Manufacturing method of high-sensitivity and high-anti-interference flexible sensor used in space extreme environment

Abstract

The invention discloses a manufacturing method of a high-sensitivity and high-anti-interference flexible sensor used in a space extreme environment, and belongs to the technical field of flexible electronic device preparation. The method comprises the following steps: preparing a first conductive solution with high conductivity and radiation resistance and a second conductive solution with high flexibility and protectiveness; the conductive yarn with a composite sensitive structure is constructed in a two-step dipping and hot air drying mode; and an electrode is further led out, and a flexible sensing unit is constructed. The sensor has the capability of adapting to special environments such as space extreme temperature difference, strong irradiation, electromagnetic interference and the like, and can be applied to the fields of spacecraft state monitoring, space suit intelligent sensing systems and the like.

Description

Technical Field

[0001] This invention belongs to the field of flexible electronic devices, specifically relating to a method for fabricating a flexible sensor suitable for extreme space environments, and particularly to a highly sensitive and highly interference-resistant flexible sensor and its fabrication method that can operate stably under complex external conditions such as high temperature, low temperature, radiation, and electromagnetic interference. Background Technology

[0002] With the development of aerospace technology, the demand for intelligent sensing technology in spacecraft, spacesuits, and deep space exploration equipment is constantly increasing. In manned space missions, real-time monitoring of astronauts' movements and physiological states, as well as parameters such as deformation and pressure of key spacecraft components, is of great significance for improving mission safety and scientific value.

[0003] However, most flexible sensors are currently used in ground-based wearable devices operating at normal temperature and pressure, and they have the following drawbacks in the extreme environment of space: Flexible materials have unstable properties between -100℃ and +120℃, making them prone to breakage or failure. The material is susceptible to cosmic rays and strong ultraviolet radiation, which can accelerate aging. The electromagnetic interference intensity is high, and the sensing signal is easily shielded or distorted. There is a lack of composite conductive systems designed for yarn-level structures, resulting in poor sensitivity and linearity. Therefore, there is an urgent need to develop a flexible sensor that is highly stable, has strong anti-interference capabilities, and can adapt to the extreme environmental conditions of space. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating a highly sensitive and interference-resistant flexible sensor for use in extreme space environments, addressing the problems of poor environmental adaptability, low sensitivity, and weak interference suppression capabilities in existing technologies. This invention employs nano-carbon materials with high conductivity and radiation protection capabilities as the first sensitive layer, while introducing a high-molecular conductive polymer and fluorinated materials as the second protective layer, constructing a double-layer composite conductive yarn structure. In the electrode connection portion, multi-layer shielded wires are bonded with conductive silver paste to improve electromagnetic compatibility performance. Finally, a flexible sensing array or structural unit is formed through weaving or other methods, enabling its integrated application in spacecraft, spacesuits, and other systems. Attached Figure Description

[0005] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1This is a flowchart illustrating the method for fabricating a highly sensitive and interference-resistant flexible sensor for use in extreme space environments provided by the present invention. Figure 2 This is a stress-strain diagram of the flexible yarn sensor provided by the present invention; Figure 3 This is a relative resistance change-strain diagram of the flexible yarn sensor provided by the present invention; Figure 4 This invention provides the repeatability of the flexible yarn sensor within a 50% strain range. Figure 5 This is an enlarged view of the sensor portion provided by the present invention. Detailed Implementation

[0006] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0007] In space missions, such as extravehicular maintenance on space stations and planetary surface exploration, conventional control and monitoring methods face numerous challenges due to the closed and isolated conditions astronauts are in. The space environment presents multiple adverse factors, including extreme temperature differences, high-energy particle radiation, and electromagnetic interference. Therefore, it is necessary to develop an intelligent sensing solution that can adapt to these special environments. This invention proposes a method for fabricating a highly sensitive and highly interference-resistant flexible sensor for use in the extreme environment of space, capable of long-term stable operation under conditions of -100℃ to +120℃, high electromagnetic interference, and radiation. Specifically, Figure 1 This is a flowchart illustrating the fabrication process of the flexible sensor provided by the present invention, including: Step 101: Prepare a first conductive solution with high conductivity and radiation resistance, and a second conductive solution with high flexibility and protection; Step 102: Immerse the yarn in the first conductive solution and then remove it. Dry it with hot air to obtain conductive yarn. Step 103: Immerse the conductive yarn in the second conductive solution and then remove it. After hot air drying, a conductive yarn with a protective coating is obtained. Step 104: Lead out electrodes from both ends of the conductive yarn with protective coating and construct a flexible sensing unit to obtain a flexible sensor; Step 105: Based on the aforementioned flexible sensor, knitting technology is used to knit a highly sensitive and interference-resistant flexible sensor for use in extreme space environments.

[0008] In step 101, carbon material is first uniformly dispersed in deionized water using a dispersant and then oscillated using an ultrasonic disperser for 30 minutes to maintain the mass fraction of the first conductive solution at 5-15%. Similarly, the second conductive solution is prepared to make its mass fraction greater than 3%. Preferably, the carbon material includes at least one of carbon nanotubes, graphene, carbon black, and graphite; Preferably, the material based on the conductive polymer includes at least one of poly(3,4-ethylenedioxythiophene): poly(sodium styrene sulfonate), polyaniline, and polypyrrole;

[0009] In step 102, the cleaned yarn is first immersed in a first conductive solution for 5-10 minutes, followed by drying in hot air at 80-100 degrees Celsius for 2 minutes, resulting in a uniform carbon material layer on the yarn surface. The yarn is a covered yarn with a diameter of 0.1mm-3mm, preferably composed of at least one of cotton, linen, wool, silk, polyester, spandex, nylon, and acrylic.

[0010] In step 103, the yarn with the carbon material layer from step 102 is immersed in the second conductive solution for 5 to 10 minutes, and then dried in hot air at 80 to 100 degrees Celsius for 3 minutes, so that a uniform polymer conductive film layer is formed on the surface of the carbon material layer.

[0011] In step 104, conductive silver paste is used to bond the two ends of the obtained conductive yarn to the shielded wire. The wire has a silver-clad copper structure, covered with a PI film and a metal braided layer. The wire diameter is 0.1~1mm, the bonding temperature is 120℃, and the bonding time is 3 minutes.

[0012] In step 105, the sensor was tested and found to maintain more than 95% signal stability during repeated thermal cycling from -100℃ to +120℃, with its anti-EMI interference capability improved by 3 times, and it has extremely strong environmental adaptability. The technical solution of the present invention will be further described below through Example 1 and comparative examples:

[0013] Example 1: Multi-walled carbon nanotubes (MWC nanotubes) were dispersed in deionized water using a dispersant and ultrasonically dispersed to obtain a 13% MWC MWC nanotube aqueous solution as the first conductive solution. A 5% MWPEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(sodium styrene sulfonate)) solution was used as the second conductive solution. Cleaned polyester-coated yarn was immersed in the first conductive solution, removed and dried after 10 minutes, and then dried in hot air at 90 degrees Celsius for 2 minutes to form a MWC nanotube layer on the yarn surface. Based on the above yarn, it was further immersed in the second conductive solution, and the same drying process was used to obtain a PEDOT:PSS-MWC nanotube-coated conductive yarn. The two ends of the conductive yarn were connected to silver-plated wires, and the connection was bonded with conductive silver paste to obtain a flexible yarn sensor. The flexible yarn sensor, 2.5 times the length of a finger, was selected and knitted using a "bow" structure with ordinary fabric needles to finally weave it into a sensor mesh that can fit the structure required for space applications.

[0014] Comparative Example 1: In the comparative example, the impregnation process only uses the first conductive solution and does not use the second conductive solution. The remaining steps follow steps 101, 102, 104, and 105 of the method for preparing a sensing glove based on a flexible yarn sensor. The difference between Comparative Example 1 and Example 1 is: The yarn surface has only a carbon material layer; R² is used to measure the linearity of the sensor. In actual testing, it was found that the sensor fabricated in Comparative Example 1 had low linearity, with an R² of 0.932, while the R² of Example 1 was as follows: Figure 3 The value shown is 0.998. This is because there are uneven gaps between the carbon material layers under strain, which reduces the stability and linearity under tension, making it unable to meet the requirements of stable sensing and detection.

[0015] Comparative Example 2: A method for fabricating a highly sensitive and interference-resistant flexible sensor for use in extreme space environments is provided. In the comparative example, the impregnation process uses only the second conductive solution and not the first conductive solution. The remaining steps follow steps 101, 103, 104, and 105 of the method for fabricating a sensing glove based on a flexible yarn sensor. The difference between Comparative Example 2 and Example 1 is: The yarn surface has only a PEDOT:PSS layer; GF is used to measure the sensitivity of a sensor. In actual testing, it was found that the sensor line fabricated in Comparative Example 2 had low sensitivity, with a GF of 2.66, while the GF of Example 1 was... Figure 3 The value shown is 6.16. This is because conductive polymers have excellent conductivity, and the polymer structure can build a stable conductive network under tension, which leads to improved linearity but reduced sensor sensitivity.

[0016] Comparative Example 3: In this comparative example, twisted polyester fibers were used for impregnation, without the use of polyester covering yarn. The remaining steps followed steps 101-105 of the method for preparing a highly sensitive and interference-resistant flexible sensor for use in extreme space environments. The difference between Comparative Example 3 and Example 1 is as follows: The one-dimensional flexible substrate used is different; In actual testing, it was found that the strain range of the sensor fabricated in Comparative Example 3 was only 0-50%, and the Young's modulus was 5 MPa, while that in Example 1... Figure 2 As shown, the strain range of the flexible yarn sensor is 0~200%, and the Young's modulus is 0.09MPa. The low modulus characteristic can improve the comfort of sensing and detection.

[0017] Figure 2 This invention provides a stress-strain diagram of a highly sensitive and interference-resistant flexible sensor for use in extreme space environments, with strain ranging from 0% to 200%. The sensor features low modulus and a wide strain detection range. Figure 3 This is a relative resistance change-strain diagram of the flexible yarn sensor provided by the present invention at 0~200%, and the sensor has the characteristics of high sensitivity and high linearity; Figure 4 This is a performance cycle diagram of the flexible yarn sensor provided by the present invention at 0~50% for 20,000 cycles, and the sensor has excellent stability performance.

[0018] Figure 5 This is an enlarged view of the highly sensitive and interference-resistant flexible sensor 1 for use in extreme space environments, showing the "bow" knitted structure of the sensor, including a flexible yarn sensor 4 and a regular fabric 5. The flexible yarn sensor is mixed with the regular fabric paper, which improves the structural stability, reduces the relative slippage between the sensor and its location, and improves the detection accuracy. At the same time, this structure can also improve the longitudinal sensitivity of the sensor to 200%.

Claims

1. A method for fabricating a highly sensitive and interference-resistant flexible sensor for use in extreme space environments, characterized in that, include: Using carbon nanotubes, graphene, or their composites as conductive media, and adding an appropriate amount of dispersant, the solution is dispersed in an ethanol-water mixed solvent and sonicated for 30 minutes to form a first conductive solution with high conductivity and strong radiation resistance. A second conductive solution with both flexibility and protective properties is formed by mixing poly(3,4-ethylenedioxythiophene):poly(sodium styrene sulfonate) (PEDOT:PSS) with fluorinated polymers (such as polytetrafluoroethylene PTFE) to construct the protective layer structure of the sensor. High-strength, heat-resistant fibers (such as aramid and liquid crystal polymer fibers) are selected to make yarn with a diameter of 0.1 mm. The yarn is then immersed in a first conductive solution and a second conductive solution for 10 minutes each. After each immersion, the yarn is dried with hot air at 90°C for 3 minutes to form a flexible yarn with a composite conductive layer. High-strength heat-resistant yarn is sequentially immersed in the first conductive solution and the second conductive solution, each time for 5 to 10 minutes, and then dried under 90°C hot air for 3 minutes to obtain composite conductive yarn. Electrodes are led out from both ends of the conductive yarn. The electrodes are made of multi-layer shielded wires and are bonded with conductive silver paste. Multiple conductive yarns are woven into flexible sensing units or arrays to form the final sensor.

2. The highly sensitive and interference-resistant flexible sensor for extreme space environments according to claim 1, characterized in that, In the process of preparing a first conductive solution based on carbon materials and a second conductive solution based on a polymeric conductive polymer; Preferably, the carbon material in the first conductive solution is at least one of carbon nanotubes, graphene, carbon black, or graphite, with a mass fraction of 5% to 15%. Preferably, the conductive polymer material in the second conductive solution is at least one of PEDOT:PSS, polyaniline, and polypyrrole, and 3-6% of fluorinated polymer components are incorporated to enhance radiation resistance and film quality.

3. The highly sensitive and interference-resistant flexible sensor for extreme space environments according to claim 1, characterized in that, The base fiber used in the conductive yarn is selected from aramid, liquid crystal polymer, polyester, spandex, nylon or mixtures thereof, and the fiber diameter is controlled within the range of 0.1mm to 3mm; The impregnation time is 5-10 minutes, the hot air drying temperature is 80-100 degrees Celsius, and the drying time is 2-3 minutes to ensure that the conductive layer is fully bonded to the fiber surface and the structure is stable.

4. The highly sensitive and highly interference-resistant flexible sensor for extreme space environments according to claim 1, characterized in that, Electrodes are led out using wires, including: A flexible yarn sensor is obtained by bonding the two ends of a conductive yarn with a protective coating and a wire together using conductive silver paste. The diameter of the conductor is 0.1mm to 1mm. Preferably, the conductor includes one of silver conductor, copper conductor and aluminum conductor.

5. The highly sensitive and interference-resistant flexible sensor for extreme space environments according to claim 1, characterized in that, Based on the aforementioned flexible yarn sensor, a flexible sensing unit is knitted using knitting technology, comprising: The construction method adopts a "bow" structure knitted layout, which evenly distributes conductive yarns in conventional fabrics, enabling the acquisition of multi-dimensional signals such as strain, bending, and pressure, while ensuring conformability and adaptability.

6. A highly sensitive and highly interference-resistant flexible sensor for use in extreme space environments, characterized in that: Includes a flexible yarn sensor, a data processing unit, and a receiving device actuator obtained using any of the highly sensitive and interference-resistant flexible sensors for extreme space environments as described in claims 1-5; The highly sensitive and interference-resistant flexible sensor for use in extreme space environments is connected to a data processing unit. The data processing unit includes data acquisition, data processing, and wireless transmission functions, and the wireless transmission function is connected to the receiver actuator.

7. The highly sensitive and highly interference-resistant flexible sensor for extreme space environments according to claim 6, characterized in that, The data acquisition unit collects strain or bending electrical signals from multiple flexible sensing nodes, converts the signals into voltage signals through a voltage divider and filter circuit, and then converts them into digital signals through an A / D conversion module.

8. The highly sensitive and highly interference-resistant flexible sensor for extreme space environments according to claim 6, characterized in that, The wireless transceiver unit is used to transmit control commands from the sensing device to the receiving device actuator. The wireless communication module automatically adjusts its frequency in different communication bands to avoid electromagnetic interference inside the spacecraft.

Images