A flexible pneumatic sensor and its preparation method and application

Abstract

Embodiments of the present invention provide a flexible barometric pressure sensor, a preparation method thereof, and an application thereof, which relate to the field of barometric pressure sensors for aerospace aircraft. The preparation method of the flexible barometric pressure sensor includes using a paraffin / polydimethylsiloxane composite material as the encapsulation layer and the substrate layer structure of the flexible barometric pressure sensor, and sandwiching Mxene with a porous fiber structure therebetween as the conductive medium. By adding an appropriate proportion of paraffin hard particles, the mechanical strength of the polydimethylsiloxane material is improved. At the same time, the paraffin particles in the composite material will undergo a phase change to absorb heat, thereby regulating the overall heat dissipation performance of the device. The flexible barometric pressure sensor prepared in this way can achieve more accurate pressure measurement at special parts of the measured target, has a sensitivity index of 509.5 kPa-1, a minimum detection limit of 1 Pa, and a measurement range of 100 kPa. After testing, it still has high stability during 10,000 loading and unloading cycles.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace vehicle barometric pressure sensors, and more particularly, to a flexible barometric pressure sensor, a preparation method thereof, and an application thereof. Background Art

[0002] Implementing real-time monitoring of key barometric pressure signals on the surface of an aircraft is crucial for ensuring the safety and reliability of the normal operation of the aircraft. The surface pressure signal of the aircraft is an important input guarantee for flight control and structural health monitoring, and is the key to giving full play to the maneuverability of the aircraft and ensuring flight safety. Implementing monitoring of the pressure signals of key structures of the aircraft is of great significance. The flexible barometric pressure sensor is a new type of sensor that uses a sensing circuit conformal integration technology to conformally attach the support circuit of the traditional rigid pressure chip to a complex geometric surface and maintain the original surface, and can realize the health monitoring of the aircraft structure while maintaining the original high performance of the sensor.

[0003] Currently, the more common type of flexible barometric pressure sensor is the piezoresistive pressure sensor, which has the advantages of high sensitivity, wide measurement range, and strong stability. The piezoresistive sensor mainly consists of three parts, namely a vacuum cavity, piezoresistors, and a stress film. The voltage change brought about by the deformation of the stress film under an external pressure stimulus can be used to calculate the resistance change of the piezoresistor, and then the value of the external pressure stimulus signal can be measured.

[0004] Currently, most flexible piezoresistive pressure sensors are prepared by processes such as spin coating, photolithography, vacuum deposition, and dry / wet etching to form complex three-dimensional structures, relying on expensive and complex manufacturing processes. And currently, flexible piezoresistive pressure sensors mostly use materials such as polyimide, polydimethylsiloxane, and polyester as the substrate or encapsulation layer part. These structural components are mostly hydrogel-like structures, with poor structural stability and poor heat dissipation performance, and cannot be applied to the harsh working environment during aircraft monitoring. Summary of the Invention

[0005] According to an embodiment of the present invention, there is provided a flexible barometric pressure sensor, a preparation method thereof, and an application thereof. It solves the problems of complex preparation process, poor structural stability, and difficult heat dissipation of the flexible barometric pressure sensor used for aircraft pressure signal monitoring.

[0006] In a first aspect of the present invention, there is provided a flexible barometric pressure sensor, in which an interdigital electrode, a conductive layer, and an encapsulation layer are sequentially arranged on a substrate layer; the substrate layer and the encapsulation layer are prepared from a paraffin / polydimethylsiloxane composite material.

[0007] Further, the interdigital electrode is an interdigital platinum electrode, an interdigital silver electrode, or an interdigital iron electrode.

[0008] Further, the conductive layer is Mxene porous fiber, graphene or metal.

[0009] In the second aspect of the present invention, a method for preparing a flexible barometric pressure sensor as described in the first aspect above is provided. The method includes:

[0010] S1. Thoroughly mix polydimethylsiloxane and paraffin at 50°C - 90°C, then add a silane coupling agent and stir to mix evenly to obtain a paraffin / polydimethylsiloxane mixture. Then pour it on a flat surface and dry to prepare a paraffin / polydimethylsiloxane composite material;

[0011] S2. Place the paraffin / polydimethylsiloxane composite material at a low temperature of -40°C to -50°C for about 0.5 h - 1 h, then soak it in a conductive material dispersion liquid for 10 s - 20 s, and then anneal it in a vacuum drying chamber to completely evaporate the moisture to obtain a conductive layer and a packaging layer;

[0012] S3. Using the paraffin / polydimethylsiloxane composite material as a substrate layer, prepare interdigital electrodes on it, and attach two copper foils to both ends of the electrodes through platinum paste;

[0013] S4. Finally, place the conductive layer and the packaging layer in step S2 at the center of the interdigital electrodes, and then package the entire structure to obtain a flexible barometric pressure sensor.

[0014] Further, the conductive material dispersion liquid is Mxene porous fiber electrolyte, graphene or metal.

[0015] Further, the material of the interdigital electrodes is platinum, silver or iron. Further, the silane coupling agent is selected from one or more of vinyl silane, amino silane, epoxy silane, mercapto silane or methacryloxy silane.

[0016] In the further described preparation method, the mass ratio of paraffin to polydimethylsiloxane is not less than 1:9, and the mass ratio of the amount of the silane coupling agent added to polydimethylsiloxane is not less than 1:10.

[0017] In the further described preparation method, the mass ratio of paraffin to polydimethylsiloxane is 3:7.

[0018] Further, the concentration of the conductive material dispersion liquid is 0.5 mg / mL - 1.0 mg / mL.

[0019] Further, the concentration of the conductive material dispersion liquid is 0.6 mg / mL.

[0020] Further, the conductive material is Mxene porous fiber electrolyte, and the preparation method of Mxene porous fiber electrolyte is:

[0021] (1) Add LiF to 9M HCl and stir, then add Ti 3 AlC 2 , and continuously stir at 35 °C for more than 24 h; wash the final reaction mixture with deionized water multiple times and centrifuge until the pH value of the supernatant is 6 - 7;

[0022] (2) Then separate Ti 3 C 2 Tx from the unetched Ti 3 AlC 2 , and then perform vacuum filtration to obtain the final Ti 3 C 2 Tx powder; then add the Ti 3 C 2 Tx powder to deionized water and sonicate to obtain a delaminated Ti 3 C 2 Tx dispersion.

[0023] Furthermore, it also includes centrifuging the delaminated Ti 3 C 2 Tx dispersion to remove multi - layer aggregates, and obtaining the supernatant as the Mxene dispersion.

[0024] Furthermore, the S2 annealing is specifically annealing in a vacuum drying chamber at 30 °C - 50 °C for 40 - 60 minutes.

[0025] Furthermore, in S3, the width of the interdigital electrode is 0.8 mm ± 0.1 mm, and the spacing is 0.6 mm ± 0.1 mm.

[0026] In the third aspect of the present invention, a flexible array barometric pressure sensor is provided, which includes a plurality of flexible barometric pressure sensors as described in the first aspect above arranged in an array; the array layout is to arrange a plurality of flexible barometric pressure sensors in a rectangular array, honeycomb or irregular polygon layout.

[0027] In the fourth aspect of the present invention, an application of the flexible barometric pressure sensor as described in the first aspect above in monitoring an aircraft is provided.

[0028] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0029] The flexible barometric pressure sensor provided by the present invention adopts a three-layer structure design. The studied paraffin / polydimethylsiloxane composite material is used as the encapsulation layer and the substrate layer structure of the flexible barometric pressure sensor, and porous fiber-structured Mxene is sandwiched between them as the conductive medium. The interdigital electrodes are prepared on the substrate layer by screen printing, and the preparation method is simple. Compared with the traditional flexible hydrogel substrate, it has better stability and heat dissipation performance, thus making the measurement data more accurate. The mechanical strength of the polydimethylsiloxane material is improved by adding paraffin hard particles, and the elongation rate reaches 30%-50%. When the temperature rises to the melting point of paraffin, the paraffin particles in the composite material will undergo a phase change and absorb heat, thereby regulating the overall heat dissipation performance of the device. The sandwich structure design with the interdigital electrodes sandwiched between the encapsulation layer and the substrate layer enables the flexible barometric pressure sensor to have high sensitivity, a wide pressure range, and fast response / recovery capabilities. Experimental data shows that the flexible barometric pressure sensor provided by the present invention can achieve more accurate pressure measurement at special parts of the measured target, with a sensitivity index of 509.5 kPa -1 -600 kPa -1 and a minimum detection limit of 1 Pa and a measurement range of 0 kPa to 100 kPa. After testing, the stability reaches more than 90% in 10,000 loading and unloading cycles. It should be understood that the content described in the summary of the invention is not intended to limit the key or important features of the embodiments of the present invention, nor to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Combined with the drawings and referring to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present invention will become more obvious. In the drawings, the same or similar reference numerals represent the same or similar elements, where:

[0031] Figure 1 shows a schematic diagram of the three-layer structure of the flexible barometric pressure sensor according to an embodiment of the present invention;

[0032] Figure 2 shows Figure 1 the schematic diagram of the interdigital electrode structure in

[0033] Figure 3 shows a schematic diagram of the total resistance circuit structure according to an embodiment of the present invention;

[0034] Figure 4 shows a schematic diagram of the sensor density array layout scheme according to an embodiment of the present invention;

[0035] Figure 5 shows a curve graph of the relative current and sensitivity parameter changes of the flexible barometric pressure sensor according to an embodiment of the present invention under different external pressures;

[0036] Figure 6 Schematic diagram of the relative current response of the flexible barometric pressure sensor according to an embodiment of the present invention to a 1 Pa pressure under eight - cycle cyclic loading / unloading;

[0037] Figure 7 Schematic diagram of the repeatability test of the flexible barometric pressure sensor according to an embodiment of the present invention in 10,000 loading / unloading cycles (100 kPa).

[0038] Among them, 1 is the substrate layer, 2 is the interdigital electrode, 3 is the connection port, 4 is the conductive layer, and 5 is the encapsulation layer. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] In addition, the term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0041] The preparation of the flexible barometric pressure sensor of the present invention, the specific implementation manners include the preparation of the paraffin / polydimethylsiloxane composite material, the preparation of the porous fibrous Mxene layer, and the overall assembly implementation preparation. The schematic diagram of the three - layer structure of the flexible barometric pressure sensor of the present invention is as Figure 1 shown, 1 is the substrate layer, 2 is the interdigital electrode, 3 is the connection port, 4 is the conductive layer, and 5 is the encapsulation layer.

[0042] Embodiment 1

[0043] A flexible barometric pressure sensor, on which an interdigital electrode 2, a conductive layer 4, and an encapsulation layer 5 are sequentially arranged above the substrate layer 1; the substrate layer is prepared from a paraffin / polydimethylsiloxane composite material, the encapsulation layer is prepared from a paraffin / polydimethylsiloxane composite material, and the mass ratio of paraffin to polydimethylsiloxane is not less than 1:9; the interdigital electrode is an interdigital platinum electrode, an interdigital silver electrode, or an interdigital iron electrode; a connection port 3 is also provided on the electrode for connection with a data acquisition system; the connection port 3 is made of copper foil. The conductive layer is Mxene porous fiber, graphene, or metal.

[0044] 1. Paraffin wax / polydimethylsiloxane composite material, the specific preparation process is as follows:

[0045] (1) Fully mix liquid polydimethylsiloxane organic elastomer (PDMS) and molten paraffin at 50°C to 90°C. The molten paraffin molecules are not soluble in the polydimethylsiloxane organic solvent. Add a curing agent and stir to mix evenly to obtain a milky white paste-like paraffin / polydimethylsiloxane mixture. The mass ratio of paraffin to PDMS is not less than 1:9, and the preferred mass ratio is 3:7. When the mass ratio of paraffin to PDMS is 3:7, the elongation reaches 50%, and the heat dissipation performance and strength are also optimal. The mass ratio of the amount of curing agent added to PDMS is not less than 1:10, and the preferred mass ratio is 1:5.

[0046] The curing agent is a silane coupling agent, which can be selected from one or more of vinyl silane, amino silane, epoxy silane, mercapto silane or methacryloxy silane.

[0047] (2) Pour the paraffin wax / polydimethylsiloxane mixture in a paste form onto a flat glass substrate and bake it in an oven at 50°C to 60°C for 2 hours to induce cross-linking, thereby preparing a paraffin wax / polydimethylsiloxane composite material with an encapsulation layer thickness of 1 mm to 3 mm and a substrate layer thickness of 1 mm to 2 mm. The temperature can be 50°C to 60°C, and the baking time is not less than 1.5 hours.

[0048] 2. The porous fibrous Mxene layer, the specific preparation process is as follows:

[0049] (1) First, add 0.8 g LiF into 10 mL 9 M HCl and stir for 5 min. Then add 0.5 g Ti 3 AlC 2 The powder was gradually dissolved in the above mixture for 5 min and stirred continuously at 35°C for 24 h; the final reaction mixture was centrifuged and washed several times with deionized water and centrifuged (3500 rpm) until the pH value of the supernatant reached 6.

[0050] (2) Then the black slurry (Ti 3 C 2 Tx) and gray solid (unetched Ti 3 AlC 2 ) separation, followed by vacuum filtration on porous polytetrafluoroethylene to obtain the final Ti 3 C 2 Tx powder.

[0051] (3) In order to obtain delaminated Ti 3 C 2 The dispersion of Tx sheets was mixed with 0.1 g Ti 3 C 2The Tx powder was added to 100 mL of deionized water and sonicated for several minutes.

[0052] (4) Next, the dispersion was centrifuged at 3500 rpm for 30 minutes to remove the multi-layer aggregates. The resulting supernatant was saved for further use or identification. The Mxene dispersion used in the present invention is in the range of 0.5 mg / mL to 1.0 mg / mL. After multiple tests, a concentration of 0.6 mg / mL is preferred because it can balance low sheet resistance, low power consumption, and high sensitivity. After the identification and detection are completed, the Mxene dispersion is synthesized.

[0053] The porous fibrous Mxene can be prepared by existing technologies, or directly using commercially available products, or prepared by the preparation method provided by the present invention. The preparation method of the porous fibrous Mxene provided by the present invention is relatively simple compared with the existing technologies. In commercial applications, the cost is obviously lower.

[0054] 3. The overall assembly preparation process is as follows:

[0055] (1) First, on the top of a paraffin / polydimethylsiloxane composite material with a size of 15 mm × 10 mm as the substrate layer, interdigital platinum electrodes with a width of 0.8 mm and a spacing of 0.6 mm were fabricated using platinum paste through screen printing technology. Two copper foils were attached to both ends of the electrodes using platinum paste for electrical connection to the data acquisition system, as Figure 2 shown. In some embodiments, the width and spacing of the interdigital platinum electrodes can float within the range of ±0.1 mm.

[0056] In some embodiments, the platinum electrodes of the substrate can be replaced with other electrode materials that are easier to prepare and have stronger conductivity, such as silver and iron.

[0057] (2) Then, the paraffin / polydimethylsiloxane composite material was placed at a low temperature of -40°C to -50°C for about 0.5 h - 1 h, cut into a rectangle of 10 mm × 10 mm, and soaked in the Mxene dispersion for 10 s. Then, it was annealed in a vacuum drying chamber at 40°C for 40 minutes to completely evaporate the moisture, obtaining a conductive layer and an encapsulation layer (paraffin / polydimethylsiloxane composite material). The low temperature of -40°C to -50°C can be achieved by placing the composite material sample in a temperature-variable box with liquid nitrogen freezing function and maintaining the temperature in the box at -40°C to -50°C for about 0.5 h - 1 h to realize the freezing hardening of the sample.

[0058] (3) After placing the conductive layer and the encapsulation layer (paraffin / polydimethylsiloxane composite material) at the center of the interdigital electrodes, the entire structure was encapsulated to produce a flexible pressure sensor. The encapsulation can adopt the method of three-dimensional mechanical guided assembly, and the substrate layer and the encapsulation layer were mechanically assembled through a hot press and a fat-soluble tape.

[0059] The total resistance of the flexible barometric pressure sensor is the sum of the electrode resistance (R e ), the resistance of the conductive layer (R b ), and the contact resistance between the conductive layer and the electrode (R c ), and the specific circuit schematic is as shown in Figure 3 . When pressure is applied, since the gap between the conductive layer and the electrode is compressed, the Mxene nanosheets approach each other to increase the conductive path. When the pressure is further increased, the contact area between the conductive layer and the interdigital electrode also increases to reduce the contact resistance. Therefore, this flexible barometric pressure sensor exhibits high sensitivity in a wide pressure range. The Mxene with a porous fiber structure as the conductive medium can be replaced with other conductive structures such as graphene, metals, etc. to achieve greater sensitivity measurement and structural strength stability.

[0060] Example 2

[0061] The flexible barometric pressure sensor prepared in Example 1 was tested under different external pressures, and the changes in its relative current and sensitivity parameters are as shown in Figure 5 . Due to its highly porous 3D structure, this flexible barometric pressure sensor has ultra-high sensitivity in a wide pressure range (0.5 kPa - 100 kPa). When the pressure increases from 0.5 kPa to 100 kPa, the current response increases in a piecewise linear manner. In the pressure ranges of 0.5 kPa - 10 kPa, 10 kPa - 30 kPa, and 30 kPa - 100 kPa, the sensitivities S 1 , S 2 , S 3 are 509.5 kPa -1 , 179.4 kPa -1 , and 53.7 kPa -1 , respectively. Especially in the pressure range of 0.5 kPa - 10 kPa, the ultra-high sensitivity of 509.5 kPa -1 is very important for detecting the pressure monitoring signal on the surface of the aircraft.

[0062] In addition to large pressures, this flexible barometric pressure sensor can also detect a tiny pressure of 1 Pa, as shown in Figure 6 . A load of 0.1 N was applied to a sample of 0.010 g (acceleration unit), and the sample area was 0.1 m 2 , indicating that the minimum detectable limit pressure is 1 Pa. In addition, the performance of this flexible barometric pressure sensor is very stable and reliable, and the relative current response to a pressure of 1 Pa is basically the same under eight cycles of cyclic loading / unloading. The repeatability test results are as shown in Figure 7As shown, even after 10,000 loading / unloading cycles at different pressure values of 10 kPa, 30 kPa, and 100 kPa, the relative current change remains almost unchanged, indicating that the flexible barometric pressure sensor of the present invention has extremely high stability performance, with a stability reaching more than 90%. This is of great significance for monitoring the pressure signals of key structures of aircraft, ensuring the accurate input of surface pressure signals of aircraft, giving full play to the maneuverability of aircraft, and ensuring flight safety.

[0063] Example 3

[0064] The single flexible barometric pressure sensor of Example 2 is configured into a flexible array barometric pressure sensor according to layouts such as rectangular arrays, honeycombs, or irregular polygons. By replacing the main array sensor with a secondary array sensor, a flexible sensing network capable of effectively monitoring the pressure distribution at key positions in the space of the aircraft can be formed. More accurate measurement data can be obtained, and waste of data acquisition resources can be avoided.

[0065] A single flexible barometric pressure sensor is configured into an array layout for detecting the spatial pressure distribution.

[0066] Preferably, as Figure 4 shown, the main array uses a 4×4 flexible barometric pressure sensor array unit in a finger-shaped combined electrode matrix. Among the four sub-flexible barometric pressure sensors at the pressure center, a 4×4 sub-array is still used, which can save data acquisition resources while having more accurate sensitivity in spatial measurement compared to the sensors of a single-pole array. Other matrix array layouts can also be adopted. Figure 4 The smallest size in the middle is 10 mm×10 mm.

[0067] In some embodiments, the above array layout can be optimized, such as using layout structures such as honeycombs and irregular polygons to improve the structural stability of the device and the utilization rate of the internal space.

[0068] As another embodiment of the present invention, an application of the flexible barometric pressure sensor as described in Example 1 above in monitoring an aircraft is provided.

[0069] According to the embodiments of the present invention, a paraffin / polydimethylsiloxane composite material is used as the encapsulation layer and the substrate layer structure of the flexible barometric pressure sensor, and Mxene with a porous fiber structure is sandwiched therein as the conductive medium. The mechanical strength of the polydimethylsiloxane material is improved by adding paraffin hard particles in an appropriate proportion. When they are added in the proportion studied in the present invention, when the temperature rises to the melting point of paraffin, the paraffin particles in the composite material will undergo a phase change and absorb heat, thereby regulating the overall heat dissipation performance of the device. In addition, by configuring a single flexible sensor into an array layout and replacing the main array sensor with a secondary array sensor, accurate measurement data can be obtained, and waste of data acquisition resources can be avoided.

[0070] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flexible air pressure sensor, comprising a substrate layer (1), characterized in that: On the substrate layer (1), interdigitated electrodes (2), a conductive layer (4) and a packaging layer (5) are sequentially arranged; the substrate layer (1) is made of a paraffin wax / polydimethylsiloxane composite material, and the packaging layer (5) is made of a paraffin wax / polydimethylsiloxane composite material; the paraffin wax / polydimethylsiloxane composite material is placed at a low temperature of -40°C to -50°C for about 0.5h-1h, then immersed in a conductive material dispersion for 10s-20s, and then placed in a vacuum drying chamber for annealing to completely evaporate the water, thereby obtaining a conductive layer and a packaging layer.

2. The flexible air pressure sensor according to claim 1, characterized in that: The mass ratio of paraffin wax to polydimethylsiloxane is not less than 1:

9.

3. The flexible air pressure sensor according to claim 1, characterized in that: The conductive layer is MXene porous fiber electrolyte, graphene or liquid metal.

4. A method for preparing a flexible air pressure sensor, used for preparing the flexible air pressure sensor as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises: The polydimethylsiloxane and paraffin are fully mixed at 50°C to 90°C, and a silane coupling agent is added and stirred to mix evenly to obtain a paraffin / polydimethylsiloxane mixture, which is then poured onto a flat surface and dried to prepare a paraffin / polydimethylsiloxane composite material; The paraffin wax / polydimethylsiloxane composite material is placed at a low temperature of -40°C to -50°C for about 0.5h-1h, then immersed in a conductive material dispersion for 10s-20s, and then placed in a vacuum drying chamber for annealing to completely evaporate the water, thereby obtaining a conductive layer and a packaging layer; The paraffin wax / polydimethylsiloxane composite material was used as the substrate layer, on which the interdigitated electrodes were prepared, and two copper foils were attached to the two ends of the electrodes through platinum paste; A conductive layer and a packaging layer are placed at the center of the interdigitated electrodes to package the entire structure to obtain a flexible pressure sensor.

5. The preparation method according to claim 4, characterized in that: The concentration of the conductive material dispersion is 0.5mg / mL-1.0mg / mL.

6. The preparation method according to claim 4, characterized in that: The conductive material dispersion is a Mxene porous fiber electrolyte, and its preparation method is as follows: (1) LiF was added to 9M HCl and stirred, and then Ti3AlC2 was added and stirred continuously at 35°C for more than 24 hours; the final reaction mixture was washed with deionized water for multiple times and centrifuged until the pH value of the supernatant was 6-7; (2) Ti3C2Tx is then separated from the unetched Ti3AlC2, followed by vacuum filtration to obtain the final Ti3C2Tx powder; the Ti3C2Tx powder is then added to deionized water and ultrasonicated to obtain a delaminated Ti3AlC2 dispersion.

7. The preparation method according to claim 4, characterized in that: The annealing comprises: Anneal in a vacuum drying chamber at 30-50°C for 40-60 minutes.

8. The preparation method according to claim 4, characterized in that: The width of the interdigital electrodes is 0.8 mm ± 0.1 mm, and the spacing is 0.6 mm ± 0.1 mm.

9. A flexible array air pressure sensor, characterized in that: It comprises a plurality of flexible air pressure sensors as described in any one of claims 1 to 3 arranged in an array; the arrangement in an array is to arrange the plurality of flexible air pressure sensors in a rectangular array, a honeycomb or an irregular polygon.

10. Use of the flexible air pressure sensor according to any one of claims 1 to 3 in monitoring an aircraft.

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