Flexible patch-type sensor for wide-temperature-range air pressure monitoring, preparation method and application thereof

Abstract

This invention discloses a flexible patch sensor for wide-temperature-range air pressure monitoring, its fabrication method, and its application. The method includes preparing modified silicone rubber and dielectric materials, fabricating a structured dielectric layer using a structure transfer printing process, printing an electrode layer and a sealing layer on a flexible substrate, placing the structured dielectric layer in a sealed cavity, aligning it with another electrode-sealing layer, and then bonding and encapsulating it into a air pressure sensing patch using oxygen plasma treatment. This invention introduces a sealed cavity inside the sensor, enabling wide-range air pressure sensing with both positive and negative pressures; the introduction of modified silicone rubber and dielectric materials ensures stable operation of the sensor over a wide temperature range. This invention solves the challenges of wide-range, wide-temperature-range, and non-invasive continuous monitoring of wind pressure on aircraft surfaces, providing an innovative solution for real-time monitoring of wind pressure across all areas of aerospace applications.

Description

Technical Field

[0001] This invention relates to a flexible capacitive pressure sensing patch for monitoring air pressure on the surface of aircraft and its preparation method, belonging to the cutting-edge interdisciplinary manufacturing technology of aerospace and flexible electronics. Background Technology

[0002] Aeronautical wind pressure testing technology is a key technology in the aviation field, playing a crucial role in optimizing aircraft aerodynamic shape, measuring aerodynamic loads, and determining lift and drag. Unlike contact pressure testing in other fields such as robotics and wearable medical devices, wind pressure testing requires measuring non-contact loads ranging from -100 kPa to +100 kPa because the static pressure on the wing surface of an aircraft during flight exists in both positive and negative pressure zones. Traditional wind pressure testing techniques include pressure-sensing holes and pressure-sensitive paint. The former involves piercing small holes in the wing or fuselage and connecting a pressure sensor through a thin tube. This method is invasive, making it difficult to install sensors across the entire wing area, especially in critical locations such as the trailing edge. Another technique involves spraying pressure-sensitive luminescent materials onto a model surface and recording the color using a camera. However, this method suffers from poor resolution and performance instability under varying lighting conditions. Flexible sensors can perfectly conform to the curved surfaces of an aircraft, allowing for wing surface wind pressure measurement without altering the aircraft's structure or surrounding flow conditions, and providing real-time feedback. This represents an ideal solution for aeronautical pressure testing technology.

[0003] However, achieving high-quality monitoring of wind pressure on aircraft surfaces faces significant technical challenges: 1) The wind pressure amplitude distribution on aircraft surfaces is wide, ranging from 100 kPa to +100 kPa. Therefore, the sensor's range needs to meet both positive and negative pressure requirements while also possessing high resolution; 2) During flight, aircraft undergo multiple processes such as takeoff, climb, cruise, descent, and landing. The surface temperature of the aircraft is obviously different in each process. During takeoff, the wing surface heats up due to friction with the airflow. However, when climbing to an altitude of 10,000 meters, the wing surface becomes cold due to the drop in ambient temperature. This requires the flexible patch to operate stably within a wide temperature range of -70℃ to +140℃, a condition that current flexible sensors used for air pressure measurement cannot meet. Therefore, developing a flexible sensor that can simultaneously meet the requirements of wide-range positive and negative pressure measurement and stable operation over a wide temperature range is a key prerequisite for promoting flexible sensing from the laboratory to aerospace applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies for monitoring wind pressure on aircraft surfaces, such as invasive installation, inability to monitor the entire area, and narrow operating temperature range, this invention aims to provide a flexible, wide-temperature-range capacitive pressure sensing patch for monitoring air pressure on aircraft surfaces and its fabrication method. By introducing modified silicone rubber and dielectric units, the sensor is ensured to operate stably over a wide temperature range, enabling real-time wind pressure monitoring over a wide range and temperature range when the flexible patch is attached to the aircraft surface.

[0005] The present invention is achieved through the following technical solution.

[0006] In one aspect, this invention provides a method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring, comprising the following steps: Step 1, Prepare the top of the sensor: a. Print the top electrode layer: Align the polyimide (PI) film with the electrostatic sheet film and adsorb it onto the electrostatic sheet film; A top silver paste electrode was printed on a polyimide (PI) film according to the electrode structure. The printed silver paste electrode is heated and cured to obtain a fully cured top electrode layer on the PI film; b. Print the top sealing layer: Modified silicone rubber preform was printed on the electrode layer of the PI film according to the sealing layer structure; The printed modified silicone rubber SR pre-formed liquid is heated and cured to obtain a fully cured modified silicone rubber top sealing layer on the PI film; Step 2, Prepare the bottom of the sensor: a. Applying the bottom electrode layer: Align the polyimide (PI) film with the electrostatic sheet film and adsorb it onto the electrostatic sheet film; Print the bottom silver paste electrode on the polyimide (PI) film according to the electrode structure; The printed silver paste electrode is heated and cured to obtain a fully cured bottom electrode layer on the PI film; b. Print the bottom sealing layer: Modified silicone rubber SR preform was printed on the electrode layer of the PI film according to the sealing layer structure. The printed modified silicone rubber SR pre-formed liquid is heated and cured to obtain a fully cured modified silicone rubber bottom sealing layer on the PI film. Step 3, Sensor Packaging: The top and bottom of the prepared sensor were treated with oxygen plasma. Align the dielectric layer and place it on the bottom electrode layer; Align the top and bottom of the sensor for encapsulation, and peel off the electrostatic film on one side of the PI film to obtain a flexible patch sensor.

[0007] According to an exemplary embodiment of the present invention, the modified silicone rubber preform is prepared according to the following method: The polydimethylsiloxane (PDMS), elastomer curing agent, and vinylmethylsiloxane-dimethylsiloxane copolymer (VMQ) were mixed and stirred in a mass ratio of (90~100):(8~10):(5~20).

[0008] According to an exemplary embodiment of the present invention, the elastomer curing agent includes platinum hydrochloride, propylsilane, hydrogen-containing silicone oil, or dicumyl peroxide.

[0009] According to an exemplary embodiment of the present invention, the dielectric layer is prepared according to the following method: a. Mix and stir the modified silicone rubber prepreg with carbon nanotubes at a mass ratio of (90~100):(1~7.5) to obtain dielectric layer silicone rubber / carbon nanotube prepreg. b. A positive mold is prepared by 3D printing, which is then cast with polydimethylsiloxane (PDMS), heated and cured, and then demolded to obtain a negative mold. A pre-formulated dielectric layer of silicone rubber / carbon nanotubes is then cast onto the negative mold, heated and cured, and then demolded to obtain a structured dielectric layer.

[0010] According to an exemplary embodiment of the present invention, the structured dielectric layer is a circle with a diameter smaller than that of the top electrode layer, the top sealing layer, the bottom sealing layer, and the bottom electrode layer, which is laser-cut.

[0011] According to an exemplary embodiment of the present invention, in steps 1 and 2, silver electrodes are printed with a line width of 0.20~0.21mm, a printing height of 0.15~0.16mm, a unit ink output of 1.00~1.10ml / min, and a continuous ink output of 0.20~0.30ml / min; Heat the printed silver paste electrode at 60-80℃ for 30-40 minutes.

[0012] According to an exemplary embodiment of the present invention, a modified silicone rubber preform is printed with a line width of 0.20~0.21mm, a printing height of 0.15~0.16mm, a unit ink output of 1.00~1.10ml / min, and a continuous ink output of 0.20~0.30ml / min. After printing the modified silicone rubber preform, heat it at 100~120℃ for 100~120 minutes to cure.

[0013] According to an exemplary embodiment of the present invention, the oxygen plasma treatment power is 30-40% and the duration is 30-40 seconds.

[0014] Another aspect of the present invention provides a flexible patch sensor for wide-temperature-range air pressure monitoring prepared by the method described above, comprising a top encapsulation layer, a top electrode layer, a top sealing layer, a dielectric layer, a bottom sealing layer, a bottom electrode layer, and a bottom encapsulation layer distributed from top to bottom. The top encapsulation layer is bonded to the top electrode layer and the top sealing layer, and the other side of the top electrode layer is bonded to the top sealing layer; the bottom encapsulation layer is bonded to the bottom electrode layer and the bottom sealing layer, and the other side of the bottom electrode layer is bonded to the bottom sealing layer; the other side of the top sealing layer is bonded to the bottom sealing layer by plasma treatment; the dielectric layer is located within the sealed cavity formed by the top electrode layer, the top sealing layer, the bottom sealing layer and the bottom electrode layer.

[0015] The present invention, by adopting the above technical solution, has the following beneficial effects: 1. Based on the principle of non-contact load monitoring: changes in external air pressure lead to pressure difference, deformation, and changes in electrical signal. A flexible capacitive barometric pressure sensor with a wide range of positive and negative pressure is proposed. Dielectric units are fabricated using structural transfer printing technology. Electrode layers and sealing layers of the sensor are fabricated using dispensing printing technology. The sensor is sealed using plasma encapsulation technology, and a sealed cavity is introduced inside the sensor to ensure the sensor's ability to measure a wide range of barometric loads.

[0016] 2. By introducing vinylmethylsiloxane-dimethylsiloxane copolymer VMQ into polydimethylsiloxane PDMS to adjust the distance of molecular chain segments after curing, a modified silicone rubber material was prepared. Compared with traditional dimethylsiloxane PDMS, the modified silicone rubber SR has better low-temperature resistance.

[0017] 3. Dielectric materials were prepared by incorporating carbon nanotubes into silicone rubber, and dielectric units resistant to high and low temperatures were fabricated. By introducing modified silicone rubber and dielectric materials, the sensor was able to operate stably over a wide temperature range.

[0018] 4. The flexible patch proposed in this invention can perfectly fit the curved surface of an aircraft, enabling the measurement of wind pressure on the aircraft wing surface without altering the aircraft's own structure or the surrounding flow field conditions, and providing real-time feedback. This provides a novel solution for wide-range, wide-temperature-range, and attachable air pressure measurement in real-time monitoring of wind pressure on the surface of aerospace vehicles. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is an exploded view of the flexible patch sensor structure for wide-temperature-range air pressure monitoring according to the present invention. Figure 2This is a schematic diagram of the measurement principle of the flexible capacitive barometric pressure sensor unit of the present invention; Figure 3 This is a flowchart illustrating the fabrication process of the flexible capacitive barometric pressure sensor of this invention. Figure 4 This is a flowchart of the fabrication process of the structured dielectric unit of the present invention; Figure 5 This is a schematic diagram of the modified silicone rubber design of this invention; Figure 6 These are the cyclic compression curves of the unmodified and modified silicone rubbers of this invention at low temperatures; Figure 7 This is the pressure response curve and minimum detection limit diagram of the flexible capacitive barometric pressure sensor of the present invention; Figure 8 This is a low-temperature cyclic load test diagram of the flexible capacitive barometric pressure sensor of the present invention without the introduction of modified silicone rubber and dielectric materials; Figure 9 These are the low-temperature, room-temperature, and high-temperature long-term cyclic load test diagrams of the flexible capacitive barometric pressure sensor of this invention. Figure 10 This is a schematic diagram of the flexible capacitive barometric pressure sensor array of the present invention attached to a wing model; Figure 11 This is a comparison chart of the results of the flexible capacitive barometric pressure sensor of this invention and the wind tunnel test results of a bit tube. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0021] refer to Figure 1 As shown, this invention discloses a flexible patch-type sensor for wide-temperature-range pressure monitoring, comprising, from top to bottom, a top encapsulation layer 1, a top electrode layer 2, a top sealing layer 3, a dielectric layer 4, a bottom sealing layer 5, a bottom electrode layer 6, and a bottom encapsulation layer 7. The top encapsulation layer 1 is bonded to the top electrode layer 2 and the top sealing layer 3, and the other side of the top electrode layer 2 is bonded to the top sealing layer 3; the bottom encapsulation layer 7 is bonded to the bottom electrode layer 6 and the bottom sealing layer 5, and the other side of the bottom electrode layer 6 is bonded to the bottom sealing layer 5; the other side of the top sealing layer 3 is bonded to the bottom sealing layer 5 via plasma treatment; the dielectric layer 4 is located within a sealed cavity formed by the top electrode layer 2, the top sealing layer 3, the bottom sealing layer 5, and the bottom electrode layer 6.

[0022] refer to Figure 2As shown, the working principle of the flexible sensing patch for wide-temperature-range air pressure monitoring in this invention is as follows: When the bottom encapsulation layer 7 is attached to the wing surface or wing model, when a positive pressure load 8 is applied, the external pressure is greater than the internal sealing cavity pressure, causing the top encapsulation layer 1 and the top electrode layer 2 to deform downwards, reducing the distance between the top electrode layer 2 and the bottom electrode layer 6, thereby increasing the capacitance signal; when a negative pressure load 9 is applied, the external pressure is less than the internal sealing cavity pressure, causing the top encapsulation layer 1 and the top electrode layer 2 to deform upwards, increasing the distance between the top electrode layer 2 and the bottom electrode layer 6, thereby decreasing the capacitance signal (the capacitance value of a parallel plate capacitor is inversely proportional to the distance between the plates).

[0023] refer to Figure 3 As shown, this embodiment of the invention provides a method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring, comprising the following steps: Step 1, Prepare the top of the sensor: 11) Prepare a size of 10×8cm 2 A 15µm thick polyimide (PI) film and a size of 10×8cm 2 One electrostatic film and one PI film are attached to the electrostatic film, and the PI film is aligned and adsorbed onto the electrostatic film. See [the diagram]. Figure 3 a; 12) Place the PI film, fixed by an electrostatic film, on the dispensing machine platform. Print the top silver paste electrode according to the designed electrode structure. The printing parameters for the silver electrode are: line width 0.20~0.21mm, printing height 0.15~0.16mm, unit ink output 1.00~1.10ml / min, and continuous ink output 0.20~0.30ml / min. Heat the printed silver paste electrode at 60~80℃ for 30~40min. This yields the top electrode layer 2, with fully cured silver on the top encapsulation layer 1 of the PI film. (See...) Figure 3 b; 13) Print the top silicone rubber sealing layer. According to the designed sealing layer structure, print the prepared modified silicone rubber pre-formulated liquid onto the electrode layer; place the printed silicone rubber pre-formulated liquid in an environment of 100~120℃ and heat for 100~120 min to cure, obtaining the fully cured top sealing layer 3 on the PI film, see... Figure 3 c.

[0024] The modified silicone rubber preform is prepared according to the following method: Polydimethylsiloxane (PDMS), elastomer curing agent, and vinylmethylsiloxane-dimethylsiloxane copolymer (VMQ) were mixed in a mass ratio of (90~100):(8~10):(5~20) and stirred magnetically for 24~48 hours until homogeneous to prepare modified silicone rubber (SR) preform.

[0025] The elastomer curing agents include platinum hydrochloride, silane, hydrogen-containing silicone oil, or dicumyl peroxide.

[0026] Step 2, Prepare the bottom of the sensor: 21) Prepare a size of 10×8cm 2 A 15µm thick polyimide (PI) film and a size of 10×8cm 2 One electrostatic film and one PI film are attached to the electrostatic film, and the PI film is aligned and adsorbed onto the electrostatic film. See [the diagram]. Figure 3 a; 22) Place the PI film, fixed by an electrostatic film, on the dispensing machine platform and print the bottom silver paste electrode according to the designed electrode structure. Print the silver electrode with the following parameters: line width 0.20~0.21mm, printing height 0.15~0.16mm, unit ink output 1.00~1.10ml / min, and continuous ink output 0.20~0.30ml / min. Heat the printed silver paste electrode at 60~80℃ for 30~40min. This yields the bottom electrode layer 6 with fully cured silver on the bottom encapsulation layer 7 of the PI film. (See...) Figure 3 d; 23) Printing the bottom modified silicone rubber sealing layer: Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; the printing parameters are: line width 0.20~0.21mm, printing height 0.15~0.16mm, unit ink output 1.00~1.10ml / min, continuous ink output 0.20~0.30ml / min; place the printed silicone rubber pre-formulated liquid in an environment of 100~120℃ and heat for 100~120min to cure, to obtain the fully cured bottom sealing layer 5 on the PI film, see Figure 3 e.

[0027] Step 3, Sensor Packaging: 31) The top and bottom of the prepared sensor are treated with oxygen plasma at a power of 30-40% for 30-40 seconds. 32) Align and place the pre-prepared structured dielectric layer 4 onto the bottom electrode layer 6, see... Figure 3 f; 33) Align the top and bottom of the sensor and seal it. Peel off the electrostatic film from one side of the PI film to obtain the final sensor. See [link to documentation]. Figure 3 g.

[0028] The structured dielectric layer is prepared according to the following method: a. Preparation of dielectric layer silicone rubber / carbon nanotube preform solution The modified silicone rubber prepreg and carbon nanotubes were mixed at a mass ratio of (90~100):(1~7.5) and stirred magnetically for 24~48 hours to obtain the dielectric layer silicone rubber / carbon nanotube prepreg. b. Fabrication of structured dielectric layers using a molding method refer to Figure 4 As shown, a positive mold of the designed structure is first prepared using 3D printing technology. Figure 4 a; then cast with the soft material polydimethylsiloxane (PDMS), see Figure 4 b; After heat curing, demold to obtain the "negative mold" of the structure, see Figure 4 c; The dielectric layer prepreg prepared in S2 is poured onto the "vacuum mold", see Figure 4 d; After heat curing, demold to obtain a structured dielectric layer, see Figure 4 e; Subsequently, the dielectric layer units of the required size are cut using laser cutting. The laser-cut dielectric layer is a circle with a diameter smaller than that of the top electrode layer, top sealing layer, bottom sealing layer, and bottom electrode layer. See Figure 4 f.

[0029] The fabrication of the sensor of the present invention will be further illustrated below through different embodiments.

[0030] Example 1 Step 1, Prepare the top of the sensor: 11) Align and adsorb the PI film onto the electrostatic film; 12) On the PI film fixed by the electrostatic sheet, print the top silver paste electrode according to the designed electrode structure. The line width is 0.20 mm, the printing height is 0.15 mm, the unit ink output is 1.10 ml / min, and the continuous ink output is 0.25 ml / min. Heat the printed silver paste electrode at 70℃ for 35 min to obtain a top electrode layer with completely cured silver on the PI film encapsulation layer; 13) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; place the printed silicone rubber pre-formulated liquid in an environment of 100℃ and heat for 120 min to cure, so as to obtain a fully cured top sealing layer on the PI film.

[0031] The modified silicone rubber preform is prepared according to the following method: PDMS, cyclohexane, silane, hydrogen-containing silicone oil or diisopropylbenzene peroxide, and VMQ were mixed at a mass ratio of 90:8:10 and magnetically stirred for 36 hours to obtain a modified silicone rubber (SR) preform.

[0032] Step 2, Prepare the bottom of the sensor: 21) Align and adsorb the PI film onto the electrostatic film; 22) On the PI film fixed by the electrostatic sheet, print the bottom silver paste electrode according to the designed electrode structure. The line width is 0.21 mm, the printing height is 0.15 mm, the unit ink output is 1.10 ml / min, and the continuous ink output is 0.30 ml / min. Heat the printed silver paste electrode at 80℃ for 30 min to obtain the bottom electrode layer with completely cured silver on the bottom encapsulation layer of the PI film. 23) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; the line width is 0.21 mm, the printing height is 0.15 mm, the unit ink output is 1.00 ml / min, and the continuous ink output is 0.25 ml / min; place the printed silicone rubber pre-formulated liquid in an environment of 110℃ and heat for 110 min to cure, so as to obtain a fully cured bottom sealing layer on the PI film.

[0033] Step 3, Sensor Packaging: 31) The top and bottom of the prepared sensor were treated with oxygen plasma at 40% power for 30 seconds. 32) Align and place the pre-prepared structured dielectric layer onto the bottom electrode layer; 33) Align the top and bottom of the sensor and seal them together. Peel off the electrostatic film on one side of the PI film to obtain the final sensor.

[0034] The structured dielectric layer is prepared according to the following method: a. Preparation of dielectric layer silicone rubber / carbon nanotube preform: The modified silicone rubber prepreg and carbon nanotubes were mixed at a mass ratio of 95:7.5 and magnetically stirred for 36 hours to obtain the dielectric layer silicone rubber / carbon nanotube prepreg. b. Fabrication of structured dielectric layers using a molding method The "positive mold" of the structure is prepared by 3D printing technology, and then cast with polydimethylsiloxane (PDMS). After heating and curing, the mold is demolded to obtain the "negative mold" of the structure. The dielectric layer pre-formed liquid is poured onto the "negative mold", heated and cured, and then demolded to obtain the structured dielectric layer. The dielectric layer units of the required size are then cut by laser cutting.

[0035] The obtained flexible capacitive barometric pressure sensor was calibrated. The flexible barometric pressure sensor in this embodiment has a wide range of -90kPa to +100kPa and can work stably in a temperature range of -65℃ to +130℃.

[0036] Example 2 Step 1, Prepare the top of the sensor: 11) Align and adsorb the PI film onto the electrostatic film; 12) On the PI film fixed by the electrostatic sheet, print the top silver paste electrode according to the designed electrode structure. The line width is 0.21 mm, the printing height is 0.15 mm, the unit ink output is 1.00 ml / min, and the continuous ink output is 0.30 ml / min. Heat the printed silver paste electrode at 80℃ for 30 min to obtain a top electrode layer with completely cured silver on the PI film encapsulation layer; 13) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; place the printed silicone rubber pre-formulated liquid in an environment of 110℃ and heat for 110 min to cure, so as to obtain a fully cured top sealing layer on the PI film.

[0037] The modified silicone rubber preform is prepared according to the following method: PDMS, cyclohexane curing agent, propylsilane, hydrogen-containing silicone oil or diisopropylbenzene peroxide, and vinylmethylsiloxane-dimethylsiloxane copolymer VMQ were mixed at a mass ratio of 100:9:20 and magnetically stirred for 48 hours to obtain modified silicone rubber (SR) preform.

[0038] Step 2, Prepare the bottom of the sensor: 21) Align and adsorb the PI film onto the electrostatic film; 22) On the PI film fixed by the electrostatic sheet, print the bottom silver paste electrode according to the designed electrode structure. The line width is 0.20 mm, the printing height is 0.16 mm, the unit ink output is 1.00 ml / min, and the continuous ink output is 0.25 ml / min. Heat the printed silver paste electrode at 70℃ for 35 min to obtain the bottom electrode layer with completely cured silver on the bottom encapsulation layer of the PI film. 23) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; the line width is 0.20 mm, the printing height is 0.16 mm, the unit ink output is 1.10 ml / min, and the continuous ink output is 0.30 ml / min; place the printed silicone rubber pre-formulated liquid in an environment of 120℃ and heat for 100 min to cure, so as to obtain a fully cured bottom sealing layer on the PI film.

[0039] Step 3, Sensor Packaging: 31) The top and bottom of the prepared sensor were treated with oxygen plasma at 30% power for 40 seconds; 32) Align and place the pre-prepared structured dielectric layer 4 onto the bottom electrode layer 6; 33) Align the top and bottom of the sensor and seal them together. Peel off the electrostatic film on one side of the PI film to obtain the final sensor.

[0040] The structured dielectric layer is prepared according to the following method: a. Preparation of dielectric layer silicone rubber / carbon nanotube preform: The modified silicone rubber prepreg and carbon nanotubes were mixed at a mass ratio of 90:2 and magnetically stirred for 24 hours to obtain the dielectric layer silicone rubber / carbon nanotube prepreg. b. Fabrication of structured dielectric layers using a molding method The "positive mold" of the structure is prepared by 3D printing technology, and then cast with polydimethylsiloxane (PDMS). After heating and curing, the mold is demolded to obtain the "negative mold" of the structure. The dielectric layer pre-formed liquid is poured onto the "negative mold", heated and cured, and then demolded to obtain the structured dielectric layer. The dielectric layer units of the required size are then cut by laser cutting.

[0041] The obtained flexible capacitive barometric pressure sensor was calibrated. The flexible barometric pressure sensor in this embodiment has a wide range of -100kPa to +95kPa and can work stably in a temperature range of -70℃ to +130℃.

[0042] Example 3 Step 1, Prepare the top of the sensor: 11) Align and adsorb the PI film onto the electrostatic film; 12) On the PI film fixed by the electrostatic sheet, print the top silver paste electrode according to the designed electrode structure. The line width is 0.20 mm, the printing height is 0.16 mm, the unit ink output is 1.00 ml / min, and the continuous ink output is 0.20 ml / min. Heat the printed silver paste electrode at 60℃ for 40 min to obtain a top electrode layer with completely cured silver on the PI film encapsulation layer; 13) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; place the printed silicone rubber pre-formulated liquid in an environment of 120℃ and heat for 100 min to cure, so as to obtain a fully cured top sealing layer on the PI film.

[0043] The modified silicone rubber preform is prepared according to the following method: PDMS, cyclohexane curing agent, propylsilane, hydrogen-containing silicone oil or diisopropylbenzene peroxide, and vinylmethylsiloxane-dimethylsiloxane copolymer VMQ were mixed at a mass ratio of 95:10:5 and magnetically stirred for 24 hours to obtain modified silicone rubber (SR) preform.

[0044] Step 2, Prepare the bottom of the sensor: 21) Align and adsorb the PI film onto the electrostatic film; 22) On the PI film fixed by the electrostatic sheet, print the bottom silver paste electrode according to the designed electrode structure. The line width is 0.21 mm, the printing height is 0.16 mm, the unit ink output is 1.00 ml / min, and the continuous ink output is 0.20 ml / min. Heat the printed silver paste electrode at 60℃ for 40 min to obtain the bottom electrode layer with completely cured silver on the bottom encapsulation layer of the PI film. 23) Print the prepared modified silicone rubber pre-formulated liquid on the electrode layer according to the designed sealing layer structure; the line width is 0.20 mm, the printing height is 0.16 mm, the unit ink output is 1.10 ml / min, and the continuous ink output is 0.20 ml / min; place the printed silicone rubber pre-formulated liquid in an environment of 100℃ and heat for 120 min to cure, so as to obtain a fully cured bottom sealing layer on the PI film.

[0045] Step 3, Sensor Packaging: 31) The top and bottom of the prepared sensor were treated with oxygen plasma at a power of 35% for a duration of 35 seconds. 32) Align and place the pre-prepared structured dielectric layer onto the bottom electrode layer; 33) Align the top and bottom of the sensor and seal them together. Peel off the electrostatic film on one side of the PI film to obtain the final sensor.

[0046] The structured dielectric layer is prepared according to the following method: a. Preparation of dielectric layer silicone rubber / carbon nanotube preform: The modified silicone rubber prepreg and carbon nanotubes were mixed at a mass ratio of 100:4.5 and magnetically stirred for 24-48 hours to obtain the dielectric layer silicone rubber / carbon nanotube prepreg. b. Fabrication of structured dielectric layers using a molding method The "positive mold" of the structure is prepared by 3D printing technology, and then cast with polydimethylsiloxane (PDMS). After heating and curing, the mold is demolded to obtain the "negative mold" of the structure. The dielectric layer pre-formed liquid is poured onto the "negative mold", heated and cured, and then demolded to obtain the structured dielectric layer. The dielectric layer units of the required size are then cut by laser cutting.

[0047] The obtained flexible capacitive barometric pressure sensor was calibrated. The flexible barometric pressure sensor in this embodiment has a wide range of 100 kPa to +100 kPa and can work stably in a temperature range of -70℃ to +140℃.

[0048] refer to Figure 5The schematic diagram shown illustrates the design principle of the modified silicone rubber of this invention, demonstrating the role of the vinylmethylsiloxane-dimethylsiloxane copolymer (VMQ) in adjusting the segment distance of PDMS. PDMS component 10 is a polydimethylsiloxane with vinyl groups at the ends. In this embodiment, the elastic curing agent 11 is a hydrogen-containing silicone oil, and VMQ12 is the vinylmethylsiloxane-dimethylsiloxane copolymer. PDMS10, elastic curing agent 11, and VMQ12 are formulated. During heat curing, one end of the elastic curing agent 11 polymerizes with the vinyl groups at the ends of PDMS10, and the other end polymerizes with the vinyl groups on the side chains of VMQ12. In the polymer chain formed after curing, PDMS13 is connected to VMQ15 through the elastic curing agent 14. Therefore, the distance between the molecular chains of PDMS segment 13 and PDMS segment 16 can be adjusted by the distance between the vinyl groups on VMQ15.

[0049] refer to Figure 6 As shown, the stress curves of the unmodified and modified silicone rubbers of this invention under 30% strain cyclic loading at -70°C are presented. Applying 300 cycles of 30% strain cyclic loading at -70°C shows that the modified silicone rubber exhibits better elastic stability at low temperatures. From the above examples and... Figure 7 As can be seen, the flexible capacitive barometric pressure sensor of the present invention has a wide range of 100 kPa to +100 kPa and a low detection limit of 10 Pa.

[0050] refer to Figure 8 As shown, the flexible patch without modified silicone rubber and dielectric materials exhibits unstable signal during operation in a low-temperature environment of -70℃.

[0051] refer to Figure 9 As shown, the flexible sensing patch for wide-temperature-range air pressure monitoring of the present invention can operate stably in low-temperature environments of -70°C, normal-temperature environments of +20°C, and high-temperature environments of +140°C after the introduction of modified silicone rubber and dielectric materials.

[0052] refer to Figure 10 As shown, the prepared flexible patch can be perfectly attached to the surface of the wing model. Wind tunnel testing was conducted by installing the wing model inside a wind tunnel. The test results show that the surface wind pressure measured using the flexible patch is basically consistent with the surface wind pressure measured using a bit tube. Figure 11 .

[0053] The flexible patch sensor for wide-temperature-range air pressure monitoring provided by this invention operates by utilizing the deformation of the electrode plate caused by changes in internal and external pressure differences, which in turn alters the capacitance signal. By introducing a sealed cavity, a wide-range air pressure sensing capability from -100 kPa to +100 kPa is achieved. Simultaneously, modified silicone rubber is prepared by introducing VMQ into PDMS to adjust the distance between molecular chains, and then incorporating carbon nanotubes to create dielectric units. The introduction of modified silicone rubber and dielectric materials ensures stable operation of the device within a wide temperature range from -70°C to +140°C. This invention, through its attachable design, allows the sensing patch to conformally and stably adhere to the curved surface of an aircraft wing, providing a new method for real-time wind pressure monitoring on aircraft surfaces. Furthermore, this technology has the potential to be extended to monitoring air pressure on complex curved surfaces such as wind turbine blades and leaking pipes.

[0054] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A method for preparing a flexible patch sensor for wide temperature range air pressure monitoring, characterized in that, Includes the following steps: Step 1, Prepare the top of the sensor: a. Print the top electrode layer: Align the polyimide (PI) film with the electrostatic sheet film and adsorb it onto the electrostatic sheet film; A top silver paste electrode was printed on a polyimide (PI) film according to the electrode structure. The printed silver paste electrode is heated and cured to obtain a fully cured top electrode layer on the PI film; b. Print the top sealing layer: Modified silicone rubber preform was printed onto the electrode layer on the PI film according to the sealing layer structure. The printed modified silicone rubber SR pre-formed liquid was heated and cured to obtain a fully cured modified silicone rubber top sealing layer on the PI film; Step 2, Prepare the bottom of the sensor: a. Applying the bottom electrode layer: Align the polyimide (PI) film with the electrostatic sheet film and adsorb it onto the electrostatic sheet film; Print the bottom silver paste electrode on the polyimide (PI) film according to the electrode structure; The printed silver paste electrode is heated and cured to obtain a fully cured bottom electrode layer on the PI film; b. Print the bottom sealing layer: Modified silicone rubber SR preform was printed on the electrode layer of the PI film according to the sealing layer structure. The printed modified silicone rubber SR pre-formed liquid is heated and cured to obtain a fully cured modified silicone rubber bottom sealing layer on the PI film. Step 3, Sensor Packaging: The top and bottom of the prepared sensor were treated with oxygen plasma. Align the dielectric layer and place it on the bottom electrode layer; Align the top and bottom of the sensor for encapsulation, and peel off the electrostatic film on one side of the PI film to obtain a flexible patch sensor.

2. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 1, characterized in that, The modified silicone rubber preform was prepared according to the following method: The polydimethylsiloxane (PDMS), elastomer curing agent, and vinylmethylsiloxane-dimethylsiloxane copolymer (VMQ) were mixed and stirred in a mass ratio of (90~100):(8~10):(5~20).

3. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 2, characterized in that, The elastomer curing agent includes platinum hydrochloride, silane, hydrogen-containing silicone oil, or dicumyl peroxide.

4. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 1, characterized in that, The dielectric layer is prepared according to the following method: a. Mix and stir the modified silicone rubber prepreg with carbon nanotubes at a mass ratio of (90~100):(1~7.5) to obtain dielectric layer silicone rubber / carbon nanotube prepreg. b. A positive mold is prepared by 3D printing, which is then cast with polydimethylsiloxane (PDMS), heated and cured, and then demolded to obtain a negative mold. A pre-formulated dielectric layer of silicone rubber / carbon nanotubes is then cast onto the negative mold, heated and cured, and then demolded to obtain a structured dielectric layer.

5. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 4, characterized in that, The structured dielectric layer is laser-cut into a circle with a diameter smaller than that of the top electrode layer, top sealing layer, bottom sealing layer, and bottom electrode layer.

6. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 1, characterized in that, In steps 1 and 2, silver electrodes are printed with a line width of 0.20~0.21mm, a printing height of 0.15~0.16mm, a unit ink output of 1.00~1.10ml / min, and a continuous ink output of 0.20~0.30ml / min. Heat the printed silver paste electrode at 60-80℃ for 30-40 minutes.

7. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 1, characterized in that, Print modified silicone rubber preform liquid with a line width of 0.20~0.21mm, a printing height of 0.15~0.16mm, a unit ink output of 1.00~1.10ml / min, and a continuous ink output of 0.20~0.30ml / min; After printing the modified silicone rubber preform, heat it at 100~120℃ for 100~120 minutes to cure.

8. The method for fabricating a flexible patch sensor for wide-temperature-range air pressure monitoring according to claim 1, characterized in that, The oxygen plasma treatment power is 30-40%, and the duration is 30-40 seconds.

9. A flexible patch sensor for wide-temperature-range pressure monitoring, prepared by the method according to any one of claims 1-8, characterized in that, It includes, from top to bottom, a top encapsulation layer, a top electrode layer, a top sealing layer, a dielectric layer, a bottom sealing layer, a bottom electrode layer, and a bottom encapsulation layer; The top encapsulation layer is bonded to the top electrode layer and the top sealing layer, and the other side of the top electrode layer is bonded to the top sealing layer; the bottom encapsulation layer is bonded to the bottom electrode layer and the bottom sealing layer, and the other side of the bottom electrode layer is bonded to the bottom sealing layer. The top sealing layer is bonded to the bottom sealing layer on the other side by plasma treatment; the dielectric layer is located within the sealed cavity formed by the top electrode layer, the top sealing layer, the bottom sealing layer, and the bottom electrode layer.

10. The application of a flexible patch sensor for wide-temperature-range air pressure monitoring as described in claim 9 in real-time wind pressure monitoring on the surface of aerospace vehicles.

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