Pressure-sensitive material layer, manufacturing method thereof, pressure sensor and electronic skin

Abstract

The invention relates to a pressure-sensitive material layer and a manufacturing method thereof, and a pressure sensor and electronic skin based on the pressure-sensitive material layer. According to the pressure-sensitive material layer, the plurality of truncated-cone-shaped bump structures are distributed on the base material layer in an array manner, so that the adjustability of the contact area is realized, the capacitance value change range is widened, and the pressure-sensitive performance is improved. The material layer adopts a hydrogel material formed by combining a high-molecular polymer (such as polyvinyl alcohol) and an electrolyte, and has good biocompatibility, skin-friendly property and universality. The boss structure in the shape of the circular truncated cone can better adapt to and disperse pressure, and uniform and stable pressure sensing is achieved. The manufacturing method adopts simple raw materials and steps, and is high in production efficiency, high in repeatability and suitable for large-scale production. The pressure sensor and the electronic skin have excellent sensing performance, stability and durability, and are suitable for the fields of medical electronic equipment, wearable equipment, human-computer interaction and the like.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a pressure-sensitive material layer, a manufacturing method thereof, a pressure sensor and electronic skin. Background Art

[0002] Flexible sensors are flexible and extensible. They can not only be bent or even folded freely, but also be flexibly arranged according to measurement conditions, which greatly broadens the application scenarios of sensors. In the fields of medical electronics, environmental monitoring, and wearable devices, the advantages of flexible sensors are particularly significant. Especially in terms of wearability, they can fit human skin better and achieve more accurate and comfortable health monitoring, because human skin itself is not completely flat.

[0003] Among many flexible materials, hydrogel has attracted much attention due to its excellent biocompatibility and skin-friendliness. Compared with traditional elastic materials such as PDMS and silicone rubber, hydrogel is safer during use and more friendly to the user's skin. Therefore, it is widely used in the manufacture of flexible sensors.

[0004] However, despite the many advances in flexible sensor technology, there are still some urgent problems to be solved in the field of capacitive pressure sensors. Traditional capacitive pressure sensors usually adopt a structure in which two sheets of sheet material overlap each other, separated by an insulating film in the middle. Although this structure meets the basic sensing needs to a certain extent, it limits the improvement of the capacitive pressure-sensitive performance. Especially in terms of pressure-sensitive changes, traditional designs often cannot achieve a large range of changes, which affects the sensitivity and accuracy of the sensor. In addition, the contact area of ​​the traditional structure is large and is easily disturbed by external environmental factors such as temperature and humidity, resulting in unstable sensor performance. This instability not only affects the accuracy and reliability of the sensor, but also limits its application in complex environments.

[0005] In view of the above problems, although the hydrogel materials in the prior art have shown certain potential in pressure sensing applications, their performance improvement space is still limited. Therefore, new designs and optimization schemes are needed to improve the pressure-sensitive performance of hydrogel sensors. Summary of the invention

[0006] The purpose of the present application is first to provide a pressure-sensitive material layer, which can greatly improve the pressure sensitivity, has good versatility, and can be widely used in different types of hydrogel sensors. The purpose of the present application is achieved through the following technical solution. The pressure-sensitive material layer includes a substrate layer and a bump structure on the substrate layer; The number of the bump structures is multiple, and the array is distributed on the substrate layer; The substrate layer and the bump structure are formed of a hydrogel material.

[0007] In one embodiment, the protrusion structure is a frustum.

[0008] In one embodiment, the hydrogel material includes a high molecular polymer and an electrolyte.

[0009] In one embodiment, the high molecular polymer is selected as polyvinyl alcohol, and the electrolyte is selected from one or more of AlCl3 (aluminum chloride), FeCl3 (ferric chloride), MgCl2 (magnesium chloride), ZnCl2 (zinc chloride), NaCl (sodium chloride), PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid)).

[0010] The present application further provides a pressure sensor, comprising: A first electrode layer, a first pressure-sensitive material layer, a second pressure-sensitive material layer, and a second electrode layer; The first pressure-sensitive material layer and the second pressure-sensitive material layer are the aforementioned pressure-sensitive material layers; The surface bump structures of the first pressure-sensitive material layer and the second pressure-sensitive material layer correspond to each other, the substrate layer in the first pressure-sensitive material layer is connected to the first electrode layer, and the substrate layer in the second pressure-sensitive material layer is connected to the second electrode layer.

[0011] In one embodiment, top surfaces of the bump structures abut against each other.

[0012] In one embodiment, an insulating film layer is further included between the first pressure-sensitive material layer and the second pressure-sensitive material layer.

[0013] In one embodiment, the first electrode layer further includes a first protective layer on the other side of the first pressure-sensitive material layer, and the second electrode layer further includes a second protective layer on the other side of the second pressure-sensitive material layer, and the first protective layer and the second protective layer are formed of the same hydrogel material as the pressure-sensitive material layer.

[0014] The present application further provides a method for manufacturing a pressure-sensitive material layer, comprising: preparing raw materials, the raw materials including high molecular polymer, conductive metal salt and solvent; Mixing the high molecular polymer with the solvent and fully dissolving them to obtain a first solution; Adding a conductive metal salt to the first solution, removing bubbles after mixing evenly, and pouring the obtained mixed solution into a mold having a truncated cone-shaped groove to obtain a hydrogel precursor; The hydrogel precursor is subjected to 1 to 5 cycles of freezing and thawing treatment to obtain a pressure-sensitive material layer.

[0015] In one embodiment, the freezing and thawing process cycle includes first cooling to a temperature within a range of -10°C to -30°C and freezing for 4 to 8 hours, and then placing at 15°C to 45°C for 0.5 to 2 hours.

[0016] In addition, the present application further provides an electronic skin, comprising the aforementioned pressure-sensitive material layer or the aforementioned pressure sensor.

[0017] Compared with the prior art, the present application has the following beneficial effects: the present application achieves a significant improvement in the pressure-sensitive performance of the capacitive pressure sensor by introducing a truncated cone-shaped hydrogel bump structure on the surface. Traditional capacitive pressure sensors are limited by structural design, with large contact areas and limited changes, which makes it difficult to improve the pressure-sensitive performance. The pressure-sensitive material layer of the present application, with its truncated cone-shaped bump structure, can significantly increase the contact area when subjected to pressure. After actual testing, the pressure sensor using the pressure-sensitive material layer of the present application can achieve a pressure-sensitive change of 60% to 50 times that of the traditional design, achieving a qualitative leap in pressure-sensitive performance and sensitivity. This performance improvement enables the sensor to perform well even when detecting small pressure changes.

[0018] The pressure-sensitive material layer and pressure sensor design of the present application have high versatility and applicability. The bump structure of the pressure-sensitive material layer is formed by a hydrogel material, which not only has good biocompatibility and skin affinity, but also has high plasticity. By adjusting the type and proportion of high molecular polymers (such as polyvinyl alcohol) and electrolytes, a pressure-sensitive material layer suitable for different application scenarios can be prepared. In addition, the pressure sensor of the present application has a simple structure, is easy to manufacture and integrate, and can be widely used in medical electronics, environmental monitoring, wearable devices and other fields.

[0019] In summary, this application successfully solves the problems existing in traditional capacitive pressure sensors by introducing a hydrogel bump structure with a truncated cone shape on the surface, achieving a significant improvement in pressure-sensitive performance and enhanced versatility. This design not only improves the sensitivity and accuracy of the sensor, but also broadens its scope of application, injecting new vitality into the development of flexible sensor technology. At the same time, the manufacturing method of this application is simple and feasible, easy to realize industrial production, and has broad market prospects and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a top view of a pressure-sensitive material layer in one embodiment of the present application; Figure 2 is a schematic diagram of the cross-sectional structure of a pressure-sensitive material layer in one embodiment of the present application; Figure 3 is a schematic diagram of a top view of a pressure-sensitive material layer in one embodiment of the present application; Figure 4is a schematic diagram of the cross-sectional structure of a pressure-sensitive material layer in one embodiment of the present application; Figure 5 is a schematic diagram of a top view of a pressure-sensitive material layer in one embodiment of the present application; Figure 6 is a schematic diagram of the cross-sectional structure of a pressure-sensitive material layer in one embodiment of the present application; Figure 7 is a schematic diagram of a top view of a pressure-sensitive material layer in one embodiment of the present application; Figure 8 is a schematic diagram of the cross-sectional structure of a pressure-sensitive material layer in one embodiment of the present application; Fig. 9 is a schematic diagram of a top view of a pressure-sensitive material layer in one embodiment of the present application; Fig.10 is a schematic diagram of the cross-sectional structure of a pressure-sensitive material layer in one embodiment of the present application; Fig.11 This is a schematic diagram of the working principle structure of a pressure-sensitive material layer in a pressure sensor in one embodiment of the present application; Fig.12 It is a schematic flow chart of a method for manufacturing a pressure-sensitive material layer in one embodiment of the present application.

[0021] Description of reference numerals: 100, substrate layer; 200, bump structure; 300, insulating film layer. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] Flexible sensor technology, with its unique flexibility and ductility, has shown great application potential in the fields of medical electronics, environmental monitoring, and wearable devices. In these fields, sensors need to be able to conform to complex surfaces, such as human skin, to achieve accurate and comfortable monitoring. However, traditional capacitive pressure sensors are often difficult to achieve high pressure-sensitive performance and versatility due to the limitations of their structural design. As a material with good biocompatibility and skin-friendliness, hydrogel has gradually become an ideal choice for the manufacture of flexible sensors. Hydrogel is not only soft and elastic, and can fit closely to human skin to reduce discomfort, but also can achieve capacitive pressure sensing through its internal electrolytes and polymers. Based on this background, the present application proposes a new pressure-sensitive material layer and its manufacturing method, as well as a pressure sensor and electronic skin based on this material layer. Next, the specific structure and manufacturing method of this pressure-sensitive material layer, as well as the design principles and performance characteristics of the pressure sensor and electronic skin based on this material layer will be introduced in detail. Please refer to Figures 1 to 3 As shown, a pressure-sensitive material layer in a preferred embodiment of the present application achieves adjustability of the contact area by distributing a plurality of truncated cone-shaped protrusion structures 200 in an array on a substrate layer 100, thereby being able to significantly increase the capacitance value and enhance the pressure-sensitive performance when subjected to pressure. The material layer also has good versatility and is suitable for the preparation and application of a variety of hydrogel materials.

[0026] The present application first provides a pressure-sensitive material layer, including a substrate layer 100 and a bump structure 200 on the substrate layer 100, wherein the bump structure 200 is multiple in number and distributed in an array on the substrate layer 100, and the substrate layer 100 and the bump structure 200 are formed by a hydrogel material. The pressure-sensitive material layer includes a substrate layer 100 and a bump structure 200. The substrate layer 100, as the basic structure of the material layer, provides a stable support for the entire structure, facilitates coordination with other structures, and fixes the bump structure 200. On this basis, a plurality of bump structures 200 are distributed in an array, which can keenly sense the pressure changes brought by the outside world at different positions. Both the substrate layer 100 and the bump structure 200 use advanced hydrogel materials as the main components. Through the array-distributed bump structure 200, the present application achieves the adjustability of the contact area. When external pressure acts on the pressure-sensitive material layer, the bump structure 200 can respond and transmit the pressure signal more effectively, thereby significantly improving the range of capacitance value variation, so that the sensor can more accurately capture and identify small pressure changes, greatly improving the sensitivity and response speed of the pressure-sensitive material. The use of hydrogel material as the main body of the substrate layer 100 and the bump structure 200 gives the pressure-sensitive material layer good biocompatibility and skin-friendliness, and also enables it to easily adapt to various complex application environments. Whether it is close-fitting monitoring of medical electronic equipment or comfortable wearing of wearable devices, the pressure-sensitive material layer of the present application can show adaptability and stability. The selection of hydrogel material not only simplifies the manufacturing process and reduces production costs, but also makes it easier to achieve precise size control and shape design of the pressure-sensitive material layer during the manufacturing process. It should be noted that the bump structure 200 in the present application refers to the part that has a protrusion relative to the bottom surface. The specific shape of the protrusion is not specifically limited. Structures such as a truncated cone and a sphere can be used as the bump structure 200 in the present application. Please refer to Figure 1-10 , Figure 1-10 Detailed description of the bump structure 200 is given in FIG.

[0027] Please read further Figure 1-2Specifically, the bump structure 200 is a truncated cone. The bump structure 200 in the present application is designed to be in the shape of a truncated cone, with a smaller upper bottom surface and a larger lower bottom surface, forming a natural slope. Such a design enables the bump structure 200 to better adapt to and disperse the pressure when subjected to external pressure, thereby achieving a more uniform and stable pressure sensing effect. When subjected to pressure, the truncated cone-shaped bump structure 200 can use its slope to gradually disperse the pressure to a wider area, which can avoid sensing distortion or damage caused by excessive local pressure, so that the pressure-sensitive material layer can still maintain stable sensing performance when subjected to greater pressure. Since the truncated cone-shaped bump structure 200 has a smaller initial contact area, when external pressure acts on it, the contact area will increase rapidly, thereby meeting the requirement of inducing a more significant change in capacitance value. This feature enables the pressure-sensitive material layer to more sensitively capture and respond to small pressure changes, improves the sensitivity and response speed of the sensor, and can also expand the pressure range. The truncated cone-shaped bump structure 200 is more structurally robust and can withstand greater deformation without being easily damaged. This design not only prolongs the service life of the pressure-sensitive material layer, but also improves its stability and reliability in complex application environments.

[0028] Attached Figure 3-4 The bump structure 200 in the technical solution of the corresponding embodiment is a cubic structure, which is simple to manufacture and has a larger contact area. Figure 5-6 The bump structure 200 in the technical solution of the corresponding embodiment is spherical, and small bumps are further formed on the sphere. This arrangement can better improve the sensitivity of the initial deformation detection. Figure 7-8 The bump structure 200 in the corresponding embodiment is conical. Figure 9-10 The bump structure 200 in the technical solution of the corresponding embodiment is an irregular shape, and these specific shapes have their own deformation characteristics, which can adjust the accuracy of detection under different pressing situations.

[0029] Specifically, the hydrogel material includes a polymer and an electrolyte. The hydrogel material in the present application adopts a formula combining a polymer and an electrolyte. The polymer serves as the skeleton structure of the hydrogel, providing the necessary mechanical strength and stability, and the electrolyte serves as a conductive medium, giving the hydrogel material good hydrogel properties. The combination of the polymer and the electrolyte not only makes the hydrogel material soft and elastic, but also has excellent biocompatibility. The combination of the polymer and the electrolyte enables the hydrogel material to respond quickly and produce a significant change in capacitance when subjected to external pressure. This change is closely related to the size and distribution of the pressure, thereby achieving accurate measurement and sensing of the pressure. The selection of the polymer and the electrolyte takes into account the biocompatibility and skin-friendliness of the material, so that the hydrogel material has a wide range of application prospects in the fields of medical electronic equipment, wearable devices, etc. that are in direct contact with the human body. At the same time, good biocompatibility also ensures the safety and comfort of the material during use.

[0030] Specifically, the high molecular polymer is selected as polyvinyl alcohol, and the electrolyte is selected from one or more of AlCl3 (aluminum chloride), FeCl3 (ferric chloride), MgCl2 (magnesium chloride), ZnCl2 (zinc chloride), NaCl (sodium chloride), PEDOT:PSS (poly (3,4-ethylenedioxythiophene) - poly (styrene sulfonic acid)). Polyvinyl alcohol provides structural support for hydrogel materials with its film-forming property, water resistance and biocompatibility. The combination of polyvinyl alcohol and electrolyte enables the hydrogel material to quickly produce a significant change in capacitance value when subjected to external pressure. Some electrolytes such as AlCl3, FeCl3, etc., due to their unique ionic effect, can further enhance the biocompatibility of the material. Polyvinyl alcohol and the selected electrolyte have good biocompatibility, which makes the hydrogel material have a wide range of application prospects in the fields of medical electronic equipment, wearable devices and other fields that are in direct contact with the human body. At the same time, good skin affinity also ensures the comfort and safety of the material during use. By adjusting the type and proportion of the electrolyte, the shape change rate of the hydrogel material under pressure can be further regulated to meet the needs of pressure-sensitive materials in different fields. For example, in the field of flexible electronic skin, PEDOT:PSS with excellent conductive properties can be selected as the electrolyte to achieve higher sensitivity and a more natural touch.

[0031] The present application further provides a pressure sensor, including: a first electrode layer, a first pressure-sensitive material layer, a second pressure-sensitive material layer, and a second electrode layer, wherein the first pressure-sensitive material layer and the second pressure-sensitive material layer are the aforementioned pressure-sensitive material layers, wherein the surface bump structures 200 of the first pressure-sensitive material layer and the second pressure-sensitive material layer correspond in position, the substrate layer 100 in the first pressure-sensitive material layer is in contact with the first electrode layer, and the substrate layer 100 in the second pressure-sensitive material layer is in contact with the second electrode layer. The first electrode layer and the second electrode layer referred to above are electrodes in a broad sense, which are conductive materials respectively connecting the first pressure-sensitive material layer and the second pressure-sensitive material layer, and their materials, specific structures, etc. are not specifically limited. In some applications, the first electrode layer and the second electrode layer can be used as the plate structure of the capacitor structure, and in other applications, they are only used as structures electrically connecting the first pressure-sensitive material layer and the second pressure-sensitive material layer.

[0032] The first pressure-sensitive material layer and the second pressure-sensitive material layer both use the aforementioned pressure-sensitive material layer, that is, a hydrogel material comprising a truncated cone-shaped bump structure 200 and a high molecular polymer combined with an electrolyte. The positions of the bump structures 200 on the surfaces of the two pressure-sensitive material layers are precisely designed to correspond to each other to ensure that effective deformation control stability can be formed when under pressure, that is, the material deformation remains the same under the same pressure. In addition, the substrate layer 100 in the first pressure-sensitive material layer is closely connected to the first electrode layer, while the substrate layer 100 in the second pressure-sensitive material layer is closely connected to the second electrode layer, thereby improving the overall performance and reliability of the sensor. The bump structures 200 in the first pressure-sensitive material layer and the second pressure-sensitive material layer correspond in position. When external pressure acts on the sensor, the bump structures 200 in the two pressure-sensitive material layers can be in close contact to control the deformation, so that the sensor can more accurately sense the change in pressure and produce a significant change in capacitance value, thereby improving the sensing accuracy, sensitivity and stability.

[0033] In addition, by combining the pressure-sensitive material layer with the electrode layer, the pressure sensor of the present application is more structurally robust and can withstand greater deformation. At the same time, the combination of high molecular polymer and electrolyte makes the hydrogel material have good mechanical properties and chemical stability, further enhancing the stability and durability of the sensor. Due to the presence of the bump structure 200, the sensor can respond quickly and produce a change in capacitance value when subjected to pressure. This fast response speed enables the sensor to capture and respond to dynamic pressure changes in real time, thereby achieving higher dynamic performance. The pressure sensor of the present application has excellent sensing performance, stability and durability, and is suitable for various scenarios that require precise measurement and monitoring of pressure changes, especially in the fields of medical electronic equipment, wearable devices, human-computer interaction, etc. The sensor can provide users with a more accurate and comfortable sensing experience.

[0034] Specifically, the top surfaces of the bump structures 200 are in contact with each other. The design of the top surfaces of the bump structures 200 being in contact with each other enables the sensor to form a stable capacitance structure in the initial state. When the external pressure changes, this foundation can ensure that the change in capacitance value is more stable and reliable, thereby improving the sensing stability of the sensor. Due to the mutual contact of the top surfaces of the bump structures 200, when the external pressure acts on the sensor, the contact area between the bump structures 200 will increase rapidly, resulting in a significant change in capacitance value. This change is closely related to the size and distribution of the pressure, thereby achieving accurate measurement of the pressure and enhancing the sensing sensitivity of the sensor. The design of the top surfaces of the bump structures 200 being in contact with each other also enables the sensor to respond quickly and produce capacitance value changes when subjected to dynamic pressure changes. This fast response speed enables the sensor to capture and respond to dynamic pressure changes in real time, thereby optimizing the dynamic response performance of the sensor. Due to the design of the top surfaces of the bump structures 200 being in contact with each other, the sensor can ensure close contact between the bump structures 200 without additional adjustment or calibration during assembly, which can simplify the assembly process of the sensor and improve production efficiency.

[0035] Specifically, an insulating film layer 300 is also included between the first pressure-sensitive material layer and the second pressure-sensitive material layer. This design not only ensures that a stable capacitive coupling can be formed between the bump structures 200 when the sensor is under pressure, but also effectively prevents direct electrical contact between the first electrode layer and the second electrode layer through the isolation effect of the insulating film layer 300, thereby avoiding the occurrence of short circuit. The presence of the insulating film layer 300 also enables the sensor to maintain good insulation performance and stability during long-term use. The introduction of the insulating film layer 300 effectively avoids the short circuit caused by direct contact between the first electrode layer and the second electrode layer when under pressure, ensures that the sensor can work stably and reliably when under pressure, and improves the reliability and safety of the sensor. The presence of the insulating film layer 300 enables the sensor to maintain good insulation performance during long-term use, helps to reduce the sensing error caused by poor electrical contact between the electrode layers or reduced insulation performance, thereby improving the sensing stability of the sensor. The presence of the insulating film layer 300 also helps to reduce the interference of the external environment on the capacitive coupling, thereby optimizing the capacitive coupling effect. The insulating film layer 300 not only has excellent insulation properties, but also has good mechanical properties and chemical stability. This enables the sensor to resist erosion and damage from the external environment during long-term use, thereby enhancing the durability of the sensor. The specific material of the insulating film layer can be selected from PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene) and other materials. The selected material has the required insulation properties, and can not produce chemical changes with the hydrogel after contact, and has the required chemical stability.

[0036] Specifically, the first electrode layer further includes a first protective layer on the other side relative to the first pressure-sensitive material layer, and the second electrode layer further includes a second protective layer on the other side relative to the second pressure-sensitive material layer, and the first protective layer and the second protective layer are formed of the same hydrogel material as the pressure-sensitive material layer. This design not only enhances the structural strength of the sensor, but also gives the sensor more excellent biocompatibility and air permeability, so that it can better adapt to the complex environment in the body. The introduction of the first protective layer and the second protective layer enhances the structural strength of the sensor, and the two protective layers can resist the impact and damage of the external environment on the sensor, thereby improving the durability and reliability of the sensor. Since the first protective layer and the second protective layer are both made of the same hydrogel material as the pressure-sensitive material layer, the sensor as a whole has excellent biocompatibility, which enables the sensor to better integrate with the biological tissue, reduce rejection and inflammatory reactions, and thus broaden the application range of the sensor in the biomedical field. Although the first protective layer and the second protective layer increase the overall thickness of the sensor, since they are made of the same material as the pressure-sensitive material layer, they do not have a significant effect on the sensing performance of the sensor. On the contrary, the presence of these two protective layers also helps to reduce the interference of the external environment on the internal structure of the sensor, thereby improving the stability and accuracy of the sensing performance. Since the first protective layer and the second protective layer are made of the same material as the pressure-sensitive material layer, they can be produced using the same manufacturing process, thereby simplifying the manufacturing process of the sensor and reducing production costs.

[0037] The present application further provides a method for manufacturing a pressure-sensitive material layer, comprising: preparing raw materials, the raw materials including high molecular polymer, conductive metal salt and solvent; Mixing the high molecular polymer with the solvent and fully dissolving them to obtain a first solution; Adding a conductive metal salt to the first solution, removing bubbles after mixing evenly, and pouring the obtained mixed solution into a mold having a truncated cone-shaped groove to obtain a hydrogel precursor; The hydrogel precursor is subjected to 1 to 5 cycles of freezing and thawing treatment to obtain a pressure-sensitive material layer.

[0038] By selecting raw materials and controlling the preparation process, the prepared pressure-sensitive material layer has excellent mechanical strength, electrical conductivity and biocompatibility, so that the sensor can produce more stable and reliable capacitance changes when under pressure, thereby improving the sensing performance and accuracy of the sensor.

[0039] By repeating the freezing and thawing cycles, the microstructure of the hydrogel can be improved to have a more compact and orderly network structure. This structural optimization helps to improve the mechanical strength and conductivity of the pressure-sensitive material layer, and also helps to improve the sensitivity and response speed of the sensor. This method uses simple raw materials and preparation steps, does not require complex equipment and process conditions, thereby reducing production costs and preparation difficulties, has high production efficiency and repeatability, and is suitable for large-scale production.

[0040] Specifically, the freezing and thawing process cycle includes first cooling to a temperature within a range of -10°C to -30°C and freezing for 4 to 8 hours, and then placing at 15°C to 45°C for 0.5 to 2 hours.

[0041] In addition, the present application further provides an electronic skin, comprising the aforementioned pressure-sensitive material layer or the aforementioned pressure sensor.

[0042] The following is a detailed description of the pressure-sensitive material layer, its manufacturing method, pressure sensor and electronic skin of the present application in a specific embodiment. The specific preparation method is as follows: Prepare 10 parts of PVA (polyvinyl alcohol), 12-20 parts of glycerol, 65-75 parts of water, 0.82.1-11.50 parts of conductive metal salt (electrolyte, one of AlCl3 / FeCl3 / MgCl2 / ZnCl2 / NaCl / PEDOT:PSS) / 0.15 parts of PEDOT:PSS, heat to 85 degrees for 30 minutes to dissolve, pour into a mold (with a truncated cone groove), cool to -20 degrees and freeze for 6 hours, take out and place at room temperature for 1 hour. Step 1, mixing the PVA, glycerol and water, and heating at 80-90° C. for 10-60 minutes to fully dissolve, to obtain solution 1; Step 2, cooling solution 1 to 20-40°C, adding conductive metal salt / PEDOT:PSS, stirring for 5-20 minutes, ultrasonicating for 10 minutes to remove bubbles, and pouring into a mold to obtain a hydrogel precursor; Step 3: Cool the hydrogel precursor to -10 to -30°C and freeze it for 4 to 8 hours, take it out and place it at room temperature for 0.5 to 2 hours, and repeat 1 to 5 cycles to obtain the hydrogel material.

[0043] One or more conductive ions (MgCl2, ZnCl2, NaCl) give PVA hydrogel conductivity and sensing properties. When subjected to tension / pressure, the shape of the hydrogel changes, and the resistance changes accordingly, thereby responding to the tension / pressure, and obtaining good strain sensitivity and pressure sensitivity. When the temperature changes, the migration rate of ions in the hydrogel changes, and the resistance changes, thereby responding to the temperature accordingly, and obtaining good temperature sensitivity. Through this simple method, a pressure-sensitive PVA hydrogel was prepared. The sensor has excellent force test performance, stable performance, excellent pressure-sensitive performance, high sensitivity, good repeatability, simple sensor production method, simple material source and low price.

[0044] The present application relates to a hydrogel sensor structure with a spherical surface, which is used to improve the pressure-sensitive performance of a capacitive pressure sensor. The pressure-sensitive material layer includes the following key features: The hydrogel sensor structure proposed in this application adopts a spherical surface design. The spherical surface can reduce the initial contact area, thereby reducing the tightness of the insulating material and preventing the structure of the adjacent area from being affected when under pressure, thereby reducing the detection error of the corresponding area. When the sensor is subjected to external pressure, the contact area between the spheres will increase accordingly, so that the sensor can achieve a large change in capacitance value when under pressure, thereby improving the pressure-sensitive performance. This application tested hydrogel materials such as PVA / PEDOT:PSS and PVA / FeCl3, and found that these materials have achieved significant performance improvements under the surface spherical structure. The design scheme of this application is applicable to a variety of hydrogel materials and has good versatility.

[0045] As can be seen from the foregoing, the present application provides an innovative pressure-sensitive material layer and a method for manufacturing the same, as well as a pressure sensor and electronic skin based on the pressure-sensitive material layer. The pressure-sensitive material layer achieves the adjustability of the contact area by distributing a plurality of truncated cone-shaped bump structures in an array on the substrate layer, significantly improving the range of capacitance value variation, thereby improving the pressure-sensitive performance. The material layer uses a hydrogel material combining a high molecular polymer and an electrolyte, which has good biocompatibility, skin affinity and versatility, and is suitable for the preparation and application of a variety of hydrogel materials.

[0046] The bump structure is designed to be in a truncated cone shape, which can better adapt to and disperse pressure, achieving a more uniform and stable pressure sensing effect. At the same time, the mutual abutment design of the top surface of the bump structure enables the sensor to form a stable capacitive structure in the initial state, thereby improving the sensing stability and sensitivity. In addition, an insulating film layer is also included between the pressure-sensitive material layers, which effectively prevents direct electrical contact between the electrode layers, avoids the occurrence of short circuits, and maintains good insulation performance and stability. The other side of the first electrode layer and the second electrode layer also includes a first protective layer and a second protective layer formed of the same hydrogel material, which enhances the structural strength of the sensor and broadens its application range in the biomedical field.

[0047] The present application also provides a method for manufacturing a pressure-sensitive material layer. By selecting raw materials and a preparation process, the pressure-sensitive material layer prepared has excellent mechanical strength, electrical conductivity and biocompatibility. The method uses simple raw materials and preparation steps, has high production efficiency and repeatability, and is suitable for large-scale production.

[0048] The pressure sensor and electronic skin based on the pressure-sensitive material layer have excellent sensing performance, stability and durability, and are suitable for various scenarios that require accurate measurement and monitoring of pressure changes, especially in the fields of medical electronic equipment, wearable devices, human-computer interaction, etc., and can provide users with a more accurate and comfortable sensing experience. In addition, this application also tested a variety of hydrogel materials, such as PVA / PEDOT:PSS and PVA / FeCl3, and found that these materials have achieved significant performance improvements under the surface spherical structure, further verifying the versatility and practicality of the design scheme of this application.

[0049] The above is only a specific implementation of the present application, and any other improvements made based on the concept of the present application are deemed to be within the protection scope of the present application.

Claims

1. A pressure-sensitive material layer, characterized in that: It includes a substrate layer and a bump structure on the substrate layer; The number of the bump structures is multiple, and the array is distributed on the substrate layer; The substrate layer and the bump structure are formed of a hydrogel material.

2. The pressure-sensitive material layer according to claim 1, characterized in that: The convex block structure is a truncated cone.

3. The pressure-sensitive material layer according to claim 1, characterized in that: The hydrogel material comprises a high molecular polymer and an electrolyte.

4. The pressure-sensitive material layer according to claim 3, characterized in that: The high molecular polymer is selected as polyvinyl alcohol, and the electrolyte is selected from one or more of AlCl3, FeCl3, MgCl2, ZnCl2, NaCl, and PEDOT: PSS.

5. A pressure sensor, characterized in that: include: A first electrode layer, a first pressure-sensitive material layer, a second pressure-sensitive material layer, and a second electrode layer; The first pressure-sensitive material layer and the second pressure-sensitive material layer are the pressure-sensitive material layers according to any one of claims 1 to 4; The surface bump structures of the first pressure-sensitive material layer and the second pressure-sensitive material layer correspond to each other, the substrate layer in the first pressure-sensitive material layer is connected to the first electrode layer, and the substrate layer in the second pressure-sensitive material layer is connected to the second electrode layer.

6. The pressure sensor according to claim 5, characterized in that: The top surfaces of the bump structures abut against each other.

7. The pressure sensor according to claim 5, characterized in that: An insulating film layer is also included between the first pressure-sensitive material layer and the second pressure-sensitive material layer.

8. A method for manufacturing a pressure-sensitive material layer, characterized in that: include: preparing raw materials, the raw materials including high molecular polymer, conductive metal salt and solvent; Mixing the high molecular polymer with the solvent and fully dissolving them to obtain a first solution; Adding a conductive metal salt to the first solution, removing bubbles after mixing evenly, and pouring the obtained mixed solution into a mold having a truncated cone-shaped groove to obtain a hydrogel precursor; The hydrogel precursor is subjected to 1 to 5 cycles of freezing and thawing treatment to obtain a pressure-sensitive material layer.

9. The method for manufacturing a pressure-sensitive material layer according to claim 8, characterized in that: The freezing and thawing process cycle includes first cooling to a temperature within a range of -10°C to -30°C and freezing for 4 to 8 hours, and then placing at 15°C to 45°C for 0.5 to 2 hours.

10. An electronic skin, characterized in that: It comprises the pressure-sensitive material layer as described in claims 1-4 or the pressure sensor as described in claims 5-7.

Images