PEG (at) SiO2 (at) MXene composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of personal thermal management, and particularly discloses a PEG (at) SiO2 (at) MXene composite material and a preparation method and application thereof.The preparation method comprises the following steps that titanium aluminum carbide is etched with hydrofluoric acid, and multiple layers of MXene are obtained; the preparation method comprises the following steps: blending tetraethoxysilane and polyethylene glycol, stirring at normal temperature, and carrying out amination modification on a product to obtain a PEG (at) SiO2 nano microcapsule; and blending the PEG (at) SiO2 nano microcapsule and the multiple layers of MXene, and stirring at normal temperature, so as to obtain the PEG (at) SiO2 / MXene composite material. A PEG long chain is embedded into a SiO2 porous network to form an interpenetrating, cross-linking and coating structure, and SiO2 forms a spherical shell layer on the outer layer of PEG, so that the problem of leakage of PEG can be solved; the preparation method comprises the following steps: preparing a PEG (at) SiO2 nano-microcapsule, inserting the prepared PEG (at) SiO2 nano-microcapsule between multiple layers of MXene through a vacuum injection method, combining the PEG (at) SiO2 nano-microcapsule with the multiple layers of MXene through electrostatic adsorption to obtain the PEG (at) SiO2 MXene composite material with a sandwich structure, and the PEG (at) SiO2 MXene composite material has rapid photothermal conversion and subsequent heat storage capability and thermal cycle stability.

Description

Technical Field

[0001] The present invention relates to the technical field of personal thermal management, and particularly relates to a PEG@SiO 2 @MXene composite material, its preparation method and application. Background Art

[0002] In the cold environment in the north, personal thermal management is crucial for the health and safety of outdoor activity personnel. Traditional thermal insulation materials are difficult to meet the thermal comfort requirements in the environment with strong sunlight but low temperature. Photothermal conversion materials can convert solar energy into heat energy, providing an effective solution for personal thermal management. Due to the intermittent supply characteristics of solar energy and its climate sensitivity, the development of stable and efficient photothermal conversion technology has become a key link to improve the utilization efficiency of solar energy. Solar energy phase change heat storage materials store and release heat through solid-liquid or solid-solid phase changes, realizing efficient and stable utilization of solar energy and significantly improving the solar energy utilization efficiency. However, in practical applications, it is found that there are two technical bottlenecks in this type of material: (1) the intrinsic light absorption ability of the material is insufficient; (2) there is a risk of liquid leakage during the solid-liquid phase change process. These defects make it difficult to meet the stringent requirements of the solar thermal storage system for material stability and photothermal synergy performance.

[0003] MXene materials (such as Ti 3 C 2 T x ) have become a research hotspot in the field of personal thermal management due to their excellent photothermal conversion efficiency and antibacterial properties. MXene needs to be combined with a phase change material in practical applications to achieve heat energy storage. Polyethylene glycol (PEG), as a typical phase change material, can store and release a large amount of latent heat. However, the problem that PEG undergoes solid-liquid phase change and causes leakage limits its practical application. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a PEG@SiO 2 @MXene composite material, its preparation method and application, embed the PEG long chain into the SiO 2 porous network to form an interpenetrating, cross-linked and coated structure, and the SiO 2 forms a spherical shell layer on the outer layer of PEG, which can solve the leakage problem of PEG.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention first provides a preparation method of a PEG@SiO 2 @MXene composite material, which includes the following steps: S1. Etch aluminum carbide titanium with hydrofluoric acid to obtain multi-layer MXene; S2. Blend tetraethoxysilane and polyethylene glycol PEG and stir at room temperature, then perform amination modification on the product to obtain PEG@SiO 2 nano microcapsules; S3. Blend the PEG@SiO 2 nano microcapsules with the multi-layer MXene and stir at room temperature to obtain PEG@SiO 2 / MXene composite material.

[0006] In the present invention, SiO 2 porous network structure is formed by hydrolysis and polycondensation of tetraethoxysilane TEOS, and the long PEG chains are embedded in the SiO 2 porous network to form an interpenetrating, cross-linked and coated structure. The SiO 2 forms a spherical shell layer on the outer layer of PEG, which can solve the leakage problem of PEG. By regulating the content of different PEG long chains, the latent heat of phase change of the phase change microcapsules can be regulated, and amino groups are modified on the surface to enhance its electrostatic adsorption ability; then the prepared PEG@SiO 2 nano microcapsules are inserted into the interlayer of multi-layer MXene by vacuum injection method, and the PEG@SiO 2 nano microcapsules are combined with multi-layer MXene by electrostatic adsorption to obtain a "sandwich" structure of PEG@SiO 2 @MXene composite material. This PEG@SiO 2 @MXene composite material has rapid photothermal conversion and subsequent heat storage ability, and has thermal cycling stability.

[0007] As a further improvement of the above scheme of the present invention, in step S1, the mixing ratio of the hydrofluoric acid to Ti 3 AlC 2 is 30 - 40 mL: 2 g.

[0008] As a further improvement of the above scheme of the present invention, in step S1, the stirring reaction is carried out at room temperature for 18 - 24 h.

[0009] As a further improvement of the above scheme of the present invention, in step S2, the particle size of the PEG@SiO 2 nano microcapsules is 90 - 110 nm.

[0010] As a further improvement of the above scheme of the present invention, the specific steps of step S2 are: dissolve polyethylene glycol in a solvent, add ammonia water and disperse it by ultrasonic wave, then dropwise add tetraethoxysilane solution and continuously stir and react; add γ-aminopropyltriethoxysilane and continue to react, then centrifuge, wash, and dry.

[0011] As a further improvement of the above solution of the present invention, the dosage ratio of polyethylene glycol to ammonia water is 2-3 g: 2 mL; the concentration of ammonia water is 25 wt%-28 wt%; And / or, when dropping and reacting tetraethoxysilane solution under continuous stirring, the tetraethoxysilane solution is dropped at a rate of 70-90 μL / min and continuously stirred and reacted for 10-12 h; And / or, the volume ratio of γ-aminopropyltriethoxysilane to tetraethoxysilane is 1:3.5, and the time for the continued reaction is 10-12 h.

[0012] As a further improvement of the above solution of the present invention, in step S3, in the PEG@SiO 2 / MXene composite material, the content of the PEG@SiO 2 nano microcapsules is 85 wt%-90 wt%.

[0013] As a further improvement of the above solution of the present invention, in step S3, the hydrothermal reaction includes the following steps: dispersing the multi-layer MXene in deionized water and performing ultrasonic treatment to obtain solution A; dispersing the PEG@SiO 2 nano microcapsules in deionized water and performing ultrasonic treatment to obtain solution B; adding solution B to solution A and performing ultrasonic treatment, then allowing the obtained mixed solution to stand in a vacuum oven at 50-60 °C for vacuum impregnation, and then stirring, washing, and drying at room temperature to obtain the PEG@SiO 2 / MXene composite material.

[0014] The present invention also provides a PEG@SiO 2 / MXene composite material, which is prepared by the preparation method as described above.

[0015] The present invention also provides an application of a PEG@SiO 2 / MXene composite material prepared by the preparation method as described above as a personal thermal management material.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, a porous network structure of SiO is formed by hydrolysis and polycondensation of tetraethoxysilane (TEOS). The long PEG chains are embedded in the SiO 2 porous network to form an interpenetrating, cross-linked and coated structure. The SiO 2 forms a spherical shell layer on the outer layer of PEG, which can solve the leakage problem of PEG. By regulating the content of different PEG long chains, the latent heat of phase change of the phase change microcapsules is regulated, and amino groups are modified on the surface to enhance its electrostatic adsorption ability; then the prepared PEG@SiO 2 2 ​The nano-microcapsules are inserted into the interlayers of multi-layer MXene by the vacuum injection method, PEG@SiO 2 The nano-microcapsules are combined with multi-layer MXene by electrostatic adsorption to obtain the PEG@SiO 2 @MXene composite material with a "sandwich" structure. This PEG@SiO 2 @MXene composite material has rapid photothermal conversion and subsequent heat storage capabilities, and has thermal cycling stability.

[0017] In the present invention, the intercalation ratio of PEG@SiO 2 nano-microcapsules in multi-layer MXene can be regulated to obtain materials with different photothermal conversion performances and phase change latent heat performances to meet the requirements of different scenarios.

[0018] The preparation method of the present invention is simple, the raw materials are easy to obtain, and it can be prepared in general chemical laboratories, which is easy to promote and convenient for application in the field of personal thermal management. Description of the Drawings

[0019] Figure 1 SEM image of the PEG@SiO 2 nano-microcapsules prepared in Example 1; Figure 2 TEM image of the PEG@SiO 2 nano-microcapsules prepared in Example 1; Figure 3 SEM image of PSM-2 prepared in Example 1; Figure 4 SEM image of PSM-1 prepared in Example 2; Figure 5 SEM image of PSM-3 prepared in Example 3; Figure 6 DSC test chart of PSM-1, PSM-2 and PSM-3; Figure 7 Test result chart of the photothermal conversion performance of PSM-1, PSM-2 and PSM-3. Detailed Embodiments

[0020] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0022] Example 1 This example presents a PEG@SiO 2 @MXene composite material, and its preparation method includes the following steps: S1. Etch Ti 3 AlC 2 : Mix 2 g of Ti 3 AlC 2 with 40 mL of HF solution (≥40%) in a polytetrafluoroethylene container, and magnetically stir at room temperature for 20 h; wash the obtained suspension with deionized water until the pH of the supernatant is 6; add the suspension to ethanol and ultrasonically treat for 1 h, then wash the sample 3 times with a centrifuge, with the solvent being deionized water. After washing, take the solid, and finally dry the solid in a vacuum oven at 60°C for 12 h to obtain multilayer MXene powder.

[0023] S2. Dissolve 3 g of PEG 6000 in a solvent (obtained by mixing 15 mL of isopropyl alcohol IPA and 5 mL of deionized water), and magnetically stir at room temperature (500 rpm) until completely dissolved; add 2 mL of NH 3 ·H 2 O (concentration of 25%) and ultrasonically disperse for 5 min; to obtain a more uniform nano-microcapsule, then use a syringe pump to slowly drip the TEOS solution (obtained by mixing 350 μL of TEOS and 10 mL of IPA) into the mixture at a rate of 80 μL / min, and continuously stir for 4 h; repeat the slow dripping of 350 μL of TEOS at a rate of 80 μL / min and continuously stir for 4 h; slowly add 200 μL of APTES to conduct amino modification on the surface of PEG@SiO 2 and continue the reaction for 12 h; the product is centrifugally washed with ethanol (8000 rpm, 5 min) 3 times and vacuum dried at 60°C overnight to obtain PEG@SiO 2 nano-microcapsules.

[0024] S3. Disperse 0.1 g of the multilayer MXene obtained in step S1 in 25 mL of deionized water and ultrasonically treat for 30 min to obtain solution A; the PEG@SiO 2The nano microcapsules were dispersed in 25 mL of deionized water and ultrasonicated until the solution was clear to obtain solution B. Solution B was added to solution A, and after ultrasonic treatment for 30 min, the mixed solution was left standing in a vacuum oven at 60 °C for 3 h for vacuum impregnation. Subsequently, the obtained mixed solution was magnetically stirred at room temperature for 12 h. It was washed several times using a centrifuge with deionized water as the solvent. After washing, the solid was taken, and finally, the obtained solid was dried overnight in an oven at 60 °C to finally obtain the PEG@SiO 2 @MXene composite material, denoted as PSM-2. In the PEG@SiO 2 / MXene prepared in this example, the content of the PEG@SiO 2 nano microcapsules was 88 wt%.

[0025] Figure 1 This is the scanning electron microscopy image of the PEG@SiO 2 nano microcapsules prepared in step S2 of this example. It can be seen from Figure 1 the image that the PEG@SiO 2 nano microcapsules have good dispersibility because the amino groups modified on the surface of the PEG@SiO 2 nano microcapsules carry the same positive charge and repel each other.

[0026] Figure 2 This is the transmission electron microscopy image of the PEG@SiO 2 nano microcapsules prepared in step S2 of this example. It can be seen from Figure 2 the image that the PEG@SiO 2 nano microcapsules have a core-shell structure, and PEG is well coated in SiO 2 . The spherical shell layer on the outer layer of PEG can solve the leakage problem of PEG. 2

[0027] Figure 3 This is the scanning electron microscopy image of PSM-2 prepared in step S3 of this example. It can be clearly seen from Figure 3 the image that the PEG@SiO 2 nano microcapsules are well adsorbed on one or both sides of the interlayer of the multi-layer MXene, forming a "sandwich" structure.

[0028] Example 2 This example adopts the same implementation method as Example 1. The difference from Example 1 is that in the PEG@SiO 2 / MXene prepared in this example, the content of the PEG@SiO 2 nano microcapsules is 85 wt%. The PEG@SiO 2 / MXene prepared in this example is denoted as PSM-1. ​

[0029] Figure 4 This is the scanning electron microscope image of PSM-1 prepared in this example. It can be clearly seen from Figure 4 that the PEG@SiO 2 nano microcapsules are well adsorbed on one or both sides of the interlayer of multi-layer MXene, forming a "sandwich" structure.

[0030] Example 3 This example uses the same implementation method as Example 1. The difference from Example 1 is that in the PEG@SiO 2 / MXene prepared in this example, the content of PEG@SiO 2 nano microcapsules is 90 wt%. The PEG@SiO 2 / MXene prepared in this example is denoted as PSM-3.

[0031] Figure 5 This is the scanning electron microscope image of PSM-3 prepared in this example. It can be clearly seen from Figure 5 that the PEG@SiO 2 nano microcapsules are well adsorbed on one or both sides of the interlayer of multi-layer MXene, forming a "sandwich" structure.

[0032] Test Example 1 PSM-1, PSM-2, and PSM-3 were subjected to DSC testing (differential scanning calorimetry testing, which quantitatively measures the heat absorbed or released by a sample through a detector to study the thermal changes of the sample). The results are as shown in Figure 6 ( Figure 6 a and 6b are the crystallization peak and melting peak respectively. The integral value of the crystallization peak is the crystallization enthalpy, and the integral value of the melting peak is the melting enthalpy. The magnitudes of the crystallization enthalpy and melting enthalpy can measure the heat storage capacity of the material). It can be seen from Figure 6 that PSM-1 has good photothermal performance but poor heat storage performance; PSM-3 has good heat storage performance but poor photothermal performance; PSM-2 has both good photothermal performance and good heat storage performance.

[0033] Test Example 2 Under simulated sunlight irradiation with a power density of 0.1 W / cm 2 (equivalent to one sun intensity), the photothermal conversion performance of PSM-1, PSM-2, and PSM-3 was tested: PSM-1, PSM-2, and PSM-3 were irradiated with sunlight for 5 minutes continuously; then, the light was turned off, and the real-time temperatures of PSM-1, PSM-2, and PSM-3 within 10 minutes were recorded, obtaining the time-temperature curve as shown in Figure 7 .

[0034] It can be seen from Figure 7It can be observed that when the simulated sunlight is turned on, the temperature of all samples gradually increases with time. Specifically, after 5 minutes of irradiation, PSM-1 and PSM-2 reach 66.7 °C and 64.9 °C respectively; in contrast, the maximum temperature of PSM-3 is 54.9 °C. It can be seen that when the content of PEG@SiO 2 nano-microcapsules is insufficient, since the nano-microcapsules do not fill the interlayer of MXene, it will cause a decrease in the latent heat of phase change, resulting in a decrease in the heat storage performance; when PEG@SiO 2 nano-microcapsules have a higher content, since the microcapsules will form surface adsorption on the surface of MXene, thereby reducing the light absorption ability of the PSM composite material, and thus reducing its photothermal conversion performance. Once the simulated sunlight is turned off, all samples experience a temperature drop, and the rate of temperature drop gradually slows down with time. It should be noted that PSM-1 and PSM-2 exhibit different melting platforms, which is attributed to the solid-liquid phase transition of PEG and has the heat storage ability to keep the temperature stable for a period of time.

[0035] The present invention provides a potential multifunctional composite material for the development of personal thermal management in outdoor sunlight applications.

[0036] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0037] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a PEG@SiO2@MXene composite material, characterized in that: It includes the following steps: S1. Etching titanium aluminum carbide with hydrofluoric acid to obtain multilayer MXene; S2. Tetraethoxysilane and polyethylene glycol are mixed and stirred at room temperature, and the product is amino-modified to obtain PEG@SiO2 nanocapsules; S3. Blending the PEG@SiO2 nanocapsules with the multilayer MXene and stirring at room temperature to obtain a PEG@SiO2 / MXene composite material.

2. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: In step S1, the mixing ratio of hydrofluoric acid and Ti3AlC2 is 30-40mL:2g.

3. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: In step S1, the stirring reaction is carried out at room temperature for 18-24 hours.

4. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: In step S2, the particle size of the PEG@SiO2 nanocapsules is 90-110 nm.

5. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: The specific steps of step S2 are: dissolving polyethylene glycol in a solvent, adding ammonia water for ultrasonic dispersion, and then dropping tetraethoxysilane solution for continuous stirring reaction; adding γ-aminopropyltriethoxysilane for continuous reaction, centrifuging, washing, and drying.

6. The method for preparing the PEG@SiO2@MXene composite material according to claim 5, characterized in that: The dosage ratio of the polyethylene glycol and ammonia water is 2-3 g: 2 mL; the concentration of the ammonia water is 25 wt%-28 wt%; And / or, the step of adding the tetraethoxysilane solution dropwise under continuous stirring is to add the tetraethoxysilane solution dropwise at a rate of 70-90 μL / min and continue stirring for 10-12 hours; And / or, the volume ratio of the γ-aminopropyltriethoxysilane to the tetraethoxysilane is 1:3.5, and the reaction is continued for 10-12 hours.

7. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: In step S3, in the PEG@SiO2 / MXene composite material, the content of the PEG@SiO2 nanocapsules is 85wt%-90wt%.

8. The method for preparing the PEG@SiO2@MXene composite material according to claim 1, characterized in that: In step S3, the hydrothermal reaction includes the following steps: dispersing the multilayer MXene in deionized water and ultrasonically treating it to obtain solution A; dispersing the PEG@SiO2 nanocapsules in deionized water and ultrasonically treating it to obtain solution B; adding the solution B to the solution A and ultrasonically treating it, and then standing the obtained mixed solution in a vacuum oven at 50-60°C for vacuum impregnation, and then stirring at room temperature, washing, and drying to obtain a PEG@SiO2 / MXene composite material.

9. A PEG@SiO2 / MXene composite material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the PEG@SiO2 / MXene composite material prepared by the preparation method according to any one of claims 1 to 8 as a personal thermal management material.

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