A method for preparing an anisotropic aerogel-induced gelatin hydrogel actuator

Abstract

The application provides a preparation method of an anisotropic aerogel-induced gelatin hydrogel driver and belongs to the field of hydrogel drivers. An anisotropic chitosan aerogel is used as a skeleton, and a gelatin hydrogel is used as a muscle. The anisotropic chitosan aerogel and the gelatin hydrogel synergistically act in a driver frame to construct a heterogeneous hydrogel driver with excellent mechanical properties and multi-solvent responsiveness. The composite driver has good mechanical properties and driving performance, presents multi-solvent responsiveness, and has a simple preparation method and low cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrogel actuators, and particularly relates to a preparation method of anisotropic aerogel-induced gelatin hydrogel actuator. BACKGROUND

[0002] Hydrogel is a three-dimensional cross-linked polymer material with high water content, which is widely used in coatings, adhesives, implantable electronic products, energy storage devices, tissue engineering, drug delivery and artificial muscles. Responsive hydrogels can be triggered by pressure, temperature, light, pH, ions, solvents, electric and magnetic fields and other specific external stimuli, and exhibit three-dimensional controllable and programmable shape transformation, thus attracting much research interest as environment-responsive actuators. However, there are still some problems in the research and practical application of hydrogel actuators. First, homogeneous hydrogels usually realize macroscopic swelling or shrinking under uniform external stimuli. In order to realize specific deformation, various anisotropic structures need to be designed and manufactured for hydrogel actuators, including double-layer structure, gradient structure, patterned structure, directional structure and other anisotropic structures. Second, the high water content and loose cross-linking of hydrogels make them soft and fragile in practical application. Although various progress has been made in toughening hydrogels by forming double networks, adding nano-filler and mechanical training, there is still a significant difference in mechanical properties compared with water-free polymers. The driving behavior of these toughened hydrogels has not been paid enough attention. Therefore, how to improve the mechanical properties and deformation ability of responsive hydrogel actuators is an important problem in the wide application of hydrogel actuators. SUMMARY

[0003] To solve the above technical problems, the present application provides a preparation method of anisotropic aerogel-induced gelatin hydrogel actuator. The prepared aerogel / hydrogel composite actuator has excellent mechanical properties and multi-solution ion responsiveness. The method is simple, environmentally friendly and the prepared hydrogel actuator has excellent driving performance.

[0004] To achieve the above technical purpose, the present application provides a preparation method of anisotropic aerogel-induced gelatin hydrogel actuator, which specifically comprises the following steps:

[0005] (1) Preparation of raw materials: add chitosan and glacial acetic acid into deionized water, stir at room temperature to obtain a chitosan solution, and then remove water bubbles by ultrasonic treatment for standby use; add glutaraldehyde into deionized water and stir to obtain a glutaraldehyde solution as a cross-linking agent for standby use; add a gelatin solution into deionized water, stir in a water bath and ultrasonic treatment to obtain a gelatin solution for standby use;

[0006] (2) Preparation of chitosan aerogel framework: chitosan solution is injected into the mold, and then the mold is placed on the pre-cooled freezing device, the bottom end of the mold is close to the cold source, the temperature forms directional conduction from the bottom up, and the chitosan solution forms ice blocks with anisotropic structure; after the sample is completely frozen, it is demolded and freeze-dried, the sample after freeze-drying is soaked in sodium hydroxide ethanol solution to remove ice acetic acid; then the sample is soaked in deionized water to dilute sodium hydroxide in the sample, and finally the sample is freeze-dried again to obtain anisotropic chitosan aerogel framework;

[0007] (3) Preparation of chitosan-gelatin composite hydrogel driver: gelatin solution is added to the chitosan aerogel framework and placed in a 4℃ environment, in order to fully add the gelatin solution to the aerogel framework, the chitosan aerogel framework is soaked in the gelatin solution and placed in a freeze dryer for vacuum treatment, during the vacuum process, the gas in the aerogel framework is sucked out, and the gelatin solution fully enters the aerogel framework under the action of gas pressure, the gelatin forms a reticular structure at low temperature and is liquefied again by heating; in order to increase the stability, after the gelatin is gelled, the sample is soaked in glutaraldehyde to make the gelatin chemically cross-linked, the molecular chain forms a stable reticular structure, and the gelatin hydrogel is more stable, and finally the sample is taken out to obtain the chitosan-gelatin composite hydrogel driver.

[0008] Further, the concentration of the chitosan solution in step (1) is 1-3%, and the stirring time is 6-8h.

[0009] Further, the concentration of the glutaraldehyde solution in step (1) is 0.5-1.5%, and the stirring time is 20-50min.

[0010] Further, the concentration of the gelatin hydrogel in step (1) is 5-20%, the water bath temperature is 45-60℃, and the stirring time is 1-2h.

[0011] Further, the mold in step (2) is composed of copper sheet, glass sheet and silica gel, and the length, width and height are 40mm, 10mm and 1mm respectively.

[0012] Further, the concentration of the sodium hydroxide ethanol solution in step (2) is 0.4%, and the soaking time is 30-60min.

[0013] Further, after the sample soaked in the sodium hydroxide ethanol solution in step (2), the sample is soaked in deionized water for 3h, and the deionized water needs to be replaced constantly to dilute and remove sodium hydroxide in the sample.

[0014] Further, the freezing device in step (2) is set to a temperature of-30 to-90℃, and the freezing time is 1-3h.

[0015] Further, the sample in step (3) is soaked in glutaraldehyde for 6-12 hours.

[0016] Compared with the prior art, the application has the following beneficial effects:

[0017] (1) The application is based on the skeleton and muscle system of human body to prepare an aerogel / hydrogel composite structure as an intelligent driver, an anisotropic chitosan aerogel is used as a skeleton, and a gelatin hydrogel is filled into the aerogel as a responsive muscle, and the anisotropic aerogel skeleton prepared by the ice template method is not only beneficial to the driving of the driver composite material, but also improves the mechanical properties of the driver.

[0018] (2) The composite driver has excellent mechanical properties, and the tensile stress and compressive stress can reach the MPa level, and can respond in various ionic solutions and organic solvents.

[0019] (3) The application provides a simple and green method for constructing a responsive hydrogel, and has a wide application prospect in the fields of intelligent drivers, soft robots, microfluids and intelligent human-machine interfaces. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A flow chart for the ice template method for preparing chitosan aerogel;

[0021] Figure 2 SEM images of chitosan aerogels prepared at different directional freezing temperatures;

[0022] Figure 3 Driving and recovery of the composite driver prepared at different directional freezing temperatures;

[0023] Figure 4 Mechanical property characterization of gelatin hydrogel before and after soaking in ammonium sulfate solution at different concentrations (1 mol / L, 2 mol / L, 3 mol / L);

[0024] Figure 5 Mechanical property characterization of the composite driver and the pure gelatin hydrogel driver;

[0025] Figure 6 Driving and recovery of the composite driver in different ionic solutions and organic solutions;

[0026] Figure 7 Photos of the bending and recovery process of the composite driver in different ionic solutions;

[0027] Figure 8 Photos of the bending and recovery process of the composite driver in different organic solvents. DETAILED DESCRIPTION

[0028] To deepen the understanding of the present application, the following examples are further described in conjunction with the present application, which cannot be understood as a limitation on the technical solutions.

[0029] Example 1

[0030] A preparation method of an anisotropic aerogel-induced gelatin hydrogel driver, specifically comprising the following steps:

[0031] (1) Preparation of raw materials: 2 g of chitosan and 2 mL of glacial acetic acid were added to 98 mL of deionized water, stirred at room temperature for 8 h to obtain a chitosan solution, and then ultrasonic was performed for 10 min to remove water bubbles for use; 1 mL of glutaraldehyde was added to 99 mL of deionized water and stirred to obtain a glutaraldehyde solution as a crosslinking agent for use; 10 g of gelatin solution was added to 90 mL of deionized water, stirred in a 50℃ water bath for 1 h, and ultrasonic was performed to obtain a gelatin solution for use.

[0032] (2) Preparation of chitosan aerogel skeleton: The process flow of preparing the chitosan aerogel skeleton by ice template method is shown in Figure 1 . The chitosan solution was injected into a mold composed of a copper sheet, a glass sheet, and silica gel, and the mold had a length, width, and height of 40 mm, 10 mm, and 1 mm, respectively. The mold was placed on a pre-cooled freezing device, and the temperature was set to -30℃. The copper sheet was placed near the cold source. The temperature was conducted directionally from the copper sheet upwards, and the chitosan solution formed an ice block with anisotropic structure. After the sample was completely frozen, it was demolded and freeze-dried. The freeze-dried sample was immersed in a 0.4% sodium hydroxide ethanol solution for 30 min to remove glacial acetic acid. Then the sample was immersed in deionized water for 3 h, and the deionized water was replaced frequently to dilute and remove sodium hydroxide in the sample. Finally, the sample was freeze-dried again to obtain an anisotropic chitosan aerogel skeleton.

[0033] (3) Preparation of chitosan-gelatin composite hydrogel driver: The gelatin solution was added to the chitosan aerogel skeleton and placed in a 4℃ environment. To ensure that the gelatin solution is fully added to the aerogel skeleton, the chitosan aerogel skeleton was immersed in the gelatin solution and placed in a freeze dryer for vacuum treatment. During the vacuum process, the gas in the aerogel skeleton was sucked out, and the gelatin solution fully entered the aerogel skeleton under the action of air pressure. Gelatin forms a network structure at low temperature, which is unstable. Heating will accelerate the movement of molecular chains and make them liquefy again. To increase the stability, after the gelatin is gelatinized, the sample is immersed in 1% glutaraldehyde for 8 h to make the gelatin chemically crosslinked, and the molecular chains form a stable network structure, making the gelatin hydrogel more stable. Finally, the sample was taken out to obtain a chitosan-gelatin composite hydrogel driver.

[0034] Anisotropic chitosan aerogel was prepared by ice templating method. By controlling the temperature gradient of freezing element (chitosan solution), the solution was first crystallized on the freezing surface to form nuclei, and then grew along the temperature gradient to form ice crystals with directional structure, obtaining the directional gradient structure of chitosan aerogel skeleton. As shown in Figure 3 a, the chitosan aerogel skeleton presents two different structures, i.e. the lower dense pore layer and the upper directional macropore layer. The thickness of the dense pore layer at the bottom is 1020 μm, and the thickness ratio of the macropore layer to the dense pore layer is 2:1, as shown in Figure 2 a. The chitosan aerogel with directional and ordered structure is obviously deformed in bending in 3 mol / L ammonium sulfate solution, with a maximum bending angle of 553° and a bending rate of 3.2° / s, as shown in Figure 5 .

[0035] Example 2

[0036] A preparation method of anisotropic aerogel induced gelatin hydrogel actuator, specifically comprising the following steps:

[0037] (1) Preparation of raw materials: 2 g of chitosan and 2 mL of glacial acetic acid were added to 98 mL of deionized water, stirred at room temperature for 8 h to obtain a chitosan solution, and then ultrasonic was used for 10 min to remove water bubbles for use; 1 mL of glutaraldehyde was added to 99 mL of deionized water and stirred to obtain a glutaraldehyde solution as a crosslinking agent for use; 10 g of gelatin solution was added to 90 mL of deionized water, stirred in a 50°C water bath for 1 h, and ultrasonic was used to obtain a gelatin solution for use.

[0038] (2) Preparation of chitosan aerogel skeleton: The process flow of preparing chitosan aerogel skeleton by ice templating method is shown in Figure 1 . The chitosan solution was injected into a mold composed of a copper sheet, a glass sheet and silica gel, with a length, width and height of 40 mm, 10 mm and 1 mm, respectively. The mold was placed on a pre-cooled freezing device, with the temperature set to -60°C, and the copper sheet side close to the cold source. The temperature was conducted directionally from the copper sheet upwards, and the chitosan solution formed an ice block with anisotropic structure. After the sample was completely frozen, it was demolded and freeze-dried, and the freeze-dried sample was immersed in 0.4% sodium hydroxide ethanol solution for 30 min to remove glacial acetic acid. Then the sample was immersed in deionized water for 3 h, and the deionized water was replaced constantly to dilute and remove sodium hydroxide in the sample. Finally, the sample was freeze-dried again to obtain anisotropic chitosan aerogel skeleton.

[0039] (3) Preparation of chitosan-gelatin composite hydrogel actuator: The gelatin solution is added to the chitosan aerogel framework and placed in a 4°C environment. To allow the gelatin solution to be fully added to the aerogel framework, the chitosan aerogel framework is soaked in the gelatin solution and placed in a freeze dryer for vacuum treatment. During the vacuum extraction process, the gas in the aerogel framework is sucked out, and the gelatin solution fully enters the aerogel framework under the action of air pressure. Gelatin forms a reticular structure at low temperature and is unstable, and heating can accelerate the molecular chain movement and make it liquefy again. To increase the stability, after the gelatin is gelled, the sample is soaked in 1% glutaraldehyde for 8h to make the gelatin chemically cross-linked, and the molecular chain forms a stable reticular structure, so that the gelatin hydrogel is more stable, and finally the sample is taken out to obtain the chitosan-gelatin composite hydrogel actuator.

[0040] The decrease of freezing temperature, the shortening of crystallization and nucleation time, and the thinning of the dense pore layer related to crystallization and nucleation. The anisotropic chitosan aerogel framework prepared at -60°C has a dense pore layer thickness of 505μm at the bottom, and the ratio of the large pore layer to the dense pore layer thickness is 5:1, as shown in FIG. b. Compared with the chitosan aerogel prepared at -30°C, the driving performance of the composite actuator prepared at -60°C is further improved, and the maximum bending angle in 3mol / L ammonium sulfate solution is 361°, and the bending rate can reach 5.4° / s, as shown in FIG. c. Figure 2 Figure 5

[0041] Example 3

[0042] A preparation method of an anisotropic aerogel induced gelatin hydrogel actuator, specifically comprising the following steps:

[0043] (1) Preparation of raw materials: 2g of chitosan and 2mL of glacial acetic acid are added to 98mL of deionized water, stirred at room temperature for 8h to obtain a chitosan solution, and then ultrasonic for 10min to remove water bubbles for use; 1mL of glutaraldehyde is added to 99mL of deionized water and stirred to obtain a glutaraldehyde solution as a crosslinking agent for use; 10g of gelatin solution is added to 90mL of deionized water, stirred in a 50°C water bath for 1h and ultrasonic to obtain a gelatin solution for use.

[0044] (2) Preparation of chitosan aerogel framework: The process flow of preparing chitosan aerogel framework by ice template method is as shown in FIG. a. Figure 1 ​​The chitosan solution was injected into a mold consisting of a copper sheet, a glass sheet and silica gel. The mold was 40 mm long, 10 mm wide and 1 mm high. The mold was placed on a pre-cooled freezing device, and the temperature was set to -90°C. The copper sheet was placed near the cold source. The temperature was conducted from the copper sheet upwards, and the chitosan solution formed ice blocks with an anisotropic structure. After the sample was completely frozen, it was removed from the mold and freeze-dried. The freeze-dried sample was immersed in a 0.4% sodium hydroxide ethanol solution for 30 min to remove the ice acetic acid. The sample was then immersed in deionized water for 3 h, and the deionized water was replaced several times to dilute and remove the sodium hydroxide in the sample. Finally, the sample was freeze-dried again to obtain the anisotropic chitosan aerogel framework.

[0045] (3) Preparation of the chitosan-gelatin composite hydrogel actuator: The gelatin solution was added to the chitosan aerogel framework and placed in a 4°C environment. To ensure that the gelatin solution is fully added to the aerogel framework, the chitosan aerogel framework was immersed in the gelatin solution and placed in a freeze dryer for vacuum treatment. During the vacuum extraction process, the gas in the aerogel framework was extracted, and the gelatin solution was fully introduced into the aerogel framework under the action of gas pressure. Gelatin forms a network structure at low temperatures, which is unstable. Heating can accelerate the movement of molecular chains and make them liquefy again. To increase the stability, the sample was immersed in 1% glutaraldehyde for 8 h after gelation to allow the gelatin to be chemically cross-linked, and the molecular chains formed a stable network structure, making the gelatin hydrogel more stable. Finally, the sample was removed to obtain the chitosan-gelatin composite hydrogel actuator.

[0046] At -90°C, the bottom dense pore layer is thinner, with a thickness of 115 μm, and the ratio of the thickness of the large pore layer to the dense pore layer is 29:1, as shown in FIG. 4c. The pore size of the bottom surface of all aerogel frameworks is almost the same, while the pore size of the top surface decreases with decreasing freezing temperature. The composite actuator prepared at -90°C has a larger difference in the thickness of the two layers, and the driving performance is also better. The maximum bending angle of the composite actuator in a 3 mol / L ammonium sulfate solution is 730°, and the bending rate can reach 5.6° / s, as shown in FIG. 4d. The lower the temperature of the aerogel framework prepared by the ice mold method, the better the driving performance of the composite actuator. When the composite actuator and the pure gelatin hydrogel actuator are immersed in a 3 mol / L ammonium sulfate solution, the maximum tensile stress and compressive stress of the gelatin hydrogel increase to 1.6 MPa and 5.1 MPa, respectively, and the deformation increases several times, as shown in FIG. 4e. The aerogel framework also plays an important role in improving the mechanical properties of the composite actuator. Compared with the gelatin gel, the maximum tensile stress of the composite actuator is 1.9 MPa, the maximum compressive stress is 3.5 MPa, the maximum tensile and compressive deformation reaches 120% and 80%, respectively, and the Young's modulus also increases, as shown in FIG. 4f. Figure 2 Figure 5 Figure 4 Figure 5 ​​​The addition of aerogel skeleton limits the tensile and compressive deformation of gelatin hydrogel to some extent, but increases the stiffness of the composite, making it not easy to be brittle ground and broken, and the overall improvement of mechanical properties is still obvious.

[0047] Example 4

[0048] A preparation method of an anisotropic aerogel induced gelatin hydrogel actuator, specifically comprising the following steps:

[0049] (1) Preparation of raw materials: 2 g of chitosan and 2 mL of glacial acetic acid were added to 98 mL of deionized water, stirred at room temperature for 8 h to obtain a chitosan solution, and then ultrasonic for 10 min to remove water bubbles for use; 1 mL of glutaraldehyde was added to 99 mL of deionized water and stirred to obtain a glutaraldehyde solution as a crosslinking agent for use; 10 g of gelatin solution was added to 90 mL of deionized water, stirred in a 50°C water bath for 1 h and ultrasonic to obtain a gelatin solution for use.

[0050] (2) Preparation of chitosan aerogel skeleton: The process flow of preparing chitosan aerogel skeleton by ice template method is as shown in Figure 1 The chitosan solution was injected into a mold composed of a copper sheet, a glass sheet and silica gel, and the mold had a length, width and height of 40 mm, 10 mm and 1 mm, respectively. The mold was placed on a pre-cooled freezing device, and the temperature was set to -90°C, with the copper sheet side close to the cold source. The temperature formed directional conduction from the copper sheet upwards, and the chitosan solution formed an ice block with anisotropic structure. After the sample was completely frozen, it was demolded and freeze-dried, and the freeze-dried sample was immersed in 0.4% sodium hydroxide ethanol solution for 30 min to remove glacial acetic acid. Then the sample was immersed in deionized water for 3 h, and the deionized water was replaced constantly to dilute and remove sodium hydroxide in the sample. Finally, the sample was freeze-dried again to obtain an anisotropic chitosan aerogel skeleton.

[0051] (3) Preparation of chitosan-gelatin composite hydrogel actuator: The gelatin solution was added to the chitosan aerogel skeleton and placed in a 4°C environment. To ensure that the gelatin solution is fully added to the aerogel skeleton, the chitosan aerogel skeleton was immersed in the gelatin solution and placed in a freeze dryer for vacuum treatment. During the vacuum process, the gas in the aerogel skeleton is sucked out, and the gelatin solution fully enters the aerogel skeleton under the action of gas pressure. Gelatin forms a network structure at low temperature, which is unstable, and heating will accelerate the molecular chain movement and make it liquefy again. To increase the stability, after the gelatin is gelled, the sample is immersed in 1% glutaraldehyde for 8 h to make the gelatin chemically crosslinked, and the molecular chain forms a stable network structure, making the gelatin hydrogel more stable. Finally, the sample was taken out to obtain a chitosan-gelatin composite hydrogel actuator.

[0052] (4) Multi-ion solution response: Sodium carbonate solution, sodium thiosulfate solution, sodium dihydrogen phosphate solution and sodium chloride solution were used for multi-ion solution response. As shown inFigure 6 a-c and Figure 7 As shown, the driving speed and the maximum bending angle of the composite actuator in different ionic solutions comply with Hofmeister sequence law. In addition, ethanol, acetone and some organic solvents containing a large number of hydroxyl and carbon groups can also reduce the dielectric constant of the solvent by forming hydrogen bonds with the protein, increase the attraction of opposite charges, and cause the protein to be salting out and denatured. As shown in Figure 6 d-f and Figure 8 As shown, the composite actuator has a response in dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA), ethylene glycol (EG), acetone (TATP), ethanol (ETOH) solvents, and completes the corresponding bending and recovery deformation. The composite actuator has good adaptability to changing environments.

[0053] The above examples are used to explain the present application, but are not limited to the present application. Any modifications and changes made to the present application within the spirit of the present application and the protection scope of the claims fall within the protection scope of the present application.

Claims

1. A method for preparing an anisotropic aerogel-induced gelatin hydrogel driver, comprising the following steps: (1) Preparation of raw materials: chitosan and glacial acetic acid are added to deionized water, stirred at room temperature to obtain a chitosan solution, and then ultrasonic is used to remove water bubbles for use; glutaraldehyde is added to deionized water and stirred to obtain a glutaraldehyde solution as a crosslinking agent for use; a gelatin solution is added to deionized water, stirred in a water bath, and then ultrasonic is used to obtain a gelatin solution for use; (2) Preparation of a chitosan aerogel skeleton: the chitosan solution is injected into a mold, and then the mold is placed on a pre-cooled freezing device, which is set to a temperature of -30 to -90℃, and the freezing time is 1 to 3 hours. The bottom end of the mold is close to the cold source, and the temperature forms a directional conduction from the bottom end upwards, so that the chitosan solution forms an ice block with an anisotropic structure. After the sample is completely frozen, it is demolded and freeze-dried. The freeze-dried sample is soaked in a sodium hydroxide ethanol solution to remove glacial acetic acid. Then the sample is soaked in deionized water to dilute the sodium hydroxide in the sample. Finally, the sample is freeze-dried again to obtain an anisotropic chitosan aerogel skeleton; (3) Preparation of a chitosan-gelatin composite hydrogel driver: the gelatin solution is added to the chitosan aerogel skeleton and placed in a 4℃ environment. To ensure that the gelatin solution is fully added to the aerogel skeleton, the chitosan aerogel skeleton is soaked in the gelatin solution and placed in a freeze dryer for vacuum treatment. During the vacuum process, the gas in the aerogel skeleton is sucked out, and the gelatin solution fully enters the aerogel skeleton under the action of air pressure. The gelatin forms a reticular structure at low temperature, which is unstable and will liquefy again when heated. To increase the stability, the sample is soaked in glutaraldehyde after gelatinization to chemically crosslink the gelatin, so that the molecular chains form a stable reticular structure, making the gelatin hydrogel more stable. Finally, the sample is taken out to obtain a chitosan-gelatin composite hydrogel driver.

2. The method of claim 1, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The concentration of the chitosan solution in step (1) is 1 to 3%, and the stirring time is 6 to 8 hours.

3. The method of claim 2, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The concentration of the glutaraldehyde solution in step (1) is 0.5 to 1.5%, and the stirring time is 20 to 50 minutes.

4. The method of claim 3, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The concentration of the gelatin hydrogel in step (1) is 5 to 20%, the water bath temperature is 45 to 60℃, and the stirring time is 1 to 2 hours.

5. The method of claim 1, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The mold in step (2) is composed of a copper sheet, a glass sheet, and silica gel, with a length of 40 mm, a width of 10 mm, and a height of 1 mm.

6. The method of claim 1, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The concentration of the sodium hydroxide ethanol solution in step (2) is 0.4%, and the soaking time is 30 to 60 minutes.

7. The method of claim 2, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The sample soaked in the sodium hydroxide ethanol solution in step (2) is soaked in deionized water for 3 hours, during which the deionized water needs to be replaced constantly to dilute and remove the sodium hydroxide in the sample.

8. The method of claim 1, wherein the anisotropic aerogel-induced gelatin hydrogel actuator is prepared by the steps of: The sample is soaked in glutaraldehyde for 6 to 12 hours in step (3).

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