained.

[0095] Step 6: Preparation of the intelligent light-tracking evaporator:

[0096] Fix the flexible actuator prepared in Step 5 and the PANI / GO / MXene composite non-woven fabric evaporator prepared in Step 4 together with waterproof glue to obtain the intelligent light-tracking evaporator based on the integration of MXene-based composite non-woven fabric and film.

[0097] Figure 1 It is the surface scanning electron microscope photo of the PGM evaporator obtained in Step 4 of Example 1. It can be seen from the figure that the fibers prepared by wet spinning will wrinkle on the surface after dehydration. Under the action of gravity, these fibers will fuse and overlap with each other to form stable connection points, thus constructing an integral structure and enhancing its mechanical stability.

[0098] Figure 2 It is the light absorption rate data graph of the PGM evaporator obtained in Step 4 of Example 1. Its absorption rate within the AM 1.5G solar spectrum range exceeds 92%. Such excellent absorption efficiency is mainly attributed to its multi-layer fiber structure, which can minimize the escape of incident light and promote multiple internal reflections, thus enhancing the light capture ability inside the structure.

[0099] Figure 3 It is the schematic diagram of the evaporation efficiency of the PGM evaporators obtained in Steps 4 of Examples 1-4. The evaporation rate of the PGM1 evaporator is the highest, reaching 3.43 kg·m-2, while the evaporation rate of the PGM3 evaporator is the lowest, being 2.88 kg·m-2. The evaporation efficiency of the PGM1 evaporator is as high as 232.78%.

[0100] Figure 4It is a cross-sectional scanning photograph of the light-responsive driver obtained in Step 5 of Example 1. The EDS surface scanning result of the cross-section is shown in the lower left corner, where the green part represents the distribution of Ti element, the blue part corresponds to the C element, and the red part comes from the Al element on the sample stage. Ti is the main element of the MXene coating, while C is the main component of the LDPE film. The magnified SEM image in the upper right corner shows that the MXene coating is composed of multiple layers of stacked nanosheets, and the interlayer structure is tight.

[0101] Figure 5 It is a light-tracking data graph of the intelligent light-tracking evaporator obtained in Step 6 of Example 1 under illumination of incident light at different zenith angles. The recorded deflection test shows that the MES system can effectively adapt to different zenith angle changes. When the zenith angle is 60°, the MES system exhibits the best driving performance, with the maximum deflection angle reaching 33.827°, and the corresponding theoretical light utilization efficiency increases by 83.864%. In contrast, when the zenith angle is 30°, the deflection angle drops to 16.225°, and the increase in the theoretical light utilization efficiency is only 12.51%. These results highlight the adaptability of the MES system to different incident light angles, which not only performs excellently in phototaxis driving but also significantly improves the theoretical light utilization efficiency.

Claims

1. An intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration, characterized in that The intelligent light-chasing evaporator includes a PANI / GO / MXene composite non-woven fabric evaporator located at the top and a flexible driver located at the bottom. The flexible driver drives the PANI / GO / MXene composite non-woven fabric evaporator to move toward the light under unilateral light and provides support.

2. The intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 1, characterized in that The PANI / GO / MXene composite non-woven fabric evaporator is made by wet spinning, the coagulation bath is an aqueous solution containing HCl and CH3COOH, and APS solution is added dropwise during the spinning process to promote the in-situ polymerization of aniline.

3. The intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 1, characterized in that The flexible actuator is made by attaching a MXene thin film coating to an LDPE film through ink writing. The thickness of the MXene thin film coating is 25 to 35 μm, and the thickness of the LDPE film is 35 to 50 μm.

4. A method for preparing an intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to any one of claims 1 to 3, characterized in that The method comprises the following steps: Step 1: Preparation of MXene nanosheets: Step 1: Use LiF and HCl to etch the MAX phase to remove the A layer, and wash it to neutrality to obtain a MXene precursor; Step 1 and 2: Disperse the MXene precursor in water, and exfoliate the single-layer MXene nanosheets by ice bath sonication and then centrifugation twice; Step 2: Preparation of MXene dispersion: Step 21: Obtain MXene aqueous dispersion using MILD method; Step 22: Treat the MXene aqueous dispersion prepared in step 1 with TBAOH solution to exchange surface groups and centrifuge to collect the MXene precipitate; Step 2: Re-disperse the MXene precipitate in DMAc to obtain a MXene dispersion with a concentration of 20-40 mg / ml. Step 3: Preparation of GO dispersion: Dispersing GO in DMAc to obtain a GO dispersion with a concentration of 10-20 mg / ml; Step 4: Preparation of PANI / GO / MXene composite non-woven fabric evaporator: Step 4: 5-10 ml of the GO dispersion prepared in step 3 is used as a substrate, and ANI and MXene are added to obtain a MXene / GO / ANI mixed spinning slurry, wherein: the total mass of ANI and MXene is 210 mg, and the mass ratio of MXene to ANI is 1-8:1; Step 42: inject the MXene / GO / ANI mixed spinning slurry into a coagulation bath containing HCl and CH3COOH, and dropwise add APS solution during the spinning process to promote the in-situ polymerization of aniline, with a molar ratio of APS to ANI of 1:1; Step 43: The spun composite fiber is allowed to stand at 0°C to promote in-situ polymerization; Step 44, collecting the fibers by vacuum filtration and air drying at room temperature to form a PANI / GO / MXene composite nonwoven fabric evaporator; Step 5: Preparation of flexible actuator: Step 51: purify the MXene aqueous dispersion prepared in step 1 and then disperse it to prepare printing ink, and perform pneumatic extrusion printing on an LDPE film using a microelectronic printer to deposit the ink layer by layer; Step 52: The printed double-layer film is dried, then peeled off and trimmed to obtain the desired flexible actuator.

5. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In the step 1, the MAX phase etching time is 20 to 30 hours.

6. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In the steps one and two, the first centrifugal speed is 3000-5000 r / min, and the time is 10-30 min; the second centrifugal speed is 9000-11000 r / min, and the time is 10-30 min.

7. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In step 22, TBAOH:MXene=5:1 (molar ratio).

8. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In step 43, the time of in-situ polymerization is 20 to 30 hours.

9. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In step 51, the concentration of the ink is 30-40%, the distance between the print head and the substrate is 0.07 mm, the moving speed is 2-10 mm / s, and the air pressure is 5-20 kPa.

10. The method for preparing the intelligent light-chasing evaporator based on MXene-based composite nonwoven fabric and film integration according to claim 4, characterized in that In step 52, the double-layer film is dried for 1 to 3 hours.

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