Flexible integrated gas sensor and method of manufacture
By using a carbon-based substrate and a C/e-PTEF/C composite substrate encapsulation structure and electrospinning technology to prepare a gas-sensitive thin film in a flexible gas sensor, the problems of sensor failure and multi-gas detection under high temperature environment are solved, and stable detection of NOx, CO, CO2 and O2 is achieved, improving measurement accuracy and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2023-12-29
- Publication Date
- 2026-05-19
AI Technical Summary
Existing flexible gas sensors are prone to failure in high-temperature environments, making it difficult to simultaneously detect multiple toxic and harmful gases such as NOx, CO, CO2, and O2. Furthermore, the sensors are susceptible to the effects of smoke, moisture, and dust, resulting in poor measurement accuracy and stability.
An encapsulation structure using a bottom carbon-based substrate and a top carbon-based/expanded polytetrafluoroethylene/carbon-based (C/e-PTEF/C) composite substrate is used to prepare a gas-sensitive film by electrospinning technology. PVP/graphene, PVP/carbon nanotube/CuO@Pt, PVP/polyaniline, and PVP/polypyrrole@Ag are used as gas-sensitive materials, and oblique through-hole structures are prepared by laser processing to form a high-temperature resistant, waterproof and breathable encapsulation protection.
It effectively blocks smoke and dust pollution in high-temperature environments, isolates the effects of moisture and dust, ensures the measurement accuracy and performance stability of the sensor, and enables simultaneous detection of multiple gases.
Smart Images
Figure CN117805191B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of multi-component gas detection and flexible high-temperature resistance, specifically to a flexible integrated gas sensor for NOx, CO, CO2, and O2, and a method for its fabrication. Background Technology
[0002] Gas sensors are core devices for acquiring information on the composition and concentration of gases in the environment. They span numerous fundamental and applied disciplines, including microelectromechanical systems (MEMS), functional materials, nanotechnology, organic polymers, and optoelectronic components, demonstrating enormous application potential and value in fields such as industrial production, environmental monitoring, fire rescue, hazardous material disposal, and artificial intelligence. With the rapid development of the Internet of Things (IoT) and electronic technologies, more and more electronic devices are evolving towards miniaturization, low power consumption, intelligence, and flexibility. Gas sensors are also gradually shifting from traditional rigid structures on inorganic substrates such as quartz, glass, and alumina ceramic tubes to being manufactured on flexible substrates such as polymers, textiles, and paper substrates. This overcomes the shortcomings of traditional rigid structures, such as poor ductility, large size, and low flexibility, making them more adaptable to complex monitoring and precise operational requirements.
[0003] However, currently reported flexible integrated gas sensors generally only target two different types of gases, and flexible sensing methods focusing on three or even four different gas components are rarely reported. In situations such as explosions and fires, which easily generate multiple irritating (e.g., NOx) and asphyxiating (e.g., CO) gases, simultaneous detection of toxic and harmful gases as well as gases closely related to human respiration (e.g., CO2, O2) in the on-site environment would provide rescue personnel with comprehensive high-temperature on-site gas environmental parameters, thus providing effective data support and important basis for quickly formulating rescue plans and deploying on-site rescue measures. However, due to the low temperature resistance (below 300℃) and easy performance failure of flexible materials at high temperatures, flexible multi-parameter sensing methods for complex gas mixtures in high-temperature and harsh environments such as explosions and fires are still lacking. Summary of the Invention
[0004] The purpose of this invention is to provide a flexible integrated gas sensor and its fabrication method to overcome the shortcomings of the prior art.
[0005] A flexible integrated gas sensor includes a bottom carbon-based substrate, an interdigitated electrode substrate attached to the upper surface of the bottom carbon-based substrate, a sensor array unit structure arrayed on the bottom carbon-based substrate above the interdigitated electrode substrate, and a top carbon-based / expanded polytetrafluoroethylene / carbon-based composite substrate disposed on the upper end of the sensor array unit structure.
[0006] Preferably, the sensor array unit structure on the underlying carbon substrate is arranged in a linear array or a ring array.
[0007] Preferably, the top C / e-PTEF / C composite substrate includes an upper carbon substrate and a lower carbon substrate, with an e-PTEF thin film layer disposed between the upper carbon substrate and the lower carbon substrate.
[0008] Preferably, the e-PTEF film layer is a waterproof and breathable membrane.
[0009] Preferably, multiple through holes are provided on both the upper and lower carbon substrates, and the through holes on the upper and lower carbon substrates are inclined.
[0010] Preferably, the angle between the through holes on the upper and lower carbon substrates and the e-PTEF film layer is 30°-60°.
[0011] Preferably, the sensor array unit structure and the interdigitated electrode substrate are both bonded to the underlying carbon substrate using high-temperature sealant.
[0012] Preferably, the sensor array unit structure specifically adopts a sensor gas-sensitive thin film. Different sensor array unit structures arrayed on the underlying carbon substrate include PVP / graphene, PVP / carbon nanotube / CuO@Pt, PVP / polyaniline and PVP / polypyrrole@Ag, which are used as gas-sensitive materials for sensing NOx, CO, CO2 and O2 gases, respectively.
[0013] A method for fabricating a flexible integrated gas sensor includes the following steps:
[0014] The bottom carbon substrate is cleaned, and the interdigitated electrode substrate is bonded to the bottom carbon substrate with high-temperature sealant.
[0015] A gas-sensitive thin film layer was generated on a carbon-based substrate using electrospinning technology.
[0016] Finally, a flexible integrated gas sensor was obtained by encapsulating it using a carbon-based / expanded polytetrafluoroethylene / carbon-based composite structure.
[0017] Preferably, the specific parameters for generating a gas-sensitive thin film layer on a carbon-based substrate using electrospinning technology are: positive and negative voltages of +12V and -5V respectively, spinning distance of 12mm, nozzle orifice diameter of 0.2mm, take-up roller speed of 500r / min, and spinning time of 40min.
[0018] Compared with the prior art, the present invention has the following beneficial technical effects:
[0019] This invention provides a flexible integrated gas sensor, comprising a bottom carbon-based substrate, an interdigitated electrode substrate attached to the upper surface of the bottom carbon-based substrate, a sensor array unit structure arrayed on the bottom carbon-based substrate above the interdigitated electrode substrate, and a top carbon-based / expanded polytetrafluoroethylene / carbon-based (C / e-PTEF / C) composite substrate disposed on the upper end of the sensor array unit structure. This application uses the bottom carbon-based substrate and the top carbon-based / expanded polytetrafluoroethylene / carbon-based (C / e-PTEF / C) composite substrate as the bottom and top layers, respectively, to form a high-temperature resistant encapsulation and protection structure. This invention can not only effectively block the contamination of the gas-sensitive unit by smoke and dust generated by explosions, fires, etc., but also effectively isolate the influence of moisture and dust in the air on the gas-sensitive unit under normal temperature conditions, which is beneficial to ensuring the measurement accuracy and performance stability of the sensor.
[0020] Preferably, the upper and lower carbon substrates are fabricated with oblique through-hole structures using laser processing. This not only ensures the normal flow of different gas components in the air, but also effectively avoids the direct impact of airflow on the gas-sensitive unit of the sensor. The tilt angle of the laser processing ranges from 30° to 60°. The intermediate e-PTEF film is a waterproof and breathable membrane with a fibrous polymer microporous structure and good mechanical properties. It can effectively block the contamination of the gas-sensitive unit by smoke and dust generated by explosions and fires, and at room temperature, it can also effectively isolate the gas-sensitive unit from the influence of moisture and dust in the air, which helps to ensure the measurement accuracy and performance stability of the sensor.
[0021] Preferably, the electrospinning technology used in this application has the advantages of being simple, efficient and capable of continuously preparing nanofibers and micro / nanoparticles. In particular, it can achieve one-time spinning of films after doping with various nanomaterials, which has attracted widespread attention in the field of sensors. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the flexible integrated gas sensor structure in an embodiment of the present invention.
[0023] Figure 2 This is a schematic diagram of a sensor array unit structure arranged in a linear array according to an embodiment of the present invention.
[0024] Figure 3 This is a schematic diagram of a sensor array unit structure arranged in a ring array in an embodiment of the present invention.
[0025] In the figure, 1. Bottom carbon substrate; 2. Interdigitated electrode substrate; 3. Sensor array unit structure; 4. Top carbon / expanded polytetrafluoroethylene / carbon composite substrate; 5. High-temperature sealant; 6. Upper carbon base layer; 7. Lower carbon base layer; 8. e-PTEF thin film layer. Detailed Implementation
[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0028] like Figure 1 As shown, this invention provides a flexible integrated gas sensor, including a bottom carbon substrate 1, an interdigitated electrode substrate 2 attached to the upper surface of the bottom carbon substrate 1, a sensor array unit structure 3 arrayed on the bottom carbon substrate 1 at the upper end of the interdigitated electrode substrate 2, and a top carbon-based / expanded polytetrafluoroethylene / carbon-based (C / e-PTEF / C) composite substrate 4 disposed at the upper end of the sensor array unit structure 3. This application uses the bottom carbon substrate 1 and the top carbon-based / expanded polytetrafluoroethylene / carbon-based (C / e-PTEF / C) composite substrate as the bottom and top layers, respectively, to form a high-temperature resistant encapsulation and protection structure. This invention can not only effectively block the contamination of the gas-sensitive unit by smoke and dust generated by explosions, fires, etc., but also effectively isolate the influence of moisture and dust in the air on the gas-sensitive unit under normal temperature conditions, which is beneficial to ensuring the measurement accuracy and performance stability of the sensor.
[0029] Specifically, the sensor array unit structure on the underlying carbon substrate 1 is arranged in a linear array or a ring array, such as... Figure 2 As shown, the sensor array unit structure on the bottom carbon substrate 1 is a linear array; as Figure 3 As shown, the sensor array unit structure on the bottom carbon substrate 1 is arranged in a ring array. This application provides four sensor array unit structures arranged in a ring array, and the included angle between two adjacent sensor array unit structures arranged in a ring array is 90°.
[0030] The top C / e-PTEF / C composite substrate includes an upper carbon base layer 6 and a lower carbon base layer 7. An e-PTEF thin film layer 8 is disposed between the upper carbon base layer 6 and the lower carbon base layer 7. The e-PTEF thin film layer is a waterproof and breathable membrane.
[0031] Multiple through holes are provided on both the upper carbon substrate 6 and the lower carbon substrate 7. The through holes on the upper carbon substrate 6 and the lower carbon substrate 7 are inclined, and the angle between the through holes on the upper carbon substrate 6 and the lower carbon substrate 7 and the e-PTEF thin film layer 8 is 30°-60°.
[0032] Both the sensor array unit structure 3 and the interdigitated electrode substrate 2 are bonded to the underlying carbon substrate 1 by high-temperature sealant 5.
[0033] The sensor array unit structure 3 specifically adopts a sensor gas-sensitive thin film. Different sensor array unit structures 3 arrayed on the bottom carbon substrate 1 include PVP / graphene, PVP / carbon nanotube / CuO@Pt, PVP / polyaniline and PVP / polypyrrole@Ag, which are used as gas-sensitive materials for sensing NOx, CO, CO2 and O2 gases, respectively.
[0034] In this embodiment, the sensor gas-sensitive film is prepared by electrospinning technology. The electrospinning process parameters are: positive and negative voltages of +12V and -5V respectively, spinning distance of 12mm, nozzle needle diameter of 0.2mm, take-up roller speed of 500r / min, and spinning time of 40min.
[0035] The gas-sensitive unit is the core sensing component of the integrated gas sensor, comprising two parts: the interdigitated electrode substrate 2 and the sensor array unit structure 3. The interdigitated electrode substrate 2 is made of Cu / Au material with good conductivity and flexibility, and is formed on a carbon-based substrate using micromachining technology. The sensor array unit structure 3 (gas-sensitive thin film) is formed on the interdigitated electrode structure using an electrospinning process. A schematic diagram of the flexible integrated gas sensor is shown below. Figure 1 As shown, in order to meet the installation requirements of complex structural components with different shapes, the array structure adopts various forms such as linear array or ring array. On the basis of miniaturizing the array, the spatial layout is designed to maximize the fit of the sensor to the surface of the mounting component.
[0036] In this application, PVP / graphene, PVP / carbon nanotube / CuO@Pt, PVP / polyaniline, and PVP / polypyrrole@Ag are used as gas-sensitive materials for sensing NOx, CO, CO2, and O2 gases, respectively.
[0037] A gas-sensitive thin film for the sensor was prepared using electrospinning technology. When preparing the gas-sensitive thin film for the sensor using electrospinning technology, a mixed solution for electrospinning is required. In preparing the mixed solution for electrospinning, 10 mg of graphene, 10 mg of carbon nanotubes / CuO@Pt, 15 mg of polyaniline and 10 mg of polypyrrole@Ag composite nanomaterials were added to 10 g of PVP and stirred with a magnetic stirrer for about 4 hours until the mixed solution was uniformly distributed.
[0038] The preparation process of carbon nanotube / CuO@Pt composite material is as follows: First, carbon nanotubes and CuO nanopowder are mixed and added to an appropriate amount of anhydrous ethanol. After magnetic stirring and ultrasonic treatment, Pt nanopowder is added. The magnetic stirring and ultrasonic treatment are repeated, followed by drying in a drying oven. Finally, it is ground into powder to obtain carbon nanotube / CuO@Pt composite nanopowder. The mass ratio of carbon nanotubes, CuO, and Pt nanopowder is 1:10:5. The preparation process of polypyrrole@Ag composite material is similar to that of carbon nanotube / CuO@Pt composite material, in which the mass ratio of polypyrrole to Ag is 5:1.
[0039] This application employs micromachining technology to fabricate the interdigitated electrodes of a flexible integrated gas sensor. A carbon-based thin film with good temperature resistance is used as the flexible substrate. Since the cleanliness of the substrate significantly affects the fabrication of the interdigitated electrode structure, the substrate surface is first ultrasonically cleaned sequentially with acetone solution, anhydrous ethanol solution, and deionized water to remove dust particles and other impurities. Then, the Cu / Au interdigitated electrode substrate is fabricated sequentially through a process of "cleaning-spin-coating-photolithography-sputtering-stripping". After fabricating a single interdigitated electrode structure, the sensor array unit structure 3 is fabricated using an integration process. This application utilizes electrospinning technology, which offers advantages such as simplicity, efficiency, and the ability to continuously fabricate nanofibers and micro / nanoparticles. In particular, it enables the one-time spinning of films after doping with various nanomaterials, attracting widespread attention in the sensor field.
[0040] In this application, the gas-sensitive thin film layer is prepared using electrospinning technology. Under the influence of an electric field, solutions of different gas-sensitive materials are injected sequentially or simultaneously into a roller receiver in fibrous form using a syringe. By adjusting the processing parameters such as electric field voltage, solution concentration and viscosity, spinning distance, spinneret orifice diameter and spacing, and take-up roller rotation speed, the gas-sensitive film of the sensor is finally prepared. The electrospinning process parameters are: positive and negative voltages of +12V and -5V, respectively; spinning distance of 12mm; spinneret orifice diameter of 0.2mm; take-up roller rotation speed of 500r / min; and spinning time of 40min.
[0041] High temperatures, hot air currents, and smoke generated by explosions and fires significantly impact the detection capabilities of gas sensors, severely interfering with their measurement accuracy and recognition precision, and even causing detection failure. To achieve stable high-temperature operation of flexible gas sensors, this application employs screen printing technology to prepare a heat-resistant carbon-based substrate, on which interdigitated electrode structures and a gas-sensitive thin film are sequentially formed. The top-layer encapsulation utilizes a carbon-based / expanded polytetrafluoroethylene / carbon-based (C / e-PTEF / C) three-layer composite structure, effectively reducing damage and interference from high-temperature environments to the flexible sensor.
[0042] The upper and lower carbon substrates are fabricated with oblique through-hole structures using laser processing. This not only ensures the normal flow of different gas components in the air, but also effectively avoids the direct impact of airflow on the gas-sensitive unit of the sensor. The tilt angle of the laser processing ranges from 30° to 60°. The intermediate e-PTEF film is a waterproof and breathable membrane with a fibrous polymer microporous structure and excellent mechanical properties. It can effectively block smoke and dust generated by explosions and fires from contaminating the gas-sensitive unit of the sensor. Under normal temperature conditions, it can also effectively isolate the gas-sensitive unit from the influence of moisture and dust in the air, which helps to ensure the measurement accuracy and performance stability of the sensor.
Claims
1. A flexible integrated gas sensor, characterized in that, It includes a bottom carbon substrate (1), an interdigitated electrode substrate (2) is attached to the upper surface of the bottom carbon substrate (1), a sensor array unit structure (3) is arrayed on the bottom carbon substrate (1) at the upper end of the interdigitated electrode substrate (2), and a top carbon-based / expanded polytetrafluoroethylene / carbon-based composite substrate (4) is disposed at the upper end of the sensor array unit structure (3).
2. The flexible integrated gas sensor according to claim 1, characterized in that, The sensor array unit structure on the bottom carbon substrate (1) is arranged in a linear array or a ring array.
3. The flexible integrated gas sensor according to claim 1, characterized in that, The top C / e-PTEF / C composite substrate includes an upper carbon substrate (6) and a lower carbon substrate (7), with an e-PTEF thin film layer (8) disposed between the upper carbon substrate (6) and the lower carbon substrate (7).
4. A flexible integrated gas sensor according to claim 3, characterized in that, The e-PTEF membrane layer is a waterproof and breathable membrane.
5. A flexible integrated gas sensor according to claim 1, characterized in that, Multiple through holes are provided on both the upper carbon base layer (6) and the lower carbon base layer (7), and the through holes on the upper carbon base layer (6) and the lower carbon base layer (7) are inclined.
6. A flexible integrated gas sensor according to claim 5, characterized in that, The angle between the through holes on the upper carbon substrate (6) and the lower carbon substrate (7) and the e-PTEF thin film layer (8) is 30°-60°.
7. A flexible integrated gas sensor according to claim 1, characterized in that, The sensor array unit structure (3) and the interdigitated electrode substrate (2) are both bonded to the underlying carbon substrate (1) with high-temperature sealant (5).
8. A flexible integrated gas sensor according to claim 1, characterized in that, The sensor array unit structure (3) specifically adopts a sensor gas-sensitive thin film. Different sensor array unit structures (3) arrayed on the bottom carbon substrate (1) include PVP / graphene, PVP / carbon nanotube / CuO@Pt, PVP / polyaniline and PVP / polypyrrole@Ag, which are respectively used as gas-sensitive materials for sensing NOx, CO, CO2 and O2 gases.
9. A method for fabricating a flexible integrated gas sensor, characterized in that, Includes the following steps: The bottom carbon substrate is cleaned, and the interdigitated electrode substrate is bonded to the bottom carbon substrate with high-temperature sealant. A gas-sensitive thin film layer was generated on a carbon-based substrate using electrospinning technology. Finally, a flexible integrated gas sensor was obtained by encapsulating it using a carbon-based / expanded polytetrafluoroethylene / carbon-based composite structure.
10. The method for fabricating a flexible integrated gas sensor according to claim 9, characterized in that, The specific parameters for generating a gas-sensitive thin film layer on a carbon-based substrate using electrospinning technology are as follows: positive and negative voltages of +12V and -5V, respectively; spinning distance of 12mm; nozzle orifice diameter of 0.2mm; take-up roller speed of 500r / min; and spinning time of 40min.