Preparation method of three-dimensional force sensor based on programmable modulus controlled buckling forming

Abstract

The present invention belongs to the field of mechanical sensors, and provides a method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding. The method uses a grayscale programming polymer film as a base material, realizes a simple composite with a sensing material in a two-dimensional plane state, and realizes programmable regulation of the spatial distribution of the Young's modulus of the composite film through grayscale exposure technology. Then, based on the buckling molding technology, the composite film is transformed into a pre-designed three-dimensional structure, and the polymer is completely photocured through post-exposure processing to realize the independent existence and long-term stability of the three-dimensional structure of the sensor. The method of the present invention not only improves the preparation accuracy and controllability of the three-dimensional force sensor, but also enhances the structural stability of the sensor through post-processing steps, bringing new technical breakthroughs to the fields of flexible electronics and intelligent sensing.

Description

Technical Field

[0001] The invention belongs to the field of mechanical sensors, and in particular relates to a method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling forming. Background Art

[0002] Flexible force sensors play a key role in many fields such as robotics, medical health testing, and flexible electronics because of their sensing capabilities that mimic human touch. These sensors are usually planar structures that use advanced flexible materials as substrates, such as silicone rubber, polyimide, or polydimethylsiloxane, and are combined with functional materials such as carbon-based materials, metal nanowires, or conductive polymers to achieve high-sensitivity detection of pressure. With the development of technology, the design of sensors with three-dimensional structures has become an effective strategy to improve sensor performance. By increasing the surface area and complex geometric configurations, they not only improve the sensitivity of the sensor, but also give the sensor more accurate spatial pressure mapping and dynamic pressure tracking, thus showing strong application potential in scenarios such as the fine movements of robot dexterous hands, human physiological signal monitoring, and virtual reality interaction.

[0003] The combination of three-dimensional structure and functional materials is the key to realize highly sensitive three-dimensional force sensors. Buckling forming technology, as a clever manufacturing method, uses the principle of mechanics to transform the two-dimensional film structure into a three-dimensional form through buckling deformation. Starting from the easy-to-operate two-dimensional planar structure, this method not only simplifies the combination process with functional materials, reduces the complexity and cost of manufacturing, but also improves the compatibility of three-dimensional structures and materials, making it easy to integrate a variety of functional materials such as piezoelectric materials, conductive polymers, carbon nanotubes, graphene, etc., thereby enhancing the sensing performance of the sensor.

[0004] However, due to the processing characteristics of buckling forming technology, there are still great challenges in achieving three-dimensional structures with controllable shapes and maintaining the shape of three-dimensional structures. First, the control of shape during buckling forming is usually complicated, because the buckling behavior under mechanical action is affected by many factors, including material properties, thickness, and external loading conditions. Slight changes in these factors may cause the final shape to deviate from the expected design. Secondly, it is also difficult to maintain the three-dimensional structure independently. Since the buckled shape is difficult to maintain without continuous external force, additional fixing or supporting structures are required to ensure the long-term stability and reliability of the sensor. In addition, buckling forming technology also requires accurate mechanical models and control strategies to predict and optimize the buckling process, which further increases the difficulty of design and manufacturing. Despite these difficulties and challenges, buckling forming technology still has great potential in the preparation of three-dimensional structures with functional materials. Through continuous research and optimization, it is expected to overcome these challenges and achieve higher performance three-dimensional force sensors.

[0005] At present, the main way to achieve controllable buckling is to control the stiffness distribution of two-dimensional structures to achieve shape adjustment. For example, Fan et al. (Advanced Materials.2020, 32, 1908424) used 3D printing technology to produce a two-dimensional precursor with a spatial thickness distribution, so that different positions of the two-dimensional precursor have different bending stiffness. Under the action of compression displacement, due to the difference in stiffness in each region, different buckling deformations are produced, thereby achieving shape control of the structure of the three-dimensional surface; Chen et al. (Science.2023, 379, 1225–1232) developed a microlattice design strategy, which controls the porosity of the microlattice through photolithography technology, and then adjusts the stiffness distribution of the two-dimensional structure to achieve controllable shape changes during buckling. Although 3D printing or photolithography technology can achieve stiffness design of two-dimensional structures, its processing process is relatively complicated, and the uneven structural stiffness distribution may affect the mechanical properties of the final three-dimensional structure.

[0006] In addition, since the three-dimensional structure of the controllable buckling process is assembled under the action of the buckling force, after being separated from the substrate, the three-dimensional structure is difficult to maintain due to the loss of the buckling force. At the same time, this three-dimensional structure processed by the film itself has high flexibility and is prone to deformation when subjected to external forces. Therefore, the shape retention of the three-dimensional structure is one of the key issues affecting its effective application. Han et al. (Science Robotics. 2022, 7, 0602) fixed the three-dimensional structure by depositing silicon dioxide on the three-dimensional structure, so that it can be separated from the substrate to achieve an independent three-dimensional structure, but additional processing steps are required; Patent CN 113727530 A uses the shape fixing effect of shape memory polymers to enable the three-dimensional structure to be separated from the substrate and maintain the three-dimensional structure. However, since the initial state of the shape memory polymer is a two-dimensional planar structure, when it is separated from the substrate, the shape recovery effect is triggered by heat, and it can only be restored to the initial planar state, and the shape recovery of the independent three-dimensional structure cannot be achieved.

[0007] In summary, although buckling molding technology has significant advantages in preparing three-dimensional force sensors compatible with functional materials, the precise control of its molding process and the stable maintenance of the three-dimensional structure are still problems and challenges that need to be solved. Summary of the invention

[0008] The present invention aims to propose an innovative method for preparing a flexible three-dimensional force sensor, which is based on controllable buckling forming technology, uses a grayscale programming polymer film as a substrate material, and combines functional materials as the sensor element of the sensor. The spatial distribution of the Young's modulus of the film is programmably controlled by grayscale exposure technology. This uneven modulus distribution provides conditions for forming a variety of three-dimensional shapes during the buckling forming process. Using finite element simulation technology, the specific three-dimensional configuration formed by different modulus distributions can be accurately calculated and predicted, thereby achieving precise control of the buckling formed three-dimensional structure. After the buckling forming step, the formed three-dimensional structure is further subjected to post-exposure treatment to promote the complete cross-linking of the grayscale programming polymer film, thereby ensuring the independent existence and long-term stability of the three-dimensional structure. This method not only improves the preparation accuracy and controllability of the three-dimensional force sensor, but also enhances the stability of the sensor structure through the post-processing step, bringing new technological breakthroughs to the fields of flexible electronics and intelligent sensing.

[0009] To achieve the above object, the present invention proposes a method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling forming, the method comprising the following steps:

[0010] (1) Preparing a grayscale programming polymer film: mixing an amine curing agent, glycidyl methacrylate, epoxy resin and a photoinitiator, heating and stirring the mixture until uniform, and then pouring the mixture into a film mold, and curing the mixture to obtain a grayscale programming polymer film;

[0011] (2) Compounding the sensing material with the grayscale programming polymer film to obtain a composite film;

[0012] (3) Designing a two-dimensional planar structure of the force sensor and a mask pattern for grayscale exposure according to the required three-dimensional structure of the force sensor;

[0013] (4) using a laser cutting machine to process the two-dimensional planar structure designed in step (3) on the composite film obtained in step (2);

[0014] (5) placing the two-dimensional planar structure obtained in step (4) on a grayscale exposure platform, loading the mask pattern for grayscale exposure designed in step (3) as a mask, and performing grayscale exposure on the two-dimensional planar structure to produce a pre-designed Young's modulus distribution;

[0015] (6) Fixing the two-dimensional planar structure after grayscale exposure on the buckling assembly platform, applying force through the buckling assembly platform to cause the two-dimensional planar structure to buckle and deform, and accurately transforming it into a pre-designed three-dimensional structure under a specific Young's modulus distribution;

[0016] (7) Post-exposure the obtained three-dimensional structure on the buckling assembly platform of step (6), and then separate the three-dimensional structure from the buckling assembly platform to obtain a three-dimensional force sensor that can exist independently and be stable for a long time. Use wires to connect the sensing material of the prepared three-dimensional force sensor to the signal detection device.

[0017] Preferably, the grayscale programming polymer film in step (1) can be a product obtained by heating, mixing and curing polyetheramine curing agent D230, glycidyl methacrylate, epoxy resin E44 and photoinitiator UV-819.

[0018] Preferably, the film mold in step (1) can be a polytetrafluoroethylene mold.

[0019] Preferably, the sensing material in step (2) can be a functional material with sensing capability such as piezoelectric material, metal nanomaterial, carbon material, etc. The sensing material can be prepared on the surface of the grayscale programming polymer film by deposition, spraying, screen printing, etc. using a pre-designed pattern as a mask; or the patterned sensing material can be directly processed on the surface of the grayscale programming polymer film by inkjet printing, 3D printing, etc., to obtain a composite film composed of the sensing material and the grayscale programming polymer film. The sensing material is set at the structural deformation when the three-dimensional structure is subjected to force.

[0020] Preferably, in step (3), the designed two-dimensional planar structure of the force sensor includes a bonding portion for fixing to the buckling assembly platform.

[0021] Preferably, in step (3), in the mask pattern designed for grayscale exposure, the two-dimensional plane structure is divided into N regions, where N is usually 3-20, and the larger the N value, the better the shape control effect. Each region is assigned a grayscale value of 0%-100%.

[0022] Preferably, in step (4), a carbon dioxide laser cutting machine is used, and the parameters are set as follows: laser power 10%; scanning line speed during laser cutting 10 mm / s; marking times 1 time.

[0023] Preferably, the grayscale exposure platform in step (5) can be composed of an ultraviolet plane light source and a black-and-white liquid crystal screen (LCD). The black-and-white LCD screen can display the mask pattern for grayscale exposure designed in step (3) through computer output, as a mask for programmable grayscale exposure; the ultraviolet plane light source can emit uniform ultraviolet light. The composite film is placed on the black-and-white LCD screen and aligned with the mask pattern displayed on the black-and-white LCD screen; the ultraviolet plane light source exposes the composite film through the black-and-white LCD screen. When the ultraviolet light passes through different grayscale areas of the mask pattern on the black-and-white LCD screen, the light intensity will be attenuated to different degrees, so that different positions of the composite film will undergo different degrees of photocuring reactions, thereby obtaining a composite film with different Young's modulus distributions. The power of the ultraviolet plane light source is 60W and the wavelength is 405nm. The distance between the LCD screen and the ultraviolet plane light source is adjusted to 2 cm to the most uniform illumination. The exposure time is set to 1-3min.

[0024] Preferably, the buckling assembly platform in step (6) is a four-axis stretching platform, the PDMS film is pre-stretched, and then the bonding part of the two-dimensional planar structure is bonded to the pre-stretched PDMS film, and then the pre-stretching amount of the PDMS film is released, and the buckling assembly process is completed. The buckling degree of the buckling-molded three-dimensional structure can be controlled by controlling the pre-stretching amount of the PDMS film, and the pre-stretching amount of the PDMS film is generally selected to be 10%-30%.

[0025] Preferably, the post-exposure treatment in step (7) is to use an ultraviolet lamp to irradiate the three-dimensional structure, so that it is completely photocured and a new photocured cross-linked network is generated under the three-dimensional structure, so that it can still maintain the three-dimensional structure after leaving the buckling assembly platform and enhance its mechanical properties. The power of the ultraviolet lamp is 18W, the wavelength is 405nm, and the irradiation time is 5min.

[0026] The three-dimensional force sensor prepared by the present invention is a flexible structure. When subjected to pressure, the sensor structure will deform, and the attached sensing material will produce relevant signal change output, such as metal nanomaterials and carbon materials produce resistance changes, piezoelectric materials produce voltage changes, etc. Since the deformation parts of the three-dimensional structure are inconsistent when subjected to forces in different directions, the direction of the force can be determined. By calibrating the flexible three-dimensional force sensor in advance, the mapping relationship between the signal output and the force size is determined, and the size of the three-dimensional force can be determined by detecting the signal change. Therefore, when the three-dimensional force sensor is subjected to pressure, by detecting the signal changes in different parts, the size and direction of the three-dimensional force applied to the sensor can be accurately identified.

[0027] The present invention provides a method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling forming. By designing a grayscale exposure pattern, the Young's modulus distribution of a two-dimensional planar structure is controlled to achieve precise buckling shape control and obtain an independent three-dimensional structure with mechanical stability. The three-dimensional force sensor prepared by this technology has the following beneficial effects:

[0028] 1. Grayscale exposure is used to achieve precise control of the forming process of various three-dimensional structures, and the performance and sensitivity of the sensor can be flexibly adjusted according to specific application requirements.

[0029] 2. The post-exposure processing step increases the overall modulus of the three-dimensional structure, allowing it to exist independently from the assembly platform and significantly enhancing the mechanical stability of the sensor structure.

[0030] 3. The composite process of programmable modulus polymer film and sensing material is simplified, the material compatibility of three-dimensional force sensors is improved, and a simple and low-cost processing method is provided for the preparation of three-dimensional force sensors with customizable sensing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention provides a flow chart of a method for preparing a three-dimensional force sensor based on programmable modulus-controlled buckling molding, wherein the numbers in the figure are: 1 is a PET mask; 2 is a grayscale-programmed polymer film; 3 is a spray gun equipped with a sensing material; 4 is a composite film; 5 is a carbon dioxide laser; 6 is a two-dimensional planar structure; 7 is a black-and-white LCD screen; 8 is a planar ultraviolet light source; 9 is a buckling assembly platform; 10 is a pre-stretched PDMS film; 11 is a three-dimensional structure after buckling assembly; 12 is an ultraviolet lamp; and 13 is a three-dimensional force sensor.

[0032] Figure 2 It is the change of Young's modulus after the grayscale programming polymer film provided in Example 1 is exposed to different grayscales (0-100%) for 1 minute.

[0033] Figure 3 It is a stress-strain curve of the grayscale programmed polymer film provided in Example 1 after being exposed to different grayscales (0-100%) for 1 minute.

[0034] Figure 4 It is a schematic diagram of the dimensions of the two-dimensional planar structure designed in Example 1.

[0035] Figure 5 (A) and (B) are two mask patterns for grayscale exposure provided in Example 1.

[0036] Figure 6 (A) and (B) are height contour maps of shape simulation results of two different three-dimensional structures achieved by two different mask patterns in Example 1.

[0037] Figure 7 This is a schematic diagram of packaging the sensor in the 3D printed sensor frame in Example 1.

[0038] Figure 8 This is a physical picture of the three-dimensional force sensor obtained in Example 1.

[0039] Fig. 9 This is a sensor output signal diagram when the sensor 1 is continuously tapped with a finger in Example 1. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding provided by the present invention is used to prepare a flexible three-dimensional force sensor using silver nanowires as a sensing material, such as Figure 1 As shown, a patterned sensing material is prepared as a composite film on a grayscale programming polymer film, a mask pattern for grayscale exposure is loaded for exposure to produce a customized Young's modulus distribution, and a two-dimensional structure is converted into a three-dimensional structure through a buckling assembly platform and post-exposure is performed, specifically including the following steps:

[0043] (1) Preparation of grayscale programming polymer film: First, 1.42 g of glycidyl methacrylate and 1.15 g of polyetheramine D230 were mixed, heated to 50 °C using a magnetic stirring platform and stirred for 30 min. Then, 2.27 g of epoxy resin E44 and 0.5 g of photoinitiator UV-819 were added, heated to 70 °C and stirred for 50 min. Subsequently, the mixture was placed in a vacuum drying oven to remove bubbles, and finally poured into a film mold and allowed to cure for 3 days to obtain a grayscale programming polymer film with a thickness of 200 μm.

[0044] In order to test the mechanical properties of the grayscale programmed polymer film, the film was cut into several strips of 40 mm in length and 5 mm in width using laser processing as test samples, and divided into two groups for mechanical property testing. One group was exposed to 0%-100% grayscale for 1 minute, and a universal testing machine was used to test the change in Young's modulus of the grayscale programmed polymer film after different grayscale exposures ( Figure 2 ) and stress-strain curve ( Figure 3). As can be seen from the figure, the Young's modulus of the film under different grayscale exposure conditions is different. As the grayscale value of the grayscale exposure platform decreases (corresponding to the increase in light intensity), the Young's modulus of the material gradually increases from 10Mpa to 400Mpa, and the tensile properties gradually decrease from 250% to 150%. Another group of samples was directly post-exposure treated, using an 18W ultraviolet lamp for 5 minutes to allow the samples to undergo a complete photocuring reaction. The universal testing machine tested its Young's modulus to be 1400Mpa and the tensile properties to be 15%. The Young's modulus of the film was greatly improved after post-exposure, indicating that post-exposure treatment has a significant effect on strengthening the mechanical properties of grayscale programming polymers.

[0045] (2) A 20 μm thick PET film was processed into a hollow PET mask using laser processing. The PET mask was then placed close to the surface of a grayscale-programmed polymer film. 0.5 mL of an 8 mg / mL silver nanowire solution was sprayed on the patterned structure of the mask using a spray gun to form a sensing layer. The PET mask was then peeled off to obtain a composite film.

[0046] (3) Design the two-dimensional plane structure of the force sensor according to the target three-dimensional structure of the required force sensor. Its geometric dimensions are as follows: Figure 4 As shown. The four band structures of the two-dimensional plane structure are divided into four regions according to Figure 2 The obtained results of Young's modulus changes under different grayscale exposures are used to assign different grayscale programming to each area. Through grayscale exposure, programmable control of the Young's modulus of the two-dimensional planar structure is achieved. The mask pattern 1 used for grayscale exposure is as follows: Figure 5 As shown in (A), the mask pattern 2 used for grayscale exposure is as follows Figure 5 As shown in (B), the three-dimensional structural force sensors prepared in this way are sensor 1 and sensor 2 respectively.

[0047] (4) Using a carbon dioxide laser, a two-dimensional planar structure designed in step (3) is processed on the composite film obtained in step (2). The specific parameters of the laser cutting process are as follows: laser power 10%; scanning line speed during laser cutting 10 mm / s; marking times 1 time.

[0048] (5) A grayscale exposure platform (composed of a 60W ultraviolet light plane light source with a wavelength of 405nm and a black-and-white LCD screen) is set up. The mask pattern for grayscale exposure designed in step (3) is loaded on the black-and-white LCD screen as a mask. The two-dimensional planar structure obtained in step (4) is placed on the black-and-white LCD screen and aligned with the mask pattern displayed on the black-and-white LCD screen. The two-dimensional planar structure is grayscale exposed for 1 minute using an ultraviolet light plane light source through different grayscale areas of the mask pattern on the black-and-white LCD screen to produce a corresponding Young's modulus distribution.

[0049] (6) A four-axis stretching platform is used as a buckling assembly platform. The PDMS film is fixed on the platform and pre-stretched to 15%. Then, the bonding part of the two-dimensional planar structure after grayscale exposure is bonded to the pre-stretched PDMS film through a 20-μm thick double-sided tape. The stretching amount of the pre-stretched PDMS film on the buckling assembly platform is released, so that the bonding part of the two-dimensional planar structure is displaced, and the two-dimensional precursor is buckled to achieve a two-dimensional to three-dimensional structural transformation. The three-dimensional structural simulation shapes of sensor 1 and sensor 2 are as follows: Figure 6 (A) and Figure 6 (B) shown.

[0050] (7) Use an ultraviolet lamp with a power of 18W and a wavelength of 405nm to post-expose the three-dimensional structure on the buckling assembly platform for 5 minutes to completely photo-cure it, fix the current three-dimensional structure, and improve the mechanical properties of the structure. Then, the three-dimensional structure is separated from the buckling assembly platform to obtain a three-dimensional force sensor with an independent and stable structure. Place it on a 3D printed sensor frame (such as Figure 7 The sensor 1 is packaged in a plastic package and connected to the sensing material with a wire. Figure 8 shown.

[0051] (8) Use your finger to continuously tap the sensor, and the sensor signal output is as follows Fig. 9 As shown, it means that the sensor can sensitively sense the continuous tapping action of the finger.

[0052] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art will easily understand that the above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling forming, characterized in that: The steps include: (1) Preparing a grayscale programming polymer film: mixing an amine curing agent, glycidyl methacrylate, epoxy resin and a photoinitiator, heating and stirring the mixture until uniform, and then pouring the mixture into a film mold, and curing the mixture to obtain a grayscale programming polymer film; (2) Compounding the sensing material with the grayscale programming polymer film to obtain a composite film; (3) Designing a two-dimensional planar structure of the force sensor and a mask pattern for grayscale exposure according to the required three-dimensional structure of the force sensor; (4) using a laser cutting machine to process the two-dimensional planar structure designed in step (3) on the composite film obtained in step (2); (5) placing the two-dimensional planar structure obtained in step (4) on a grayscale exposure platform, loading the mask pattern for grayscale exposure designed in step (3) as a mask, and performing grayscale exposure on the two-dimensional planar structure to produce a pre-designed Young's modulus distribution; (6) Fixing the two-dimensional planar structure after grayscale exposure on a buckling assembly platform, applying force through the buckling assembly platform to cause the two-dimensional planar structure to buckle and deform, and transform it into a pre-designed three-dimensional structure under a specific Young's modulus distribution; (7) Post-exposure the obtained three-dimensional structure on the buckling assembly platform of step (6), and then separate the three-dimensional structure from the buckling assembly platform to obtain a three-dimensional force sensor with an independent and stable structure.

2. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The grayscale programming polymer film in step (1) is a product obtained by heating, mixing and curing polyetheramine curing agent D230, glycidyl methacrylate, epoxy resin E44 and photoinitiator UV-819.

3. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The sensing material in step (2) is a piezoelectric material, a metal nanomaterial or a carbon material.

4. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The sensing material in step (2) is arranged at the location where the three-dimensional structure is deformed when a force is applied thereto.

5. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: In step (3), the designed two-dimensional planar structure of the force sensor includes a bonding portion for fixing to the buckling assembly platform.

6. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: In step (3), in the mask pattern designed for grayscale exposure, the two-dimensional plane structure is divided into N regions, and each region is assigned a grayscale value of 0%-100%.

7. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: In step (4), a carbon dioxide laser cutting machine was used, and the parameters were set as follows: laser power 10%; scanning line speed during laser cutting 10 mm / s; marking times 1 time.

8. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The grayscale exposure platform in step (5) is composed of a planar ultraviolet light source and a black-and-white LCD screen; the black-and-white LCD screen displays the mask pattern for grayscale exposure designed in step (3); the composite film is placed on the black-and-white LCD screen and aligned with the mask pattern displayed on the black-and-white LCD screen; after the planar ultraviolet light source passes through different grayscale areas of the mask pattern on the black-and-white LCD screen, the composite film is exposed to produce a pre-designed Young's modulus distribution.

9. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The buckling assembly platform in step (6) is a four-axis stretching platform, which pre-stretches the PDMS film, then bonds the bonding parts of the two-dimensional planar structure to the pre-stretched PDMS film, and then releases the pre-stretching amount of the PDMS film, thus completing the buckling assembly process.

10. The method for preparing a three-dimensional force sensor based on programmable modulus controlled buckling molding according to claim 1, characterized in that: The post-exposure treatment in step (7) is to use ultraviolet light to irradiate the three-dimensional structure to generate a new photocurable cross-linked network under the three-dimensional structure.

11. A three-dimensional force sensor based on programmable modulus controlled buckling molding obtained by the preparation method according to any one of claims 1 to 10.

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