Flexible pressure capacitance sensor and preparation method and regeneration method thereof

Abstract

The invention discloses a flexible pressure capacitance sensor and a preparation method and a regeneration method thereof, relates to the technical field of flexible sensors, and discloses a preparation method of the flexible pressure capacitance sensor, which comprises the following steps: adding a conductive filler into a thermoplastic elastomer, and uniformly stirring to obtain polymer slurry; pouring the polymer slurry into a mold, curing, and demolding to obtain a functional layer in which the conductive filler is distributed in a gradient manner in the vertical direction; and combining the at least two functional layers to obtain the flexible pressure capacitance sensor. According to the invention, the recycling and regeneration process of the flexible pressure capacitance sensor is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible sensor, in particular to a flexible pressure capacitive sensor and a preparation method and a regeneration method thereof. BACKGROUND

[0002] As an important type of sensor, flexible pressure capacitive sensor has shown great application potential in many frontier fields such as wearable devices, intelligent medical monitoring, human-computer interaction interface and bionic robots. Its working principle is based on the change of capacitance to perceive external pressure. When external pressure is applied, the capacitance structure inside the sensor will change accordingly, which will cause the change of capacitance value. By detecting the amount of capacitance change, the pressure can be accurately measured. Compared with traditional rigid sensors, flexible pressure capacitive sensors have good flexibility, bendability and stretchability, and can better fit irregular surfaces and adapt to complex application scenarios.

[0003] Conventional flexible pressure capacitive sensors mainly use a large number of composite material systems as a substrate builder. During the construction process, various materials usually form a three-dimensional cross-linked network after curing, becoming a thermoset material that is not easy to dissolve in solvent or melt, and is not easy to recycle and reuse.

[0004] The above content is only used to assist in understanding the technical solutions of the present application and does not mean that the above content is prior art. SUMMARY

[0005] The main purpose of the present application is to provide a flexible pressure capacitive sensor and a preparation method and a regeneration method thereof, aiming to solve the technical problem that flexible pressure capacitive sensors are not easy to recycle and reuse.

[0006] To achieve the above purpose, the present application provides a preparation method of a flexible pressure capacitive sensor, which comprises the following steps: Adding conductive fillers to a thermoplastic elastomer, stirring uniformly to obtain a polymer slurry; Pouring the polymer slurry into a mold and curing to obtain a functional layer with gradient distribution of conductive fillers in the vertical direction after demolding; Combining at least two functional layers to obtain a flexible pressure capacitive sensor.

[0007] In a feasible embodiment, the functional layer comprises an electrode layer and a dielectric layer, wherein the content of conductive fillers in the electrode layer is greater than that in the dielectric layer, and the step of combining at least two functional layers to obtain a flexible pressure capacitive sensor comprises: Coating a bonding solvent on the electrode layer and the dielectric layer of each functional layer; The two functional layers are attached, wherein the dielectric layer is located between the two electrode layers after attachment; The bonding solvent is volatilized, and solidified to obtain the flexible pressure capacitive sensor.

[0008] In an embodiment, the bonding solvent includes toluene and / or xylene.

[0009] In an embodiment, the thermoplastic elastomer includes at least one of SEBS, SIS or EVA. In an embodiment, the conductive filler includes at least one of carbon nanotubes, silver nanowires or conductive carbon powder.

[0010] In an embodiment, the conductive filler: the thermoplastic elastomer = 1:10~3:10 by mass ratio. In an embodiment, the solid content in the polymer slurry is 20~40% by mass fraction.

[0011] In an embodiment, the mold surface has a microstructure.

[0012] The embodiments of the present application also provide a flexible pressure capacitive sensor prepared by the method described above.

[0013] The embodiments of the present application also provide a regeneration method of a flexible pressure capacitive sensor, which is applied to the flexible pressure capacitive sensor prepared by the method described above or the flexible pressure capacitive sensor described above, and the regeneration method includes the following steps: The flexible pressure capacitive sensor is dissolved in a dissolving solvent to obtain a polymer slurry; The polymer slurry is poured into a mold and solidified, and the functional layer with gradient distribution of the conductive filler in the vertical direction is obtained after demolding; At least two functional layers are combined to obtain a new flexible pressure capacitive sensor.

[0014] In an embodiment, the dissolving solvent includes toluene and / or xylene.

[0015] One or more technical solutions proposed in this application have at least the following technical effects: A method for preparing a flexible pressure-capacitive sensor is provided, which involves adding conductive fillers to a thermoplastic elastomer and stirring to obtain a polymer slurry; then, pouring the polymer slurry into a mold and curing it, and after demolding, obtaining a functional layer with a gradient distribution of conductive fillers in the vertical direction; finally, combining at least two of the functional layers to obtain a flexible pressure-capacitive sensor. This application utilizes the property that thermoplastic elastomers can soften and flow under certain temperature conditions, and can return to a solid state after cooling. Adding conductive fillers to the elastomer allows them to be uniformly dispersed in the elastomer through physical action, forming a polymer slurry without affecting the thermoplasticity of the elastomer. Curing the polymer slurry in a mold yields a functional layer with a relatively simple and uniform structure. The functional layer is formed through a physical curing process without complex chemical bonding changes. The conductive fillers in the functional layer exhibit a gradient distribution under gravity, serving as the functional layer for constructing a capacitive sensor. Furthermore, combining at least two functional layers physically yields a flexible pressure-capacitive sensor. This application also enables the recycling and regeneration of the flexible pressure-capacitive sensor. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the fabrication method of the flexible pressure capacitive sensor involved in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the flexible pressure-capacitive sensor involved in the embodiments of this application. Figure One ; Figure 3 This is a schematic diagram of the structure of the flexible pressure-capacitive sensor involved in the embodiments of this application. Figure Two .

[0017] Explanation of icon numbers 10. Functional layer; 101. Dielectric layer; 102. Electrode layer; 103. Microstructure; 20. Conductive filler.

[0018] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0020] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of a flexible pressure capacitive sensor and its fabrication and regeneration methods. However, unnecessary details may be omitted. For example, detailed descriptions of well-known facts and repetitive descriptions of identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0023] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0024] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0025] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0026] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0027] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the technical solution of this application is further described below in conjunction with the accompanying drawings and embodiments. However, this application is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims made in this application.

[0028] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0030] Flexible capacitive pressure sensors, as an important type of sensor, have demonstrated enormous application potential in many cutting-edge fields such as wearable devices, intelligent medical monitoring, human-computer interfaces, and bionic robots. Their working principle is based on sensing external pressure through changes in capacitance. When external pressure is applied, the capacitor structure inside the sensor changes accordingly, resulting in a change in capacitance. By detecting this change in capacitance, accurate pressure measurement can be achieved. Compared to traditional rigid sensors, flexible capacitive pressure sensors have excellent flexibility, bendability, and stretchability, enabling them to better conform to irregular surfaces and adapt to complex application scenarios.

[0031] In conventional technologies, the substrate material of flexible pressure-capacitive sensors is usually a thermosetting material. After solidification during the manufacturing process, it becomes an infusible and insoluble substance, making it difficult to restore it to a usable state. Furthermore, flexible pressure-capacitive sensors typically require 3D printing or even photolithography equipment for fabrication, which involves complex steps and high costs.

[0032] This application provides a method for fabricating a flexible pressure-capacitive sensor. A polymer slurry is prepared by adding conductive filler to a thermoplastic elastomer and stirring until homogeneous. The polymer slurry is then poured into a mold and cured. After demolding, a functional layer with a gradient distribution of conductive filler in the vertical direction is obtained. Finally, at least two of the functional layers are combined to obtain the flexible pressure-capacitive sensor. This application utilizes the property that thermoplastic elastomers can soften and flow under certain temperature conditions, and then return to a solid state after cooling. The addition of conductive filler allows it to be uniformly dispersed in the thermoplastic elastomer through physical action, forming a polymer slurry without affecting the thermoplasticity of the elastomer. Curing the polymer slurry in a mold yields a functional layer with a relatively simple and uniform structure. The functional layer is formed through a physical curing process without complex chemical bonding changes. The conductive filler in the functional layer exhibits a gradient distribution under gravity, serving as the functional layer for constructing a capacitive sensor. Furthermore, at least two functional layers are physically combined to obtain the flexible pressure-capacitive sensor. This application achieves the recyclability and regeneration of the flexible pressure-capacitive sensor. Furthermore, the gradient distribution of conductive fillers is achieved through gravity, a process that is simple and low-cost.

[0033] Reference Figure 1 The first aspect of this application provides a method for fabricating a flexible pressure capacitive sensor, comprising the following steps: Step S10: Add conductive filler to thermoplastic elastomer and stir evenly to obtain polymer slurry; In one feasible embodiment, a thermoplastic elastomer is provided as the matrix material, giving the sensor the necessary mechanical properties and flexibility to conform to human skin and adapt to dynamic changes during pulse measurement. The thermoplastic elastomer is dissolved in a solvent, such as toluene or xylene, and a conductive filler is added. The purpose of adding the conductive filler is to impart electrical conductivity to the material. When an external force is applied to the material, the distance and contact state between the conductive fillers change, resulting in a change in the material's resistance. This change in resistance can be detected and recorded, and then used to sense minute pressure changes caused by the pulse. After adding the conductive filler to the thermoplastic elastomer, it needs to be thoroughly stirred to ensure that the conductive filler is uniformly dispersed within the thermoplastic elastomer. Uniform dispersion ensures consistent conductivity throughout the material, improving the stability and reliability of the sensor.

[0034] Optionally, thermoplastic elastomers are polymeric materials that combine the properties of rubber and thermoplastic plastics. They have good elasticity, flexibility and processability. They can exhibit the elasticity of rubber at room temperature, while melting and flowing like plastic when heated, making them easy to mold and process.

[0035] In one feasible embodiment, the thermoplastic elastomer includes at least one of SEBS, SIS, or EVA; And / or, the conductive filler includes at least one of carbon nanotubes, silver nanowires, or conductive carbon powder.

[0036] Optionally, SEBS (Styrene-Ethylene-Butylene-Styrene Block Copolymer) is obtained by hydrogen saturation of a styrene-butadiene-styrene block copolymer. Its molecular chain contains hard segments (polystyrene segments) and soft segments (polybutene segments), giving SEBS excellent aging resistance, weather resistance, and chemical corrosion resistance, maintaining stable performance under various environmental conditions. Simultaneously, it also exhibits good flexibility and low-temperature performance, maintaining good elasticity even at relatively low temperatures.

[0037] Optionally, SIS (Styrene-Isoprene-Styrene Block Copolymer) is a thermoplastic block copolymer formed by the polymerization of styrene and isoprene. Its molecular chain contains hard segments (polystyrene) and soft segments (polyisoprene). SIS exhibits high elasticity and viscosity; its viscosity allows it to better encapsulate and disperse conductive fillers when mixed with them, contributing to improved uniformity of the conductive filler dispersion in the polymer matrix and thus enhancing the material's conductivity. Furthermore, SIS also possesses good low-temperature elasticity and flexibility, enabling it to adapt to dynamic changes during pulse measurement.

[0038] Optionally, EVA (ethylene-vinyl acetate copolymer) is a polymer material copolymerized from ethylene and vinyl acetate. EVA possesses good flexibility, impact resistance, and biocompatibility. Its flexibility allows it to conform well to human skin, improving the wearing comfort of flexible pressure capacitive sensors; its biocompatibility ensures that the sensor will not cause adverse reactions such as allergies when in contact with the human body. In addition, EVA also has good chemical resistance and weather resistance, which can protect the internal conductive structure to a certain extent.

[0039] Optionally, carbon nanotubes are tubular nanomaterials composed of carbon atoms, typically with diameters in the nanometer range and lengths reaching the micrometer or even millimeter range, exhibiting a high aspect ratio. Carbon nanotubes possess strong electrical conductivity and high carrier mobility. Simultaneously, they also possess good mechanical properties and chemical stability, enabling them to form stable conductive networks within polymer matrices. Due to their nanoscale effect, carbon nanotubes can achieve conductive properties in materials with relatively low filler content, which is beneficial for maintaining the original properties of thermoplastic elastomers.

[0040] Alternatively, silver nanowires are metallic materials with one-dimensional nanostructures, typically ranging in diameter from tens to hundreds of nanometers, and lengths reaching tens of micrometers or even longer. Silver nanowires possess extremely high conductivity, enabling the formation of continuous conductive networks with relatively low filler content, thereby significantly improving the material's conductivity. Furthermore, silver nanowires exhibit good flexibility and bendability, allowing them to adapt to bending and deformation during the use of flexible pressure-capacitance sensors.

[0041] Optionally, conductive carbon powder is typically a powdered substance obtained from carbon materials such as carbon black through special processing, possessing a large specific surface area and abundant pore structure. Conductive carbon powder exhibits good electrical conductivity and chemical stability, is relatively inexpensive, and is widely available. Adding conductive carbon powder to thermoplastic elastomers can effectively reduce the material's resistance and improve its conductivity. Simultaneously, the particle morphology of conductive carbon powder can form a certain physical cross-linking structure within the polymer matrix, contributing to improved mechanical properties of the material.

[0042] In one feasible implementation, the conductive filler to thermoplastic elastomer ratio is 1:10 to 3:10 by mass. And / or, the mass fraction of solids in the polymer slurry is 20-40%.

[0043] Optionally, the mass ratio of conductive filler to thermoplastic elastomer can be 1:10, 1.2:10, 1.4:10, 1.6:10, 1.8:10, 2:10, 2.2:10, 2.4:10, 2.6:10, 2.8:10, 3:10, etc. When the mass ratio of conductive filler to thermoplastic elastomer is less than 1:10, the content of conductive filler is relatively low. At this time, it is difficult for the conductive filler to form a complete and continuous conductive network in the polymer matrix, and the conductivity is relatively weak. When the mass ratio is greater than 3:10, it may lead to a deterioration in the processing performance of the material, such as increased viscosity and reduced fluidity, affecting the preparation process of the functional layer. It may also reduce the flexibility and elasticity of the material, affecting the wearing comfort and service life of the sensor. Conductive filler: The mass ratio of thermoplastic elastomer to conductive filler is in the range of 1:10 to 3:10. This ensures that the material has good conductivity while taking into account the original properties and processing properties of the thermoplastic elastomer. This results in a good balance between conductivity, flexibility and formability in the prepared functional layer, thereby meeting the performance requirements of flexible pressure capacitive sensors.

[0044] Optionally, the mass fraction of solids in the polymer slurry can be 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, etc. The solids in the polymer slurry are a mixture of thermoplastic elastomer and conductive filler. If the mass fraction of solids in the polymer slurry is too low, it may require the removal of a large amount of solvent during drying or curing, increasing processing time and cost, and potentially causing shrinkage and deformation. If the solid content in the polymer slurry is too high, the viscosity increases. Excessive viscosity makes stirring and molding difficult, potentially leading to uneven dispersion of the conductive filler. Increased buoyancy of the polymer slurry makes it difficult for the conductive filler to settle under gravity and achieve a gradient distribution. Furthermore, excessive viscosity affects the curing process when poured into the mold, making it difficult to level and cover the microstructure on the mold surface, thus affecting the overall conductivity of the sensor. A solids mass fraction in the polymer slurry within the range of 20% to 40% provides a suitable viscosity, facilitating processing while ensuring good dispersion of the conductive filler and the performance of the functional layer. Meanwhile, the solid mass fraction within this range allows for the drying or curing process to be completed within a reasonable time and cost, resulting in a functional layer with stable performance and reliable quality, meeting the requirements for the fabrication of flexible pressure capacitive sensors.

[0045] Step S20: Pour the polymer slurry into a mold and let it solidify. After demolding, a functional layer with a conductive filler gradient distribution in the vertical direction is obtained. In one feasible embodiment, the prepared polymer slurry is poured into a pre-designed mold. The shape and size of the mold determine the final shape and size of the functional layer. Molds of different shapes and sizes can be manufactured according to the design requirements of the flexible pressure-capacitance sensor to meet the needs of practical applications. During the curing process, the thermoplastic elastomer undergoes physicochemical changes such as cross-linking or crystallization, forming a stable three-dimensional network structure, thereby fixing the position of the conductive filler. During curing, gravity causes the conductive filler to form a gradient distribution in the vertical direction, with a higher content of conductive filler in the upper functional layer of the mold and a lower content in the lower functional layer. This gradient distribution allows the functional layer to have different conductivity and mechanical properties in different directions, thereby improving the sensor's sensitivity and selectivity to pulse signals. After curing, the formed functional layer is removed from the mold.

[0046] Optionally, after the polymer slurry is poured onto the mold surface, it is moved to a ventilated place to evaporate the solvent and solidify. The solidified gradient polymer film is then peeled out of the mold to obtain the functional layer of the sensor.

[0047] In one feasible implementation, the mold surface has a microstructure.

[0048] In one feasible embodiment, the microstructure on the mold surface provides greater deformation space for the functional layer, thus allowing the sensor to undergo greater displacement under pressure and achieve greater capacitance change.

[0049] Optionally, selecting a mold based on the shape of the target microstructure can provide random, irregular, rough structures (such as uneven peaks and valleys). Further, regular, ordered microstructures (such as pyramids, cylinders, or pyramidal arrays) can be fabricated using photolithography, micromachining, or laser processing. Spraying a thin layer of release agent (such as silicone) onto the mold surface, or performing plasma treatment, greatly facilitates the subsequent "peeling out" of the cured functional layer, preventing damage to the microstructure.

[0050] Optionally, since the microstructure is built at the bottom of the mold, the conductive filler also settles at the bottom of the mold under the influence of gravity, so the microstructure is located on the electrode layer.

[0051] Step S30: Combine at least two functional layers to obtain a flexible pressure capacitive sensor.

[0052] In one feasible embodiment, combining at least two functional layers with a vertically distributed conductive filler gradient can further improve sensor performance. The combination of multiple functional layers forms a complete flexible pressure-capacitance sensor. The synergistic effect between different functional layers can enhance the sensor's ability to sense and convert pulse signals. For example, the combined conductivity and mechanical properties of different functional layers can more accurately capture minute pressure changes caused by the pulse and convert them into electrical signals, thereby enabling pulse measurement and monitoring.

[0053] Optionally, in practical applications, different measurement needs place vastly different demands on the performance of sensors and other devices. By combining multiple functional layers, the performance of the devices can be flexibly adjusted and optimized to better meet diverse practical measurement requirements.

[0054] In one feasible embodiment, the functional layer includes an electrode layer and a dielectric layer, wherein the content of conductive filler in the electrode layer is greater than the content of conductive filler in the dielectric layer. The step of combining at least two functional layers to obtain a flexible pressure-capacitance sensor includes: Step S31: Coat the electrode layer and dielectric layer of each functional layer with a bonding solvent; In one feasible embodiment, the adhesive solvent plays a crucial role in the bonding process of the functional layers, enabling a strong connection between different functional layers.

[0055] Alternatively, the adhesive solvent can be applied manually, by dipping the electrode layer and dielectric layer of the functional layer into the adhesive solvent, or by spraying with a spray gun.

[0056] In one feasible embodiment, the adhesive solvent includes toluene and / or xylene.

[0057] Step S32: The two functional layers are bonded together, wherein the bonded dielectric layer is located between the two electrode layers; In one feasible embodiment, to construct a complete capacitive structure, a dielectric layer is sandwiched between two electrode layers. When external pressure is applied to the sensor, the physical properties of the dielectric layer, such as its thickness and shape, change, thereby causing a change in the capacitance between the two electrode layers. By detecting this change in capacitance, physical quantities such as pressure can be measured.

[0058] Optionally, refer to Figure 2 The electrode layer of one functional layer is bonded to the dielectric layer of another functional layer. Two functional layers 10 are provided, in which conductive filler 20 is distributed in a gradient from top to bottom. Each functional layer includes a dielectric layer 101 and an electrode layer 102. The electrode layer 102 has a higher content of conductive filler 20 than the dielectric layer 101, and the electrode layer 102 has microstructures. The electrode layer 102 of one functional layer 10 is bonded to the dielectric layer 101 of the other functional layer 10 using an adhesive solvent to assemble a flexible pressure-capacitance sensor. The dielectric layer 101 between the two electrode layers 102 enables the sensor's performance.

[0059] Optionally, refer to Figure 3 Two functional layers 10 are provided by bonding the dielectric layers of one functional layer to the dielectric layers of another functional layer. The conductive filler 20 is distributed in a gradient from top to bottom. Each functional layer includes a dielectric layer 101 and an electrode layer 102. The electrode layer 102 contains more conductive filler 20 than the dielectric layer 101 and has microstructures. The dielectric layers 101 of one functional layer 10 and the dielectric layers 101 of the other functional layer 10 are bonded together using an adhesive solvent to assemble a flexible pressure-capacitance sensor. The dielectric layer 101 is located between the two electrode layers 102, enabling the sensor's performance.

[0060] In step S33, the adhesive solvent is evaporated and cured to obtain a flexible pressure capacitive sensor.

[0061] In one feasible embodiment, the electrode layer and dielectric layer of the functional layer are quickly passed through a solvent, pressed together in sequence, and then cured after the solvent has been completely evaporated by heating, thus obtaining a flexible pressure capacitive sensor.

[0062] This application also provides a method for regenerating a flexible pressure-capacitive sensor, applied to a flexible pressure-capacitive sensor prepared by the above method. The regeneration method includes the following steps: Step A10: Dissolve the flexible pressure capacitive sensor in a solvent to obtain a polymer slurry; In one feasible embodiment, the used flexible pressure-capacitive sensor undergoes preliminary processing, transforming it from its original solid structure into a reprocessable liquid or semi-liquid slurry. A suitable solvent dissolves the polymer matrix, dispersing the polymer molecular chains under the action of solvent molecules, thereby uniformly dispersing the conductive filler in the solvent and reforming a polymer slurry with a certain degree of fluidity.

[0063] In one feasible embodiment, the dissolving solvent includes toluene and / or xylene.

[0064] Optionally, the dissolving solvent can be the same as the binding solvent, making the preparation and regeneration of the flexible pressure capacitive sensor prepared in this embodiment simple and easy to operate.

[0065] Step A20: Pour the polymer slurry into the mold and let it solidify. After demolding, a functional layer with a gradient distribution of conductive filler in the vertical direction is obtained. In one feasible embodiment, the polymer slurry is reformulated into a functional layer with a specific structure, and the conductive filler is arranged in a gradient distribution in the vertical direction, and the functional layer is re-prepared under gravity.

[0066] Step A30: Combine at least two functional layers to obtain a new flexible pressure capacitive sensor.

[0067] In one feasible embodiment, the functional layers are combined to create a new flexible pressure-capacitive sensor, enabling the recyclable and regenerable process of the flexible pressure-capacitive sensor.

[0068] Optionally, the flexible pressure-capacitive sensor prepared above can be used as a capacitive fingertip pulse sensor. Pulse waves carry rich information about the human circulatory system, making pulse wave monitoring particularly important for early screening of cardiovascular and cerebrovascular diseases. Fingertip pulse sensors are highly portable and possess excellent sensing performance, showing great potential for widespread application in early community screening of cardiovascular and cerebrovascular event chains. The materials used in the capacitive fingertip pulse sensor prepared above can be recycled and reused, and the preparation process is simple and low-cost.

[0069] This embodiment uses toluene and / or xylene as a solvent to dissolve the materials in the sensor, thereby re-preparing a polymer slurry. This slurry is then repeatedly cured using a mold to obtain the functional layer of the conductive filler gradient. Finally, a new flexible pressure-capacitive sensor is fabricated using this functional layer. This achieves the recycling and reuse of the sensor materials, and the recycling steps are simple, reducing recycling costs and improving recycling efficiency.

[0070] This embodiment involves adding conductive fillers to a thermoplastic elastomer and stirring to obtain a polymer slurry. The polymer slurry is then poured into a mold and cured. After demolding, a functional layer with a vertically gradient distribution of conductive fillers is obtained. Finally, at least two functional layers are combined to obtain a flexible pressure-capacitive sensor. This embodiment utilizes the property that thermoplastic elastomers can soften and flow under certain temperature conditions, and then return to a solid state after cooling. Conductive fillers are added to the elastomer, and the conductive fillers are uniformly dispersed in the elastomer through physical action to form a polymer slurry, without affecting the thermoplasticity of the elastomer. Curing the polymer slurry in a mold yields a functional layer with a relatively simple and uniform structure. The functional layer is formed through a physical curing process without complex chemical bonding changes. The conductive fillers in the functional layer exhibit a gradient distribution under gravity, serving as the functional layer for constructing a capacitive sensor. Furthermore, at least two functional layers are physically combined to obtain a flexible pressure-capacitive sensor. This embodiment achieves the recyclability of the flexible pressure-capacitive sensor. Furthermore, the gradient distribution of conductive fillers achieved through gravity is simple and low-cost.

[0071] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the patent protection scope of this application.

Claims

1. A method for fabricating a flexible pressure-capacitive sensor, characterized in that, The method includes the following steps: A polymer slurry is prepared by adding conductive filler to a thermoplastic elastomer and stirring until homogeneous. The polymer slurry is poured into a mold and cured. After demolding, a functional layer with the conductive filler gradient distributed in the vertical direction is obtained. By combining at least two of the aforementioned functional layers, a flexible pressure-capacitance sensor is obtained.

2. The method for fabricating a flexible pressure-capacitive sensor as described in claim 1, characterized in that, The functional layer includes an electrode layer and a dielectric layer, wherein the content of conductive filler in the electrode layer is greater than the content of conductive filler in the dielectric layer, and the step of combining at least two of the functional layers to obtain a flexible pressure-capacitance sensor includes: A bonding solvent is coated on the electrode layer and dielectric layer of each of the functional layers; Two functional layers are bonded together, wherein the bonded dielectric layer is located between the two electrode layers; The adhesive solvent is evaporated and then cured to obtain the flexible pressure-capacitance sensor.

3. The method for fabricating a flexible pressure-capacitive sensor as described in claim 2, characterized in that, The adhesive solvent includes toluene and / or xylene.

4. The method for fabricating a flexible pressure-capacitive sensor as described in claim 1, characterized in that, The thermoplastic elastomer includes at least one of SEBS, SIS, or EVA; And / or, the conductive filler includes at least one of carbon nanotubes, silver nanowires, or conductive carbon powder.

5. The method for fabricating a flexible pressure-capacitive sensor as described in claim 1, characterized in that, The ratio of the conductive filler to the thermoplastic elastomer by mass is 1:10 to 3:

10.

6. The method for fabricating a flexible pressure-capacitive sensor as described in claim 1, characterized in that, The mass fraction of solids in the polymer slurry is 20-40%.

7. The method for fabricating a flexible pressure-capacitive sensor as described in claim 1, characterized in that, The surface of the mold has a microstructure.

8. A flexible pressure-capacitive sensor, characterized in that, The flexible pressure-capacitive sensor is prepared by the flexible pressure-capacitive sensor preparation method according to any one of claims 1 to 7.

9. A method for regenerating a flexible pressure capacitive sensor, characterized in that, The regeneration method, applied to a flexible pressure-capacitive sensor fabricated by the method described in any one of claims 1 to 7, or a flexible pressure-capacitive sensor as described in claim 8, comprises the following steps: The flexible pressure capacitive sensor is dissolved in a solvent to obtain a polymer slurry; The polymer slurry is poured into a mold and cured. After demolding, a functional layer with the conductive filler gradient distributed in the vertical direction is obtained. By combining at least two of the aforementioned functional layers, a new flexible pressure-capacitance sensor is obtained.

10. The method for regenerating a flexible pressure capacitive sensor as described in claim 9, characterized in that, The dissolving solvent includes toluene and / or xylene.

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