A method for fabricating a flexible actuator based on force-deformation synergistic regulation

Abstract

This invention discloses a method for fabricating a flexible actuator based on force-deformation synergistic regulation, belonging to the field of flexible robot technology with high output force and large deformation performance. Utilizing electric field alignment technology, carbon nanotubes are oriented along the electric field direction within a polymer. This oriented arrangement of carbon nanotubes not only improves the electrostrain of the composite material but also enhances its overall stiffness. Therefore, the force-deformation synergistic flexible actuator achieves both large deformation and high output force under a low driving electric field, solving the long-standing problem of polymer composite materials being flexible but not rigid. Based on this, the polymer composite film serving as the force-deformation synergistic flexible actuator is adhered to a support to obtain a climbing robot, which achieves climbing functionality on steep slopes. This invention is simple to operate and easy to implement, providing a new approach for fabricating high-performance flexible climbing robots and showing promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of flexible actuator technology, specifically relating to a method for preparing a flexible actuator based on force-deformation synergistic regulation. Background Technology

[0002] As a core component of flexible robots, actuators need to generate sufficient deformation to complete the required actions, such as grasping, supporting tools, and transporting objects. However, due to the conflict between large strain and high stiffness, achieving actuator materials that simultaneously possess large deformation and high output force is a significant challenge. Traditional actuator materials include ferroelectric ceramics, which can generate sufficient output force due to their high stiffness, but their small deformation severely limits their application in flexible robots.

[0003] Electroactive polymers, including typical polyvinylidene fluoride (PVDF)-based ferroelectric polymers and dielectric elastomers, possess advantages such as good flexibility, ultra-large electric field response strain, low density, simple manufacturing process, and low cost, showing great promise for applications in biomedicine, aerospace, and bionics. However, the high driving electric field of electroactive polymers is detrimental to their long-term reliability and safety during use. Although some studies (Chen, X. et al. Giantelectrostriction enabled by defect-induced critical phenomena in relaxorferroelectric polymers. Macromolecules 56, 690-696 (2023); Gong, H. et al. Tuning the ferroelectric phase transition of P(VDF-TrFE) through a simple approach of modification by introducing double bonds. ACS Omega 7, 42949–42959 (2022).) have achieved materials with large strain under low driving electric fields, the problem of low output force caused by extremely low modulus still exists. Therefore, to expand their application range, electroactive polymer actuators with large deformation must overcome their limitation of low output force; however, the generation of high output force often leads to a decrease in strain. Therefore, to date, there is no effective method to simultaneously achieve large deformation and high output force in electroactive polymer actuators. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for preparing a flexible actuator based on force-deformation synergistic regulation. By arranging nanoparticles in an electroactive polymer through an external field, the force-deformation synergistic enhancement effect of the flexible actuator is simultaneously achieved through microstructure design, thereby realizing large deformation and high output force of the electroactive polymer actuator.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for fabricating a flexible actuator based on force-deformation synergistic regulation, comprising:

[0007] An alumina insulating layer is uniformly grown on the surface of carbon nanotubes; the carbon nanotubes with the alumina insulating layer are uniformly dispersed in a polymer solution to obtain a carbon nanotube-polymer dispersion.

[0008] An electric field is applied, and under the action of the electric field, the carbon nanotubes in the carbon nanotube-polymer dispersion form an oriented arrangement in the dispersion along the direction of the electric field application. After drying, a polymer composite film with oriented carbon nanotubes is obtained, which is a flexible actuator with force-deformation synergy.

[0009] The concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.5% to 1.1%.

[0010] The solute in the polymer solution is polyvinylidene fluoride and its copolymers, including polyvinylidene fluoride (PVDF), polyvinyl fluoride-trifluoroethylene (P(VDF-TrFE)), polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene (P(VDF-TrFE-CFE)) and polyvinylidene fluoride-trifluoroethylene-trifluorochloroethylene (P(VDF-TrFE-CTFE)), and the solvent is N,N-dimethylformamide.

[0011] The thickness of the alumina insulating layer is 5–10 nm.

[0012] The method for preparing the carbon nanotube-polymer dispersion is as follows: carbon nanotubes with an alumina insulating layer are uniformly dispersed in a polymer solution and ultrasonically vibrated for 2-5 hours under ice-water bath conditions to obtain the carbon nanotube-polymer dispersion.

[0013] The specific steps for forming the oriented alignment of carbon nanotubes are as follows: At a temperature of 60–70°C, an electric field parallel to the predetermined alignment direction is applied, with a field strength of 100–400 V. pp / mm, for 20–40 minutes.

[0014] The concentration of the polyvinylidene fluoride and its copolymers is 8% to 12%.

[0015] A force-deformation coordinated flexible actuator is prepared based on the method described above.

[0016] A climbing robot is assembled by using a force-deformation coordinated flexible actuator as the driving force for the climbing robot.

[0017] The main structure of the climbing robot is made of flexible polymer film, including polyimide (PI), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0018] The assembly method of the climbing robot includes: taking a polymer composite film with a length of 2-7 cm, a width of 1-4 cm, and a thickness of 18-22 micrometers as a flexible actuator for force-deformation coordination, sputtering 100 nm thick silver electrodes on both sides of the film, and leading out the electrodes through silver tape; then attaching the polymer composite film to a support film with a length of 4-6 cm, a width of 2-7 cm, and a thickness of 0.5-2.5 mm using double-sided adhesive.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention utilizes electric field alignment technology to orient carbon nanotubes in the dispersion of polymer along the direction of electric field. Oriented carbon nanotubes can improve the electro-strain of polymer composites under low driving electric field.

[0021] (2) The present invention utilizes electric field alignment technology to orient carbon nanotubes in the dispersion of polymer along the direction of electric field. The oriented carbon nanotubes can improve the overall stiffness of polymer composite material, enabling the polymer composite material actuator to achieve high output force under low driving electric field.

[0022] (3) The force-deformation coordinated flexible actuator of the present invention realizes large deformation and high output force simultaneously, and can be successfully applied to a climbing robot to realize its climbing function on steep slopes (up to 52°).

[0023] In summary, this invention, by controlling the arrangement of carbon nanotubes in a composite material, enables a force-deformation synergistic flexible actuator to simultaneously achieve large deformation and high output force under a relatively low electric field, solving the long-standing problem of polymer composite actuators being flexible but not rigid. Thanks to the high output force of the force-deformation synergistic flexible actuator, the climbing robot successfully achieved climbing functionality on steep slopes. This invention is simple to operate and easy to implement, providing a new approach for fabricating high-performance flexible actuators and expanding their practical applications in flexible robotics, and has promising application prospects. Attached Figure Description

[0024] Figure 1This is a schematic diagram illustrating the preparation of the composite material film containing oriented nanoparticles in the examples;

[0025] Figure 2 Electrostrain of the polymer composites in Example 4 and the comparative example under different electric fields;

[0026] Figure 3 The output force of the polymer composite material under different electric fields in Example 4 and the comparative example;

[0027] Figure 4 The climbing robot in Example 4 and the comparative example demonstrates its climbing function on a steep slope (52°). Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] Example 1: Refer to Figure 1 A method for fabricating a flexible actuator based on force-deformation synergistic regulation, comprising:

[0031] A uniform and dense alumina insulating layer with a thickness of 10 nm was grown on the surface of carbon nanotubes using atomic layer deposition technology. A dispersion of carbon nanotubes-polymer was prepared with a carbon nanotube concentration of 0.5%. Specifically, the carbon nanotubes with the deposited alumina insulating layer were dispersed in a 12% P(VDF-TrFE-CTFE) polymer solution and ultrasonically vibrated for 2 hours under ice-water bath conditions to obtain a uniformly dispersed suspension.

[0032] A dispersion containing carbon nanotubes was uniformly coated onto a glass plate using a coating method, and then subjected to a temperature of 60°C and an induction temperature of 100°C. pp Under an electric field of / mm, carbon nanotubes in the dispersion were oriented and aligned for 40 min. The mixture was then placed in an oven at 130℃ for 2 hours to obtain a polymer composite film with oriented carbon nanotubes, thus obtaining a flexible actuator with force-deformation synergy.

[0033] A climbing robot is assembled using a force-deformation coordinated flexible actuator as its drive. The assembly method includes: taking a polymer composite film with a length of 4 cm, a width of 2 cm, and a thickness of 18 micrometers as the force-deformation coordinated flexible actuator, sputtering 100 nm thick silver electrodes on both sides of the film, and leading out the electrodes through silver tape; then attaching the polymer composite film to a support film with a length of 6 cm, a width of 4 cm, and a thickness of 0.5 mm using double-sided adhesive, and leading it out through silver tape to apply a driving electric field; finally, attaching it to the support with double-sided adhesive to assemble a simple climbing robot structure.

[0034] Example 2: The concentration of carbon nanotubes in the carbon nanotube-polymer dispersion was 1.1%, and the remaining operations were the same as in Example 1.

[0035] Example 3: The thickness of the alumina insulating layer on the carbon nanotube surface is 7.5 nm, and the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 1.1%; ultrasonic vibration is performed for 4 hours under ice-water bath conditions; and an electric field of 300 V is applied at a temperature of 70°C to the oriented alignment. pp / mm; The polymer composite membrane for the climbing robot is 7 cm long, 4 cm wide, and 22 micrometers thick, while the support membrane is 6 cm long, 7 cm wide, and 2.5 mm thick; the remaining operations are the same as in Example 1.

[0036] Example 4: The thickness of the alumina insulating layer on the carbon nanotube surface is 5 nm, and the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 1.1%; ultrasonic oscillation is performed for 5 hours under ice-water bath conditions; and an electric field of 300 V is applied at a temperature of 65°C to the oriented alignment. pp The polymer composite membrane for the climbing robot is 2 cm long, 1 cm wide, and 20 micrometers thick; the support membrane is 4 cm long, 2 cm wide, and 1 mm thick; the rest of the operation is the same as in Example 1.

[0037] Example 5: The thickness of the alumina insulating layer on the carbon nanotube surface is 7.5 nm, the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.8%, and the oriented electric field is 400 V. pp / mm, duration is 20min, the rest of the operation is the same as in Example 1.

[0038] Example 6: The thickness of the alumina insulating layer on the carbon nanotube surface is 5 nm, the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.8%, and the oriented electric field is 400 V. pp / mm, duration is 20min, the rest of the operation is the same as in Example 3.

[0039] Example 7: The thickness of the alumina insulating layer on the carbon nanotube surface is 5 nm, the concentration of carbon nanotubes in the carbon nanotube-polymer dispersion is 0.8%, and the electric field for directional alignment is 400 V. pp / mm, duration is 30min, the rest of the operation is the same as in Example 4.

[0040] Example 8: The polymer is PVDF, and the rest of the operation is the same as in Example 3.

[0041] Example 9: The polymer is P(VDF-TrFE), and the rest of the operation is the same as in Example 4.

[0042] Example 10: The polymer is P(VDF-TrFE-CFE), and the rest of the operation is the same as in Example 5.

[0043] Comparative Example 1:

[0044] a. Disperse 1g of polymer powder (PVDF or P(VDF-TrFE) or P(VDF-TrFE-CFE) or P(VDF-TrFE-CTFE)) into 10mL of N,N-dimethylformamide and stir for 10h to obtain a polymer solution.

[0045] b. The polymer solution is uniformly coated onto a glass plate using a scraping method, dried at 50-100℃, and then placed in an oven at 110-130℃ for 2-4 hours to obtain a polymer composite film.

[0046] c. Sputter silver electrodes of about 100 nm thickness on both sides of the polymer composite film, and lead them out with silver tape to apply a driving electric field. Then attach them to the support with double-sided adhesive to assemble a simple climbing robot.

[0047] Reference Figure 2 , Figure 2 The figures show the electrostrain test results of the polymer composites in Example 4 and the comparative example under different electric fields. The results indicate that the composite containing laterally aligned carbon nanotubes achieved higher electrostrain under the same electric field. (Refer to...) Figure 3 , Figure 3 The figures show the output force test results of the polymer composite materials in Example 4 and the comparative example under different electric fields. The results indicate that the laterally arranged carbon nanotubes significantly increase the output force of the composite membrane actuator and significantly reduce its driving electric field. (Refer to...) Figure 4 , Figure 4 The climbing robot in Example 4 and the comparative example demonstrates its climbing function on a steep slope (52°). The results show that the climbing robot can achieve the climbing function on steep slopes with a gradient of up to 52°.

[0048] As shown in the examples and comparative examples, the comparative examples, due to their smaller strain and output force, cannot achieve the climbing function on steep slopes. However, the examples utilize an electric field alignment method to obtain a polymer film actuator with large strain and large output force, successfully realizing the climbing robot's climbing function on steep slopes. The polymer dispersion is mainly achieved through stirring and ultrasonic oscillation; the polymer composite film is mainly prepared by a film-scraping method; and the directional alignment of carbon nanotubes within the composite material is mainly achieved through the modulation of the electric field after film scraping. By aligning the internal carbon nanotubes, the strain and output force of the composite material are increased simultaneously, ultimately successfully applying a force-deformation synergistic flexible actuator to a structurally simple flexible climbing robot. The advantages of this invention are that it can obtain a force-deformation synergistic flexible actuator with both large deformation and high output force, resulting in a high-performance flexible climbing robot. The use of the film-scraping method also facilitates the industrial production of thin films. The entire process is simple and easy to implement, and the assembled climbing robot has a simple structure. This provides a new approach for preparing flexible biomimetic robots adapted to different ground environments, with good application prospects and economic benefits.

[0049] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for fabricating a flexible actuator based on force-deformation synergistic regulation, characterized in that: Alumina insulating layer is uniformly grown on the surface of carbon nanotubes; Carbon nanotubes with an alumina insulating layer are uniformly dispersed in a polymer solution to obtain a carbon nanotube-polymer dispersion. An electric field is applied, and under the action of the electric field, the carbon nanotubes in the carbon nanotube-polymer dispersion form an oriented arrangement in the dispersion along the direction of the electric field application. After drying, a polymer composite film with oriented carbon nanotubes is obtained, which is a flexible actuator with force-deformation synergy. The concentration of carbon nanotubes in the carbon nanotube-polymer dispersion was 0.8%–1.1%. The solute in the polymer solution is polyvinylidene fluoride and its copolymers, including polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, polyvinylidene fluoride-trifluoroethylene-chlorofluoroethylene and polyvinylidene fluoride-trifluoroethylene-trifluorochloroethylene, and the solvent is N,N-dimethylformamide; The preparation method of carbon nanotube-polymer dispersion is as follows: carbon nanotubes with an alumina insulating layer are uniformly dispersed in a polymer solution and ultrasonically vibrated for 2-5 h under ice-water bath conditions to obtain carbon nanotube-polymer dispersion. The specific steps for forming the oriented alignment of carbon nanotubes are as follows: at a temperature of 60~70 °C, an electric field parallel to the predetermined alignment direction is applied, with an electric field strength of 300-400 V. pp / mm, for 20~40 min.

2. The method according to claim 1, characterized in that, The thickness of the alumina insulating layer is 5~10 nm.

3. The method according to claim 1, characterized in that, The concentration of polyvinylidene fluoride and its copolymers is 8% to 12%.

4. A force-deformation coordinated flexible actuator, characterized in that, Prepared based on the method described in any one of claims 1-3.

5. A hill-climbing robot, characterized in that: The force-deformation coordinated flexible actuator described in claim 4 is assembled as the drive for the climbing robot.

6. A climbing robot according to claim 5, characterized in that: The main structure of the climbing robot is made of flexible polymer film, including polyimide (PI), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

7. The assembly method of a hill-climbing robot according to claim 5, characterized in that: A polymer composite film with a length of 2-7 cm, a width of 1-4 cm, and a thickness of 18-22 μm is used as a flexible actuator for force-deformation coordination. 100 nm thick silver electrodes are sputtered on both sides of the film, and the electrodes are led out through silver tape. The polymer composite film is then attached to a support film with a length of 3-6 cm, a width of 2-7 cm, and a thickness of 0.5-2.5 mm using double-sided adhesive.

Images