Super-tensile high-strength intelligent driving material based on natural rubber-hydrogel heterogeneous interpenetrating network structure as well as preparation method and application of super-tensile high-strength intelligent driving material

Abstract

The invention discloses a preparation method of an intelligent driving material based on natural rubber-hydrogel, and a heterogeneous interpenetrating network intelligent driving material containing a gel network and a rubber network is obtained by compounding super-hydrophilic natural rubber latex and poly (N-isopropylacrylamide) and introducing single-sheet-layer MXene at the same time. The material disclosed by the invention not only has excellent mechanical properties (the tensile strength is 1.7 MPa, which is enhanced by 50 times or more than that of blank intelligent hydrogel) and super-tensile properties (the elongation at break can reach 1500% or more) which are far better than those of common intelligent driving hydrogel, but also keeps high photo-thermal conversion efficiency and good intelligent driving performance, can realize remote controllable near-infrared light driving, and has wide application prospects. Therefore, the method has a wide application prospect in the fields of miniature soft robots, artificial muscles, biomedicine and the like.

Description

Technical Field

[0001] The present invention relates to the field of functional polymer materials, and in particular to an ultra-stretchable high-strength intelligent driving material with a heterogeneous interpenetrating network structure based on a natural rubber-hydrogel composite, a preparation method thereof, and bionic applications. Background Art

[0002] Smart hydrogels are currently one of the most popular intelligent soft materials. Due to their unique "soft and wet" structure, which mimics biological tissue, they are widely used in soft robotics, artificial muscles, smart curtains, biomedicine, and other fields. With continuous research in recent years, smart hydrogels have become capable of achieving various complex actuations (including 2D bending and flexing, 3D twisting, spiraling, and folding), and various smart hydrogel biomimetic devices have emerged. They can be triggered by various external stimuli (including pH, temperature, magnetic fields, electric fields, and light). For example, poly (N-isopropylacrylamide) (PNIPAM) hydrogel is a typical temperature-responsive smart actuation hydrogel. When the temperature exceeds the lower critical temperature (LCST), it will produce a significant volume contraction. By designing biomimetic anisotropic structures (including layered, gradient, oriented, and patterned structures), a growing number of smart actuation hydrogels with complex deformations and movements have emerged. However, existing smart actuation hydrogels suffer from poor mechanical properties, low actuation force, and slow actuation speed.

[0003] Natural polymer materials have attracted considerable attention in recent years, with natural rubber being particularly valuable for research, as it possesses high strength and tensile strength while maintaining a low modulus. Composited with intelligent actuating hydrogels, its mechanical properties and driving force could be significantly improved. However, natural rubber blocks are relatively hydrophobic and impermeable, making it difficult to directly composite with hydrophilic hydrogels to form a heterogeneous interpenetrating network (H-IPN) structure. Therefore, it is necessary to develop a natural rubber-hydrogel composite H-IPN structure with an ultra-stretchable, high-strength intelligent actuating material. Summary of the Invention

[0004] In view of this, the present invention provides a natural rubber-hydrogel composite heterogeneous interpenetrating network structure ultra-stretchable high-strength intelligent driving material to solve the problems of poor mechanical properties and weak driving force of existing intelligent hydrogels.

[0005] The present invention adopts a method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure, comprising the following steps:

[0006] S1: Adding monomer N-isopropylacrylamide and crosslinking agent N,N-methyleneacrylamide to the aqueous dispersion of monolayer MXene, and stirring thoroughly to obtain N-isopropylacrylamide prepolymer solution containing MXene;

[0007] S2: adding natural rubber latex to the prepolymer solution obtained in step S1, and stirring evenly on an oscillator to obtain a natural rubber-hydrogel mixture;

[0008] S3: adding an initiator and a catalyst to the natural rubber-hydrogel mixture in step S2, mixing, and performing free radical polymerization to obtain a natural rubber-hydrogel material;

[0009] S4: The natural rubber-hydrogel material prepared in S3 is placed in an acetic acid solution for acidification, and then placed in an oven for drying to obtain a natural rubber-hydrogel intelligent driving material, wherein the amount of the monomer N-isopropyl acryloyl is 150-250 mg, and the amount of the natural rubber is 0.5-0.7 mg.

[0010] Preferably, the monomer N-isopropylacrylamide is 200 mg, and the monomer N,N-methyleneacrylamide is 5 mg.

[0011] Preferably, the amount of natural rubber latex used in step S2 is 1 mL, and the mass concentration is 50-70%.

[0012] Preferably, the amount of MXene used in step S1 is 10 mg.

[0013] Preferably, the drying temperature in step S4 is 50° C. and the drying time is 2 h.

[0014] Preferably, in step S3, the initiator is ammonium persulfate solution; and the catalyst is tetramethylethylenediamine.

[0015] On the other hand, the present invention provides a natural rubber-hydrogel composite heterogeneous interpenetrating network structure ultra-stretchable high-strength intelligent driving material and its application in the preparation of photothermal driven bionic device materials.

[0016] The method provided by the present invention first utilizes room-temperature free radical polymerization to polymerize poly (N-isopropylacrylamide) gel. Since natural rubber latex has nano-scale particles, they can fill the pores of the poly (N-isopropylacrylamide) gel. After acidification and drying, the rubber is solidified to construct a second network structure, thereby obtaining a heterogeneous interpenetrating network structure intelligent driving material (NR / PH) containing a gel network and a rubber network.

[0017] The NR / PH prepared by the method of the present invention not only has the excellent mechanical properties of rubber (tensile strength can reach 1.7 MPa, elongation at break can reach 1500%), but also has good photothermal response driving performance; in addition, NR / PH has high toughness, good stability and can completely restore its original shape.

[0018] Furthermore, the NR / PH prepared by the method of the present invention can realize various complex drives under the control of near-infrared light. Compared with the original ordinary smart hydrogel, its mechanical properties and driving force are significantly improved, so it can be designed as a bionic device with high-strength ultra-stretchability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the preparation process of a natural rubber-hydrogel composite heterogeneous interpenetrating network structure ultra-stretchable high-strength intelligent driving material (NR / PH) of the present invention;

[0020] Figure 2 The infrared spectra of 0.3NR / PH and NR and PH prepared in Example 1;

[0021] Figure 3 are scanning electron microscopy (SEM) images, 3a represents the cross-sectional morphology of PNIPAM hydrogel and its pore size distribution histogram; 3b represents the cross-sectional morphology of 0.3NR / PH gel in Example 1 and its pore size distribution histogram; 3c represents the cross-sectional morphology of pure natural rubber and its pore size distribution histogram; 3d represents the cross-sectional element distribution mapping (EDS-mapping) of 0.3NR / PH in Example 1;

[0022] Figure 4 The water contact angle test diagrams of NR / PH with different natural rubber contents, pure PNIPAM hydrogel and pure natural rubber;

[0023] Figure 5 Figure 5 is a mechanical property test diagram of natural rubber-hydrogel smart actuating material (NR / PH) with a rubber content of 10%-40%; 5a represents the stress-strain curve of the natural rubber-hydrogel smart actuating material (NR / PH) that has not been acid-treated and dried; 5b represents the stress-strain curve of the natural rubber-hydrogel smart actuating material (NR / PH) that has been acid-treated and dried; 5c represents a comparison diagram of the Young's modulus of the natural rubber-hydrogel smart actuating material (NR / PH) with an uncured rubber network and a cured rubber network; 5d represents a bar graph of the Young's modulus and elongation at break of pure PNIAPM hydrogel, coagulated natural rubber, and natural rubber-hydrogel smart actuating material (NR / PH) that has been acid-treated and dried;

[0024] Figure 6Figure 6a represents the volume shrinkage and expansion images of 0.3NR / PH and pure PNIPAM hydrogel in 40°C hot water in Example 1; Figure 6b represents the lower critical temperature (LCST) values ​​of NR / PH and pure PNIPAM hydrogels with different rubber concentrations tested by differential scanning calorimetry (DSC); Figure 6c represents the swelling rate curves of 0.3NR / PH, pure PNIPAM hydrogel, and pure natural rubber in Example 1;

[0025] Figure 7 The transmittance test results of PNIPAM of Comparative Example 1 and 0.3NR / PH (containing MXene and not containing MXene) of Example 1 are shown;

[0026] Figure 8 This is a thermal imaging test image of 0.3NR / PH under different light intensities in Example 1;

[0027] Figure 9 a is the bending curve of 0.3NR / PH of Example 1 under the illumination of a point light source; 9b is the recovery process after the point light source is removed; 9c represents the reversible cycle curve of 20 bending and recovery under the illumination of a 0.3NR / PH point light source; (Scale bar: 5 mm);

[0028] Figure 10 This is the 0.3NR / PH driving application of Example 1. 10a represents that 0.3NR / PH is driven quickly under the illumination of a point light source and lifts a heavy object; 10b represents that 0.3NR / PH can realize the letter "W" and square pattern through remote control. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0031] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0032] The MXene material of the present invention was purchased from Shandong Enyan New Material Technology Co., Ltd., and the natural rubber emulsion was purchased from Guangdong Hongke Chemical Raw Materials Co., Ltd. The mass concentration of the natural rubber emulsion was 60%.

[0033] Example 1: Figure 1 , a natural rubber-hydrogel composite heterogeneous interpenetrating network structure ultra-stretchable high-strength intelligent driving material, prepared by the following method:

[0034] S1: Take 1 mL of 10 mg / mL MXene aqueous solution, add 200 mg of monomer N-isopropylacrylamide (NIPAM) and 5 mg of N,N'-Methylenebisacrylamide (BIS), and stir thoroughly on an oscillator for 10 min to obtain N-isopropylacrylamide prepolymer containing MXene;

[0035] S2: Take 1 mL of 60% natural rubber latex (natural rubber dosage is 0.6 mg) and add it to 1 mL of N-isopropyl acryloyl prepolymer solution. Place it on a vortex mixer and mix for 5 minutes to obtain a natural rubber-hydrogel mixture. Then store it in a refrigerator at 5°C.

[0036] S3: Add 90 μL of 4% ammonium persulfate solution (APS) and 9 μL of tetramethylethylenediamine (TEMED) to the natural rubber-hydrogel mixture of step S2, place the mixture on a vortex mixer and mix for 5 seconds, then pour the mixture into a mold and polymerize at 5°C for 20 minutes to obtain a natural rubber-hydrogel material;

[0037] S4: After the natural rubber-hydrogel smart driving material is soaked in a 0.1 mol / L acetic acid solution for 2 hours, it is taken out and placed in a 50°C oven for 2 hours, and then immersed in deionized water to allow it to absorb water and recover, thereby obtaining an ultra-stretchable and photothermally driven natural rubber-hydrogel smart driving material (0.3NR / PH).

[0038] In another embodiment, the monomer N-isopropyl acryloyl is 200 mg and the amount of natural rubber is 0.5 mg.

[0039] In another embodiment, the monomer N-isopropyl acryloyl is 250 mg and the amount of natural rubber used is 0.7 mg.

[0040] Example 2: This example differs from Example 1 in that the mass fraction of the natural rubber latex in step S2 is 20%, and the remaining steps S1, S3, and S4 are the same as in Example 1. Finally, 0.1NR / PH (the mass concentration of the natural rubber latex in the natural rubber-hydrogel system is 10%) is prepared.

[0041] Example 3: The difference between this example and Example 1 is that natural rubber latex with a mass concentration of 40% is added in step S2, and the remaining steps S1, S3 and S4 are the same as those in the example, and finally 0.2NR / PH is prepared (the mass concentration of natural rubber latex in the natural rubber-hydrogel system is 20%).

[0042] Example 4: The difference between this example and Example 1 is that natural rubber latex with a mass concentration of 80% is added in step S2, and 0.4NR / PH is finally prepared (the mass concentration of natural rubber latex in the natural rubber-hydrogel system is 40%).

[0043] Comparative Example 1: The main difference between Comparative Example 1 and Example 1 is that the acidification and curing treatment in step S4 is not performed.

[0044] Comparative Example 2: The main difference between Comparative Example 2 and Example 2 is that the acidification and curing treatment in step S4 is not performed.

[0045] Comparative Example 3: The main difference between Comparative Example 3 and Example 3 is that the acidification and curing treatment in step S4 is not performed.

[0046] Comparative Example 4: The main difference between Comparative Example 4 and Example 4 is that the acidification and curing treatment in step S4 is not performed.

[0047] Comparative Example 5: PNIPAM hydrogel was prepared by the following method: 200 mg of monomer NIPAM and 5 mg of cross-linker BIS were weighed and added to 2 mL of water and mixed on a vortex for 5 minutes to obtain a hydrogel prepolymer solution; 80 μL APS and 8 μL TEMED were added to the hydrogel prepolymer solution and mixed on a vortex for 5 seconds, and then added to a mold and polymerized at 5°C for 10 minutes to obtain PNIPAM hydrogel (N-isopropylacrylamide Hydrogel, PH).

[0048] Comparative Example 6: 2 mL of 60% natural rubber latex was weighed and poured into a mold, and dried in an oven at 50° C. for 5 h. After drying, the mold was taken out and soaked in deionized water to obtain natural rubber (NR).

[0049] Comparative Example 7: The main difference between Comparative Example 7 and Example 1 is that step S4 is treated using the existing rubber curing method (acidification or drying). It is found that the treatment conditions have a significant effect on the mechanical properties of the prepared material. As shown in Table 1, the natural rubber-hydrogel smart driving material (0.3NR / PH) after acid treatment + drying treatment has excellent mechanical properties.

[0050] Table 1 Effect of existing rubber curing method in step S4 on mechanical properties of materials

[0051] project Acid treatment drying Acid treatment + drying tensile strength 0.323MPa 0.97MPa 1.34MPa Elongation at break 298％ 678％ 1332％

[0052] The materials prepared in the above examples and comparative examples were characterized and tested:

[0053] (1) The NR / PH prepared in Example 1 was subjected to infrared testing. Figure 2 The results show that NR / PH was successfully prepared. From the FT-IR graph, it can be seen that NR / PH has a peak at 837 cm -1 The obvious peak at is mainly attributed to the C-H bending vibration near the C=C double bond, which is mainly derived from the -CH2 in the rubber isoprene structure. This indicates the formation of a heterogeneous interpenetrating network structure of rubber network-hydrogel network in NR / PH.

[0054] (2) Scanning electron microscopy (SEM) was performed on the NR / PH prepared in Example 1 to characterize its micromorphology. Figure 3 From the cross-sectional morphologies of PNIPAM hydrogel containing MXene (3a), NR / PH (3b) and NR (3c), it is observed that the pore size of NR / PH is concentrated in the middle due to the introduction of rubber network. Smaller than the pores of PNIPAM hydrogel (the pore size of PNIPAM hydrogel is approx. ), indicating the formation of a PNIPAM hydrogel network and a rubber network within the NR / PH actuating material. (3d) Elemental analysis using EDS mapping reveals distinct S and Ti elements within the NR / PH actuating material. The S element primarily originates from the natural rubber network, while the Ti element primarily originates from the MXene-containing hydrogel network. This further demonstrates the formation of a natural rubber-hydrogel "heterogeneous interpenetrating network" structure within the NR / PH smart actuating material.

[0055] (3) The water contact angles of pH and different concentrations of NR / PH were tested, such as Figure 4 The results show that the pH water contact angle is as low as 29°, indicating good hydrophilicity. When compounded with natural rubber, the 0.3NR / PH water contact angle reached 82° due to the hydrophobicity of the rubber after cross-linking. This further demonstrates that 0.3NR / PH maintains good hydrophilicity and indirectly indicates that the natural rubber latex successfully forms a hydrophobic secondary cross-linked network within the pores of the PNIPAM hydrogel after acid treatment.

[0056] (4) This study tested the mechanical properties of NR / PH and pure PNIPAM hydrogels with different rubber content. Figure 5As shown in Table 2, Figure 5a shows the stress-strain curves of NR / PH with rubber contents ranging from 10% to 40% before cross-linking with acid treatment. As can be seen from the figure, with increasing rubber content, the tensile strength of NR / PH increases from 0.128 MPa to 0.335 MPa, reaching a tensile strength 10 times that of pure PNIPAM hydrogel. This is primarily due to the formation of hydrogen bonds between proteins and fatty acids on the surface of the rubber latex particles and the PNIPAM hydrogel network, enhancing the tensile properties of the PNIPAM hydrogel. Furthermore, excessive rubber latex content can cause some latex particles to agglomerate, further enhancing the tensile strength of the gel material. Figure 5b shows the stress-strain curves of NR / PH with rubber contents ranging from 10% to 40% after acid treatment and drying. As can be seen from the figure, when the rubber content reaches 30%, the tensile strength of NR / PH reaches over 50 times that of pure PNIPAM hydrogel, and the elongation at break reaches over 1500%, 19 times that of pure PNIPAM hydrogel. Moreover, the tensile strength and elongation at break of NR / PH with corresponding rubber content are significantly improved compared with NR / PH that has not been cured by acid treatment. This shows that the intelligent driving material after acid treatment and drying has already exhibited the excellent mechanical properties of natural rubber. Figure 5c shows the Young's modulus of NR / PH with different natural rubber contents before and after acid treatment and drying. The data in the figure show that NR / PH is cured after the natural rubber content reaches 30%. Due to the cured second network, the Young's modulus increases to 2 times that of pure PNIPAM hydrogel. Even so, the NR / PH still has a lower modulus, which is beneficial to the driving of PNIPAM hydrogel. Figure 5d compares the Young's modulus and elongation at break of PNIPAM hydrogel, NR and 0.3NR / PH. The comparison shows that the 0.3NR / PH prepared by the method of the present invention has a lower modulus and super tensile properties.

[0057] Table 2 Mechanical properties test results of materials prepared in different embodiments and comparative examples

[0058] project tensile strength Elongation at break Young's modulus Example 1 1.34MPa 1332％ 0.467MPa Example 2 0.13MPa 159％ 0.125MPa Example 3 0.54MPa 398％ 0.166MPa Example 4 1.71MPa 1510％ 0.528MPa Comparative Example 1 0.275MPa 232％ 0.173MPa Comparative Example 2 0.128MPa 137％ 0.126MPa Comparative Example 3 0.168MPa 167％ 0.130MPa Comparative Example 4 0.335MPa 240％ 0.199MPa Comparative Example 5 0.0037MPa 70％ 0.117MPa Comparative Example 6 2.33MPa 1196％ 0.178MPa

[0059] (5) The temperature response driving performance of 0.3NR / PH was studied, such as Figure 6As shown in Figure 6a, 0.3NR / PH and pure PNIPAM hydrogels were placed in 40°C hot water to achieve swelling equilibrium. PNIPAM exhibited significant volume shrinkage, while 0.3NR / PH exhibited greater volume shrinkage, indicating that the formation of the rubber secondary network did not affect the temperature responsiveness of the PNIPAM network. As shown in Figure 6b, differential scanning calorimetry (DSC) plots reveal that NR / PH at varying concentrations exhibited temperature responsiveness around 34°C. Furthermore, as the rubber content increased, the hydrophobicity increased, leading to a gradual decrease in the lower critical transition temperature (LCST) of NR / PH. Figure 6c shows the swelling ratio curves for 0.3NR / PH, PNIPAM hydrogel, and natural rubber. Analysis of these curves reveals that 0.3NR / PH exhibited significant swelling changes. Because the internal rubber network did not respond to hot water, the relatively small swelling ratio of 0.3NR / PH did not affect its volume change.

[0060] (6) Study on the photothermal response performance of natural rubber-hydrogel intelligent driving material (0.3NR / PH), such as Figure 7 The results show that the PNIPAM hydrogel has high transmittance. The transmittance of NR / PH without MXene (appears white) at 808nm is 2.4%, while the NR / PH with MXene appears black and has a transmittance of 0 at 808nm. This shows that the 0.3NR / PH of Example 1 has excellent light absorption properties.

[0061] In order to further study the photothermal conversion efficiency under 808nm near-infrared light irradiation, as Figure 8 As shown in a, a circular 0.3NR / PH sample with a diameter of 1 cm was prepared and placed in deionized water at 20°C. It was irradiated with near-infrared light sources of different powers to observe the temperature changes. As can be seen from the figure, with the increase of light intensity, the temperature rise rate within 70 seconds continued to accelerate, and the highest temperature under different light intensities rose from 41°C to 72°C. When the light intensity reached 4W / cm 2 After that, the temperature reaches the response temperature of the NR / PH smart driver material within 10 seconds. As shown in Figure 8b, the heating rate and final temperature of the NR / PH smart driver material increase with increasing illumination power. This demonstrates that the NR / PH prepared by the present method has excellent photothermal conversion efficiency and can reach the LCST temperature of the PNIPAM hydrogel in a relatively short time under near-infrared light irradiation, achieving a rapid response.

[0062] (7) Study on the bending performance of 0.3NR / PH, such as Figure 9As shown in the results of Figures a and 9b, a strip of NR / PH (10 mm long, 2 mm wide, and 0.5 mm thick) was irradiated with a point light source (12 W / cm2). The efficient photothermal conversion and the hydrophobicity of the rubber network allowed NR / PH to expel water in a relatively fast time and achieve a 0-90° bend within 1.6 seconds (bending speed of 56.25° / s). When the point light source was removed, NR / PH was able to return to its original shape within 270 seconds. Figure 9 c shows: After 20 bending cycle tests, it is shown that NR / PH has good bending and recyclability.

[0063] (8) Research on intelligent driving applications of 0.3NR / PH

[0064] like Figure 10 As shown in the figure, a 0.3NR / PH smart driver (length 12mm, width 3mm, thickness 0.5mm, mass 10mg) is taken, and a weight of 800mg is hung below. When a point light source (12W / cm 2 ) irradiation, the NR / PH smart actuator can lift an object in 2.5 seconds (it can lift an object 80 times its own weight). Compared with ordinary PNIPAM hydrogels, the driving force of the NR / PH smart actuator is greatly improved. Under the control of near-infrared light, NR / PH can achieve various complex 3D patterning. For example, the straight NR / PH can spell out the letter "W" by irradiating different positions, and by changing the irradiation position, the letter "W" can be changed to "square" in a very short time. This method can be used to realize encrypted information exchange. Through remote control, NR / PH can achieve complex patterns and has a high driving force. Combining the excellent mechanical properties of rubber and the good driving performance of PNIPAM hydrogel, an intelligent driving material with ultra-stretchable high strength has been developed, which can be used to design various complex bionic devices.

[0065] In summary, the present invention utilizes the method provided to prepare a natural rubber-hydrogel composite heterogeneous interpenetrating network structure with an ultra-stretchable, high-strength intelligent driving material. This material not only exhibits superior ultra-stretching properties (elongation at break exceeding 1500%) and high strength (tensile strength reaching 1.7 MPa, 50 times that of a blank hydrogel), surpassing conventional smart hydrogels, but also exhibits temperature-responsive properties.

[0066] Furthermore, based on the "heterogeneous interpenetrating" network structure of natural rubber-hydrogel smart driving materials (NR / PH), the low-modulus rubber network overcomes the contradiction between the elasticity and toughness of existing smart hydrogels, while improving the driving force of the gel, and can achieve various multi-cycle responses.

[0067] Furthermore, the present invention introduces a single-layer MXene, which gives the hydrogel excellent photothermal conversion efficiency and develops a smart hydrogel with ultra-stretching, high-strength, and fast photothermal response driving performance.

[0068] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure, characterized in that The following steps are involved: S1: Adding monomer N-isopropylacrylamide and crosslinking agent N,N-methyleneacrylamide to the aqueous dispersion of monolayer MXene, and stirring thoroughly to obtain N-isopropylacrylamide prepolymer solution containing MXene; S2: adding natural rubber latex to the prepolymer solution obtained in step S1, and stirring evenly on an oscillator to obtain a natural rubber-hydrogel mixture; S3: adding an initiator and a catalyst to the natural rubber-hydrogel mixture in step S2, mixing, and performing free radical polymerization to obtain a natural rubber-hydrogel material; S4: The natural rubber-hydrogel material prepared in S3 is placed in an acetic acid solution for acidification, and then placed in an oven for drying to obtain a natural rubber-hydrogel intelligent driving material, wherein the amount of the monomer N-isopropyl acryloyl is 150-250 mg, and the amount of the natural rubber is 0.5-0.7 mg.

2. The method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure according to claim 1, characterized in that: The monomer N-isopropyl acryloyl is 200 mg, and the monomer N,N-methylene acrylamide is 5 mg.

3. The method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure according to claim 1, characterized in that: In step S2, the amount of natural rubber latex used is 1 mL, and the mass concentration is 50-70%.

4. The method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure according to claim 1, characterized in that: The amount of MXene used in step S1 is 10 mg.

5. The method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure according to claim 1, characterized in that: In step S4, the drying temperature is 50° C. and the drying time is 2 h.

6. The method for preparing an ultra-stretchable high-strength intelligent driving material based on a natural rubber-hydrogel heterogeneous interpenetrating network structure according to claim 1, characterized in that: In step S3, the initiator is ammonium persulfate solution; the catalyst is tetramethylethylenediamine.

7. An ultra-stretchable, high-strength intelligent driving material based on a natural rubber-hydrogel composite heterogeneous interpenetrating network structure prepared according to the method according to any one of claims 1 to 6.

8. Application of the natural rubber-hydrogel composite heterogeneous interpenetrating network structure ultra-stretchable high-strength intelligent driving material according to claim 7 in the preparation of photothermal driven bionic device materials.

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