Flexible multi-layer spun sensor and packaging method of flexible multi-layer spun sensor

Abstract

The present invention relates to a flexible multilayer electrospun sensor and a packaging method of the flexible multilayer electrospun sensor. The flexible multilayer electrospun sensor of the present invention includes an upper electrode layer, a lower electrode layer, and two or more electrospun polymer fiber layers sandwiched between the upper electrode layer and the lower electrode layer, the upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive substance and a polymer, the difference between the minimum value and the maximum value of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the upper electrode layer, and the lower electrode layer is less than 5℃; there are bonding points between adjacent electrospun polymer fiber layers formed by thermal melting; there are bonding points between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer and between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer formed by thermal melting.

Description

Technical Field This invention relates to a flexible multilayer spinning sensor and a packaging method for the flexible multilayer spinning sensor. Background Technology As research continues, wearable electronic devices not only need to meet functional requirements but also face higher demands for flexibility and comfort. Traditional rigid sensors can typically withstand strains of less than 5%, making it difficult for them to withstand significant deformations, which greatly limits their application in wearable electronic devices. Therefore, research on flexible wearable sensors is essential. Wearable sensors are often manufactured using multilayer spinning technology. However, multilayer spun sensors face mechanical delamination issues during use, leading to instability in the detected signals. Therefore, encapsulating multiple layers of spun film together is an urgent choice to improve the quality of sensor data acquisition. Furthermore, maintaining the thinness and breathability while encapsulating the layers is also a key concern. Addressing these issues comprehensively in the encapsulation of multilayer spun film presents a significant challenge. Currently, for the packaging of rigid objects and flexible circuits, the common approach is to add materials to cover the sensor and circuit. However, if traditional packaging methods are used, the characteristics of thinness and breathability of the spun yarn will be lost, and the stability problem of the sensor caused by mechanical mismatch cannot be solved. In addition, for fiber film devices, traditional encapsulation techniques rely on tapes, adhesives, or directly covering the fiber film device with materials. These methods have been shown to impair sensor sensitivity and reduce film permeability and lightweight. With the continuous advancement of flexible technology, especially the rapid development of spun film sensors, there is an urgent need to provide a packaging method that is simple to operate and well compatible with modern scientific research and industrial development. Summary of the Invention <Problem to be solved by the invention> In view of the above, the technical problem to be solved by the present invention is to provide a flexible multilayer spinning sensor that has excellent stability and robustness, while maintaining air permeability and lightweight, and can be obtained in an easy manner. The technical problem to be solved by the present invention is to provide a packaging method for a flexible multilayer spinning sensor, which can easily obtain a flexible multilayer spinning sensor with excellent stability and robustness, while maintaining air permeability and lightweight. <Solutions for solving the problem>

[0001] A flexible multilayer spun sensor includes: an upper electrode layer, a lower electrode layer, and two or more electrospun polymer fiber layers sandwiched between the upper electrode layer and the lower electrode layer. The upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer. The difference between the minimum and maximum values ​​of the melting temperatures of the polymers contained in the two or more electrospun polymer fiber layers, the polymers contained in the upper electrode layer, and the polymers contained in the lower electrode layer is less than 5°C. In the two or more electrospun polymer fiber layers, there are bonding points A between adjacent electrospun polymer fiber layers formed by thermal melting. There is a bonding point B between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, formed by thermal melting. There is a bonding point C between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer, which is formed by thermal melting.

[0002] According to the flexible multilayer spinning sensor described in [1], each of the electrospun polymer fiber layers is formed by electrospinning a thermoplastic stretchable and resilient resin composition.

[0003] The flexible multilayer spinning sensor according to [2] is particularly characterized in that the thermoplastic stretchable and resilient resin composition comprises polyurethane.

[0004] The flexible multilayer spun sensor according to any one of [1] to [3], wherein the thickness of the single-layer electrospun polymer fiber layer is 2 to 100 μm; and / or The average diameter of the fibers constituting the electrospun polymer fiber layer is 1 to 5 μm.

[0005] According to any one of [1] to [4], the tensile strength between the two electrospun polymer fiber layers having the bonding point A can be more than 70% of the tensile strength of a single electrospun polymer fiber layer; and / or At the junction A, the adjacent electrospun polymer fiber layers are mainly connected to each other by fibers.

[0006] The flexible multilayer spinning sensor according to any one of [1] to [5], wherein the upper electrode layer and the lower electrode layer are each independently a composite layer comprising metal fibers and electrospun polymer fibers.

[0007] According to any one of [1] to [6], the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer and the melting temperature of the polymer contained in the lower electrode layer are substantially the same.

[0008] A packaging method for a flexible multilayer spun sensor, comprising: (1) Prepare two or more electrospun polymer fiber layers, an upper electrode layer, and a lower electrode layer. The upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer. The difference between the minimum and maximum values ​​of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is less than 5°C. (2) The upper electrode layer, the two or more electrospun polymer fiber layers, and the lower electrode layer are stacked together in sequence to obtain a laminate. (3) The encapsulation device is placed on the surface of the laminate and hot-pressed, thereby forming bonding points in the laminate between adjacent electrospun polymer fiber layers, between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, and between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer by thermal melting. When the average value of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is set to T℃, the hot pressing temperature is a temperature of (T-12)~(T+25)℃.

[0009] According to the encapsulation method described in [8], the hot pressing time is 0.5 to 20 minutes.

[0010] According to the packaging method described in [8] or [9], the packaging equipment may be a packaging mold or a hot soldering gun. <The Effects of the Invention> In this invention, the desired technical effect is achieved through the above technical solution. Specifically, in the encapsulation method of the present invention, no additive materials other than the electrospun polymer fiber layer are required during the encapsulation process. By utilizing the melting properties of the polymer, bonding points exist between adjacent layers of the multilayer electrospun polymer layer, between the upper electrode layer and the electrospun polymer fiber layer, and between the lower electrode layer and the electrospun polymer fiber layer (in particular, these bonding points can have high tensile strength and / or substantially do not damage the fiber structure of the adjacent layers), reducing the probability of delamination between layers, improving the stability of the sensing signal, and maintaining the air permeability and lightweight of the polymer fiber layer. Attached Figure Description Figure 1 The diagram schematically illustrates the process of forming a bonding point between two electrospun polymer fiber layers (films) by thermal melting using an encapsulation mold. Figure 2 and Figure 3 The image shows the melting changes of the electrospun polymer fiber layer obtained in Example 1 after heat treatment. Figure 4 The image shows a photograph and a SEM image of the bonding position between the two electrospun polymer fiber layers (upper film and lower film) obtained in Example 1. Figure 5 The figure shows the stretchability of the bonding position between the two electrospun polymer fiber layers obtained in Example 1. Figure 6 The figure shows the stress curves of the electrospun polymer fiber layer joints and the monolayer PU film after encapsulation in Examples 1 and Comparative Examples 1-2. Figure 7 The diagram shows a schematic of the sensor obtained in Example 2. Figure 8 The diagram shows a comparison of the air permeability performance between the sensor obtained in Example 2 (thermally encapsulated sensor) and the sensor obtained in Comparative Example 3 (spinning sensor). Figure 9 The stability of the sensor obtained in Example 2 is shown in the figure. Detailed Implementation Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments. Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention. Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production. In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process. In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments. In this specification, the numerical range referred to as "value A to value B" refers to the range including endpoint values ​​A and B. The numerical range referred to as "above" and "below" refers to the range including endpoint values. The numerical range referred to as "greater than" and "less than" refers to the range excluding endpoint values. In this specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes both the scenario in which the event occurs and the scenario in which the event does not occur. <Flexible Multilayer Spinning Sensor> The flexible multilayer spun sensor of the present invention includes: an upper electrode layer, a lower electrode layer, and two or more electrospun polymer fiber layers sandwiched between the upper electrode layer and the lower electrode layer, wherein the upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer. The difference between the minimum and maximum values ​​of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is less than 5°C. In the two or more electrospun polymer fiber layers, there is a bonding point A formed by thermal melting between adjacent electrospun polymer fiber layers, there is a bonding point B formed by thermal melting between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, and there is a bonding point C formed by thermal melting between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer. In this invention, there are no particular limitations on the material of the electrospun polymer fiber layer, as long as the polymer fiber layer has flexibility or stretch resilience. For example, in some specific embodiments, the polymer contained in the electrospun polymer fiber layer can be a stretch resilience resin. The term "stretch resilience" means that when the resin is stretched by an external force, it can deform along the direction of the external force, and when the external force is removed, the resin tends to return to its original shape, that is, the resin can exhibit elasticity. In some preferred embodiments, the electrospun polymer fiber layer is formed by electrospinning a thermoplastic stretchable and resilient resin composition comprising a stretchable and resilient resin. There are no particular limitations on the thermoplastic stretchable and resilient resin (i.e., polymer) used in the thermoplastic stretchable and resilient resin composition; for example, it can be polyurethane, polyimide, polyester, silicone, etc. In this invention, the polymers contained in each of the two or more electrospun polymer fiber layers can be the same or different. In some preferred embodiments, from the viewpoint of facilitating the formation of bonding points, the polymers contained in each layer of the electrospun polymer fiber layer are of the same type; that is, the main chains of the polymers contained in each layer of the electrospun polymer fiber layer have similar structural units, or even most of the structural units are of the same type. In some particularly preferred embodiments, the polymers contained in each layer of the electrospun polymer fiber layer are identical. In some preferred embodiments, the thermoplastic stretchable resilient resin composition preferably comprises polyurethane as the thermoplastic stretchable resilient resin. In this case, there is no particular limitation on the proportion of polyurethane in the composition; for example, the proportion of polyurethane relative to 100% by mass of the composition can be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some particularly preferred embodiments, the electrospun polymer fiber layer can be formed by electrospinning polyurethane (e.g., TPU). Besides thermoplastic stretchable and resilient resin, there are no particular restrictions on other components contained in the composition. Various other polymers (such as thermoplastic non-stretchable and resilient resin) and additives (such as toughening agents, colorants, stabilizers, inorganic fillers, heat-resistant additives, aging-resistant additives, UV-resistant additives, antibacterial agents, conductive particles, etc.) can be used. In some preferred embodiments, the individual electrospun polymer fiber layers are identical. In this invention, there are no particular restrictions on the structure of the electrospun polymer fiber layers. Furthermore, the structures of each layer in two or more electrospun polymer fiber layers of this invention can be the same or different. In some preferred embodiments, the thickness of the electrospun polymer fiber layer is preferably 2 to 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 50 μm. In some preferred embodiments, the average diameter of the fibers constituting the electrospun polymer fiber layer is 1 to 5 μm, more preferably 1.5 to 4 μm, and even more preferably 2 to 3 μm. In some preferred embodiments of the present invention, the layers of the electrospun polymer fiber layer are in direct contact with each other, that is, there are no other layers between the layers of the electrospun polymer fiber layer. In this invention, as described above, the bonding points A between adjacent layers of the electrospun polymer fiber layer are formed by thermal melting. There are no particular limitations on the size and number of bonding points A, which can be appropriately adjusted according to the application scenario and material type. In some preferred embodiments, the electrospun polymer fiber layer per square centimeter (cm²) 2 Preferably, the electrospun polymer fiber layer contains 150,000 to 250,000 bonding points A. In other preferred embodiments, the electrospun polymer fiber layer has a density of 150,000 to 250,000 bonding points A per square centimeter (cm²). 2 In the case of ), the area occupied by all the bonding points is preferably less than 10%, more preferably less than 5%. There is no particular limitation on the tensile strength at a single bonding point, which is usually adjusted appropriately according to the material used. In some preferred embodiments, the tensile strength between the two electrospun polymer fiber layers having said bonding point A is preferably 0.1 to 2 N, more preferably 0.2 to 1 N. In some preferred embodiments, the tensile strength between the two electrospun polymer fiber layers having the bonding point A can be more than 70% of the tensile strength of the electrospun polymer fiber layers. In this invention, tensile strength is obtained by stretching the film at a fixed speed of 1 cm / min using a stretching machine until the film at or around the joint begins to break or break. The tensile strength of the electrospun polymer fiber layer was obtained by stretching the film at a fixed speed of 1 cm / min using a stretching machine until the film began to break or break. There are no particular restrictions on the bonding morphology between the layers at bonding point A, which is usually adjusted appropriately according to the materials used. In some preferred embodiments, although bonding point A is formed by thermal melting, it does not destroy most of the fiber state in the adjacent layers at the bonding point. In some more preferred embodiments, at bonding point A, the adjacent electrospun polymer fiber layers are mainly (i.e., more than 50%) interconnected by fibers. In this invention, as described above, the upper electrode layer and / or the lower electrode layer are composite layers comprising a conductive material and a polymer. There are no particular limitations on the specific composition of the upper and lower electrode layers, and they can be appropriately adjusted according to actual needs. In this invention, there are no particular limitations on the conductive material. For example, it can be a carbon material such as graphene, a metallic material such as silver, copper and gold, an electronically conductive polymer material, an ionicly conductive polymer material, etc. In addition, the conductive material can have various forms known in the art, such as particulate or fibrous forms. Furthermore, examples of polymers contained in the upper electrode layer and / or lower electrode layer are the same as those contained in the electrospun polymer fiber layer described above, and will not be repeated here. In this invention, as described above, the difference between the minimum and maximum values ​​of the melting temperature of the polymer contained in each layer of the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is less than 5°C, preferably less than 3°C, more preferably less than 1°C, and particularly preferably 0°C. In some preferred embodiments, the melting temperatures of the polymers contained in each of the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer are substantially the same. In this invention, the term "substantially the same" means that the difference between the compared values ​​is within ±5%. In this invention, the polymers contained in the upper electrode layer and / or the lower electrode layer may be the same as or different from the polymers contained in the electrospun polymer fiber layer. In some preferred embodiments, from the viewpoint of making it easier to achieve the desired melting temperature difference and to form bonding points, the polymers contained in the upper and lower electrode layers and the polymers contained in the electrospun polymer fiber layer are of the same type; that is, the polymers contained in the upper electrode layer, the polymers contained in the lower electrode layer, and the polymers contained in each layer of the electrospun polymer fiber layer have similar structural units in their main chains, or even most of the structural units are similar. In some particularly preferred embodiments, the polymers contained in the upper electrode layer, the polymers contained in the lower electrode layer, and the polymers contained in each layer of the electrospun polymer fiber layer are identical. In addition to conductive materials and polymers, the upper electrode layer and / or lower electrode layer may optionally contain various additives known in the art, such as colorants, stabilizers, toughening agents, inorganic fillers, heat-resistant additives, aging-resistant additives, UV-resistant additives, antibacterial agents, etc. In this invention, there are no particular restrictions on the structure of the upper electrode layer and the lower electrode layer, which can be appropriately adjusted according to actual needs. In some specific implementations, the upper electrode layer and / or the lower electrode layer may be an electrospun polymer fiber layer with at least a portion of its surface coated with a conductive material. In some specific implementations, the upper electrode layer and / or the lower electrode layer can be electrospun polymer fiber layers with conductive materials loaded in the pores. In some specific implementations, the upper electrode layer and / or the lower electrode layer may be solid composite material layers in which conductive substances are dispersed in a polymer matrix. In some specific implementations, the upper electrode layer and / or the lower electrode layer may be an electrospun polymer fiber layer in which a conductive substance is dispersed in a polymer matrix. In some particularly preferred embodiments, the upper electrode layer and / or the lower electrode layer is a silver nanowire / polyurethane (AgNWs / TPU) composite spun fiber membrane. In some preferred embodiments of the present invention, the upper electrode layer and / or the lower electrode layer are each in contact with the outermost surface of the two or more electrospun polymer fiber layers. The term "outermost surface" refers to the outer surface of the air side of the stack formed after two or more electrospun polymer fiber layers are stacked. In this invention, there are no particular restrictions on the manner in which the upper and lower electrode layers exist. The upper and lower electrode layers can each appear as a single integral component or as an array within the sensor. When the electrodes are arranged in an array, the array of upper electrode layers and / or the array of lower electrode layers can be supported on a support layer. When the upper electrode layer and / or the lower electrode layer are each in contact with the outermost surface of the two or more electrospun polymer fiber layers, the support layer is located on the side opposite to the contact surface of the array of upper electrode layers and / or the array of lower electrode layers. In this invention, there are no particular restrictions on the material of the support layer, as long as the support layer does not contain conductive materials. For example, it can be made of the same or different composition as the electrode layer it supports (but does not contain conductive materials). In addition, the structure of the support layer can also be the same as or different from the structure of the electrode layer, for example, it can be an electrospun fiber layer or a solid polymer layer. In this invention, as described above, there is a bonding point B between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, which is formed by thermal melting; and there is a bonding point C between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer, which is formed by thermal melting. The specific details and preferred examples of the resulting bonding points B and C are the same as those of the bonding point A formed between adjacent electrospun polymer fiber layers described above, and will not be repeated here. In addition, in some preferred embodiments, the thickness of the upper electrode layer and its respective layer is preferably 2 to 200 μm, more preferably 5 to 180 μm, and even more preferably 10 to 150 μm. In some preferred embodiments, the sensor of the present invention is a capacitive sensor. In this case, two or more layers of electrospun polymer fibers act as dielectric layers. In some other preferred embodiments, the sensor of the present invention is a piezoelectric sensor. In this invention, there are no particular limitations on the flexible multilayer spinning sensor. In some preferred embodiments, it is prepared by the method described in the "Encapsulation Method of Flexible Multilayer Spinning Sensor" below. <Packaging Method for Flexible Multilayer Spinning Sensors> The packaging method of the flexible multilayer spun fiber sensor of the present invention includes: (1) preparing two or more electrospun polymer fiber layers (sometimes referred to as thin films in this document), an upper electrode layer, and a lower electrode layer, wherein the upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer, and the difference between the minimum and maximum values ​​of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is less than 5°C; (2) sequentially stacking the upper electrode layer, the two or more electrospun polymer fiber layers, and the lower electrode layer to obtain a layer (3) The encapsulation device is placed on the surface of the stack and hot-pressed, thereby forming bonding points in the stack between adjacent electrospun polymer fiber layers, between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, and between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer by thermal melting. When the average value of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer and the melting temperature of the polymer contained in the lower electrode layer is set to T℃, the hot-pressing temperature is a temperature of (T-12) to (T+25)℃. In step (1), there are no particular restrictions on the materials of the electrospun polymer fiber layer, the upper electrode layer, and the lower electrode layer. Specific details and preferred examples are described in the above <Flexible Multilayer Spinning Sensor>, and will not be repeated here. In step (1), there are no particular restrictions on the electrospinning method, and various methods known in the art can be used, which are usually appropriately selected according to the composition of the thermoplastic stretchable resilient resin composition. In some specific implementations, the traction speed of electrospinning can be 60 rpm to 100 rpm. In some specific implementation schemes, the spinning time can be 90 to 150 minutes. In some specific implementations, electrospinning can be carried out using a polymer solution with a mass fraction of 1 to 15%. In step (1), there are no particular restrictions on the preparation methods of the upper electrode layer and the lower electrode layer. They can be obtained by methods known in the art, such as the combined use of blending process and electro-spraying. In step (3), there are no particular restrictions on the material of the packaging equipment, as long as it has excellent thermal conductivity. In some preferred embodiments, the packaging equipment is made of stainless steel. In step (3), the packaging equipment can be a packaging mold or a hot soldering gun. In step (3), in some preferred embodiments, from the viewpoint of both firmly bonding the layers and preserving the fiber structure at each bonding point as much as possible, when the average value of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is set to T℃, the hot pressing temperature is a temperature of (T-12) to (T+25)℃. When the same layer (electrospun polymer fiber layer, upper electrode layer, or lower electrode layer) contains two or more polymers, each polymer is individually included in the calculation of the average melting temperature. In this invention, each melting temperature is determined by differential scanning calorimetry (DSC). In some preferred embodiments, the temperature of the packaging device is raised to a suitable temperature before the packaging device is placed on the surface of the laminate. In step (3), there is no particular limitation on the hot pressing time during encapsulation. In some preferred embodiments, from the viewpoint of both firmly bonding the layers and preserving the fiber structure at each bonding point as much as possible, the hot pressing time is preferably 0.2 to 20 minutes, more preferably 0.5 to 15 minutes. In step (3), thermally fused bonding points are formed through hot pressing. There are no particular restrictions on the bonding points of the electrospun polymer fiber layers; specific details and preferred examples are described in the above-mentioned <Flexible Multilayer Spinning Sensor>, and will not be repeated here. Example The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. <Example 1> A thermal encapsulation process for multilayer electrospun polymer fiber layers ( Figure 1 The encapsulation method in this embodiment specifically includes the following steps: (1) Preparation of electrospun polymer fiber layers: A 5% (w / w) solution of hexafluoroisopropanol (HFIP) for PU (stretchable and resilient TPU, EME-75A, Taiwan Risheng) was prepared. Electrospun flexible fiber films of PU material with a thickness of about 20 μm were fabricated. The melting temperature of PU was analyzed by differential scanning calorimetry (DSC) and found to be 109℃. The DSC measurement was performed as follows: the sample was first heated from 30℃ to 250℃ at a rate of 5℃ / min; then the sample was cooled from 250℃ to 30℃ at a rate of 5℃ / min. The test results were obtained during the cooling process. (2) Place the heat-sealing mold on the hot plate and wait for 10 minutes until the temperature of the sealing mold reaches 115℃. (3) Arrange the two electrospun polymer fiber layers neatly, place the encapsulation mold on the two electrospun polymer fiber layers, and press for 1 minute; the heat-treated spinning will undergo melting changes (such as... Figure 2 and Figure 3 (as shown in the image). After being subjected to heat and pressure treatment, effective links can be formed between the electrospun polymer fiber layers (such as...). Figure 4 As shown), the connection point has high stretchability (e.g. Figure 5 As shown), the tensile strength at the bond between the encapsulated electrospun polymer fiber layers is 0.43 N, and the stress curve is not significantly different from that of the fiber film (as shown). Figure 6 The tensile strength of the combined product is 80% of that of the PU. <Comparative Example 1> Except that the temperature of the encapsulation mold reached 95°C, the heat encapsulation of the multilayer electrospun polymer fiber layer was carried out in the same manner as in Example 1. At a packaging temperature of 95℃, multiple inflection points occurred before reaching the maximum N of 0.43N, indicating insufficient packaging strength and multiple breakages at the interfaces during stretching. This is because the PU film did not reach a sufficiently suitable melting state, failing to establish adhesion between multiple layers. <Comparative Example 2> Except that the temperature of the encapsulation mold reached 135°C, the heat encapsulation of the multilayer electrospun polymer fiber layer was carried out in the same manner as in Example 1. At a packaging temperature of 135℃, the force slope is less than that of the PU film, indicating insufficient packaging strength at the interface. This is because excessively high temperatures can cause uncontrolled liquefaction of the rotating film in the heating zone, resulting in insufficient bonding between the multilayer films. <Example 2> A capacitive sensor array was fabricated using the same encapsulation method as in Example 1. The sensor array consists of four discrete thin films: two TPU fiber films (fabricated as in the preparation of the electrospun polymer fiber layer in Example 1) serve as dielectric layers; the upper electrode layer (an array supported on a support layer) and the lower electrode layer are both composed of silver nanowire / polyurethane (AgNWs / TPU) composite spun films. A schematic diagram of the structure is shown below. Figure 7 As shown in the figure. The polyurethane used to prepare each electrode layer is the same as the polyurethane used for the TPU fiber film. <Comparative Example 3> Two TPU fiber films were prepared as in Example 1, where an electrospun polymer fiber layer was prepared. Additionally, the same upper and lower electrode layers as in Example 2 were prepared. The upper electrode layer, two TPU fiber films, and the lower electrode layer are sequentially bonded together using an adhesive to form a spun sensor. The following tests were conducted on the air permeability and stability of the capacitive sensor arrays obtained in Example 2 and Comparative Example 3. <Breathability> Four experimental groups were placed in a well-ventilated environment at room temperature: sample bottles containing water encapsulated using the sensor prepared in Example 2; sample bottles containing water encapsulated using the conventionally packaged spinning sensor prepared in Comparative Example 3; sample bottles containing water encapsulated using the original caps of the sample bottles; and sample bottles containing water without encapsulation. Each group contained three samples. The initial water volume and sample bottle volume used in each sample were the same. The remaining water content in each sample bottle was measured every 24 hours, and the variance and mean of each group were calculated to evaluate the water evaporation in each experimental group, thereby assessing the air permeability. Generally, the less remaining water, the better the air permeability. Test results are as follows Figure 8 As shown in the image. From Figure 8 As can be seen, after 300 hours of storage, the sensor prepared by the heat-sealing method in Example 2 (with 83.6% remaining water) has better air permeability than the conventionally packaged spinning sensor prepared in Comparative Example 3 (96.1%). <Stability> The sensor prepared in Example 2 was cyclically compressed 1500 times using a compressor station at a speed of 4 N / min and a maximum force of 2.25 N. Test results are as follows Figure 9 As shown in the image. From Figure 9 As can be seen, after 1500 cycles under a pressure of 2.25N, the capacitance change of the sensor prepared by the heat-sealing method in Example 2 is only 5.3%. This demonstrates the excellent stability of the sensor of the present invention. It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto. The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A flexible multilayer spinning sensor, characterized in that it comprises: An upper electrode layer, a lower electrode layer, and two or more electrospun polymer fiber layers sandwiched between the upper electrode layer and the lower electrode layer. The upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer. The difference between the minimum and maximum values ​​of the melting temperatures of the polymers contained in the two or more electrospun polymer fiber layers, the polymers contained in the upper electrode layer, and the polymers contained in the lower electrode layer is less than 5°C. In the two or more electrospun polymer fiber layers, there are bonding points A between adjacent electrospun polymer fiber layers formed by thermal melting. There is a bonding point B between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, formed by thermal melting. There is a bonding point C between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer, which is formed by thermal melting.

2. The flexible multilayer spun sensor according to claim 1, wherein each of the electrospun polymer fiber layers is formed by electrospinning a thermoplastic stretchable and resilient resin composition.

3. The flexible multilayer spun sensor according to claim 2, wherein the thermoplastic stretchable and resilient resin composition comprises polyurethane.

4. The flexible multilayer spun sensor according to any one of claims 1 to 3, characterized in that the thickness of the single-layer electrospun polymer fiber layer is 2 to 100 μm; and / or The average diameter of the fibers constituting the electrospun polymer fiber layer is 1 to 5 μm.

5. The flexible multilayer spun sensor according to any one of claims 1 to 4, characterized in that the tensile strength between the two electrospun polymer fiber layers having the bonding point A can be more than 70% of the tensile strength of a single electrospun polymer fiber layer; and / or At the junction A, the adjacent electrospun polymer fiber layers are mainly connected to each other by fibers.

6. The flexible multilayer spinning sensor according to any one of claims 1 to 5, wherein the upper electrode layer and the lower electrode layer are each independently a composite layer comprising metal fibers and electrospun polymer fibers.

7. The flexible multilayer spun sensor according to any one of claims 1 to 6, wherein the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer are substantially the same.

8. A packaging method for a flexible multilayer spinning sensor, characterized in that, It includes: (1) Prepare two or more electrospun polymer fiber layers, an upper electrode layer, and a lower electrode layer. The upper electrode layer and the lower electrode layer are each independently a composite layer containing a conductive material and a polymer. The difference between the minimum and maximum values ​​of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is less than 5°C. (2) The upper electrode layer, the two or more electrospun polymer fiber layers, and the lower electrode layer are stacked together in sequence to obtain a laminate. (3) The encapsulation device is placed on the surface of the laminate and hot-pressed, thereby forming bonding points in the laminate between adjacent electrospun polymer fiber layers, between the upper electrode layer and the electrospun polymer fiber layer adjacent to the upper electrode layer, and between the lower electrode layer and the electrospun polymer fiber layer adjacent to the lower electrode layer by thermal melting. When the average value of the melting temperature of the polymer contained in the two or more electrospun polymer fiber layers, the melting temperature of the polymer contained in the upper electrode layer, and the melting temperature of the polymer contained in the lower electrode layer is set to T℃, the hot pressing temperature is a temperature of (T-12)~(T+25)℃.

9. The packaging method according to claim 8, characterized in that, The hot pressing time is 0.5 to 20 minutes.

10. The packaging method according to claim 8 or 9, characterized in that, The packaging equipment can be a packaging mold or a hot soldering gun.

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