Flexible sensor and preparation method thereof

Abstract

The invention provides a flexible sensor and a preparation method thereof. The flexible sensor comprises a high-temperature-resistant fabric 101 and a sensing carbon film layer 102, wherein the high-temperature-resistant fabric 101 is a base material of the flexible sensor; the sensing carbon film layer 102 is provided with a pattern corresponding to the sensing function of the flexible sensor, and the sensing carbon film layer 102 covers the high-temperature-resistant fabric 101. The flexible sensor is simple in structure, sensing of different physical quantities can be achieved by setting the pattern of the sensing carbon film layer, and the flexible sensor has the advantages of being simple and convenient in technology and simple in preparation process.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a flexible sensor and its fabrication method. Background Technology

[0002] With the advancement of industrialization, robots have gradually replaced human workers in labor-intensive and hazardous environments, such as assembly robots and handling robots in the automotive industry. When robots operate, they need to accurately perceive environmental information to achieve efficient and stable automated operation. Flexible sensors play a crucial role in this process. However, current flexible sensors still have some problems that urgently need to be solved, such as poor high-temperature resistance, leading to decreased or even failed sensing performance in high-temperature environments, causing robots to be unable to accurately perceive their surroundings, affecting work efficiency and safety; poor flexibility, making them unsuitable for sensing complex shapes; and high density, making it impossible to meet lightweight requirements.

[0003] Researchers have developed various substrate materials suitable for flexible sensors, enabling the fabrication of high-temperature resistant flexible sensors with different functions. Existing technologies utilize substrate materials including metals, liquid metals, polymers, carbon-based materials, and multi-component composite materials. However, each of these existing solutions has significant drawbacks, limiting their widespread adoption and use in practical applications.

[0004] While metal-based flexible sensors perform reasonably well in some mechanical aspects, their high density results in a relatively heavy overall weight, limiting their application in scenarios with stringent lightweight requirements. More importantly, the poor flexibility of the metal substrate makes it difficult to meet the demands of use under complex deformation conditions, and insufficient deformation can easily affect the sensor's performance and lifespan.

[0005] While liquid metal-based flexible sensors possess strong conformal capabilities, they also suffer from high density. Furthermore, the high cost of liquid metals makes large-scale production and application of flexible sensors using this substrate material prohibitively expensive, hindering widespread commercialization and significantly limiting their market competitiveness and application scope.

[0006] Polymer-based flexible sensors can meet the requirements for use under deformation conditions relatively well. However, their high-temperature resistance is poor. When exposed to high-temperature environments, the polymer substrate is prone to deformation and aging, leading to a sharp decline in sensor performance. This limits polymer-based flexible sensors mainly to applications at room temperature or lower temperatures, rendering them ineffective for monitoring in high-temperature environments and greatly restricting their application areas.

[0007] Carbon-based materials, with their excellent electrical conductivity, superior chemical stability, ease of functionalization, abundant resource sources, and diverse structural characteristics, have become a hot research topic in flexible sensor substrate materials. Based on different fabrication methods and packaging processes, carbon-based flexible sensors can be divided into two types: filled and adsorbed. Filled sensors involve adding a specific proportion of carbon material as a conductive filler to a polymer matrix to form a permeable conductive network; adsorbed sensors utilize techniques such as dip coating, spraying, thermochemical vapor deposition (CVD), or plasma-assisted chemical vapor deposition to achieve uniform adsorption of carbon material onto the surface of a polymer substrate or textile.

[0008] Existing carbon-based flexible sensors have the following shortcomings: Firstly, their structures mostly employ a sandwich structure, making the fabrication process cumbersome and complex, which is not conducive to large-scale production and practical applications. Secondly, current carbon-based flexible sensors have relatively limited functions, making it difficult to achieve multi-functional integration or array-based integration, thus failing to meet the increasingly complex and diverse practical application requirements. Furthermore, the high-temperature resistance of carbon-based flexible sensors still needs improvement, especially the stability of polymer composite materials under high-temperature conditions, which limits their widespread application in high-temperature fields. Summary of the Invention

[0009] To address the aforementioned problems, the purpose of this invention is to overcome the shortcomings of existing flexible sensors, such as complex structures, cumbersome fabrication processes, and limited functionality, thereby providing a flexible sensor with a simple structure, convenient fabrication, and diverse functions, as well as its fabrication method.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A flexible sensor, comprising:

[0012] The high-temperature resistant fabric 101 and the sensing carbon film layer 102 are used as the substrate of the flexible sensor. The sensing carbon film layer 102 has a pattern corresponding to the sensing function of the flexible sensor and covers the high-temperature resistant fabric 101.

[0013] In the above technical solution, the high-temperature resistant fabric 101 is made of quartz fiber, alumina fiber or basalt fiber.

[0014] In the above technical solution, the thickness of the sensing carbon film layer 102 is greater than 0 micrometers and less than or equal to 50 micrometers.

[0015] In the above technical solution, the sensing carbon film layer 102 is an SP2 hybrid structure, or an SP3 hybrid structure, or both SP2 and SP3 hybrid structures exist simultaneously.

[0016] In the above technical solution, the sensing carbon film layer 102 is doped with at least one of N and P elements.

[0017] The present invention also provides a method for fabricating the flexible sensor, comprising:

[0018] A carbon film layer is attached to the surface of the high-temperature resistant fabric 101;

[0019] A portion of the carbon film layer is removed according to a preset pattern to obtain a sensing carbon film layer 102; wherein, the high-temperature resistant fabric 101 and the sensing carbon film layer 102 constitute a flexible sensor, and the flexible sensor has a sensing function corresponding to the pattern.

[0020] In the above technical solution, attaching a carbon film layer to the surface of the high-temperature resistant fabric 101 includes:

[0021] The high-temperature resistant fabric 101 is placed inside a high-temperature tube furnace; wherein the high-temperature tube furnace is a closed structure with a gas passage on one side.

[0022] After the high-temperature tubular furnace is evacuated, protective gas is introduced through the gas channel;

[0023] The high-temperature tubular furnace is heated, and after the temperature inside the furnace reaches a first predetermined temperature value, a reducing gas and an airflow containing carbon source molecules are introduced through the gas channel; the carbon source molecules are catalytically cracked to generate positively charged active carbon groups, and the active carbon groups are attached to the surface of the high-temperature resistant fabric 101.

[0024] When the reaction time reaches the first termination condition, the gas flow containing carbon source molecules is stopped from being introduced into the high-temperature tubular furnace;

[0025] The high-temperature tubular furnace is stopped, and after cooling, a high-temperature resistant fabric 101 with a carbon film layer attached to its surface is obtained.

[0026] In the above technical solution, between the step of stopping the gas flow containing carbon source molecules into the high-temperature tubular furnace when the reaction time reaches the first termination condition and the step of stopping the operation of the high-temperature tubular furnace, and obtaining a high-temperature resistant fabric (101) with a carbon film layer attached to its surface after cooling, the method further includes:

[0027] The furnace temperature of the high-temperature tubular furnace is reduced to a second predetermined temperature value, and the furnace temperature is maintained at the second predetermined temperature value until the reaction time reaches a second termination condition; wherein the second predetermined temperature value is lower than the first predetermined temperature value.

[0028] In the above technical solution, the step of removing a portion of the carbon film layer according to a preset pattern to obtain the sensing carbon film layer 102 includes:

[0029] The high-temperature resistant fabric 101 with a carbon film layer is placed in the laser direct writing device;

[0030] The laser direct writing device is controlled according to a preset pattern so that the laser emitted by the laser direct writing device removes a portion of the carbon film layer, forming a sensing carbon film layer 102 with the same shape as the preset pattern.

[0031] The present invention has the following advantages due to the adoption of the above technical solutions:

[0032] 1. The flexible sensor of the present invention has a simple structure and can sense different physical quantities by setting the pattern of the sensing carbon film layer. It has the advantages of simple process and simple preparation.

[0033] 2. The flexible sensor of the present invention comprises a high-temperature resistant fabric and a sensing carbon film layer. The sensing carbon film layer covers the surface of the high-temperature resistant fabric, thereby forming a carbon conductive layer on the surface of the high-temperature resistant fabric. The presence of the carbon conductive layer not only improves the mechanical properties, wear resistance, and corrosion resistance of the flexible sensor, but also endows it with excellent conductivity.

[0034] 3. The sensing carbon film layer in the flexible sensor of the present invention can be doped with elements such as N and P. By doping with elements such as N and P, the sensing carbon film layer has the ability to tune the surface resistance, thereby realizing precise control of the sensitivity of the flexible sensor and expanding its application scenarios.

[0035] 4. The sensing carbon film layer in the flexible sensor of this invention can be either an SP2 hybrid structure or an SP3 hybrid structure, or both SP2 and SP3 hybrid structures can coexist. This allows the flexible sensor to be used in both everyday low-temperature environments and industrial high-temperature environments, exhibiting an extremely wide temperature range. In particular, when the sensing carbon film layer is a graphene layer, the flexible sensor of this invention can also be applied to sensor applications requiring high temperature resistance, acid and alkali resistance, salt resistance, and organic solvent resistance. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the flexible sensor of the present invention;

[0038] Figure 2 This is a schematic diagram of the flexible sensor for sensing temperature values ​​according to the present invention;

[0039] Figure 3 This is a schematic diagram of the flexible sensor for transmitting force values ​​according to the present invention;

[0040] Figure 4 This is a schematic diagram of the flexible sensor for sensing liquid chemicals according to the present invention;

[0041] Figure 5 This is a schematic diagram of the flexible sensor for sensing gaseous chemical substances according to the present invention;

[0042] Figure 6 This is a schematic diagram of the flexible sensor for sensing solid chemical substances according to the present invention;

[0043] Figure 7 This is a schematic diagram of the flexible sensor for sensing pressure values ​​according to the present invention;

[0044] Figure 8 This is a schematic diagram of the flexible sensor of the present invention for sensing deformation values;

[0045] Figure 9 This is a schematic diagram of the flexible sensor of the present invention that includes multiple sensing functions;

[0046] Figure 10 This is a flowchart of the method for fabricating the flexible sensor of the present invention;

[0047] Figure 11 A schematic diagram of the apparatus for preparing a carbon film layer to be attached to the surface of a high-temperature resistant fabric;

[0048] Figure 12 This is a schematic diagram of the structure of a laser direct writing device;

[0049] Figure 13 A scanning electron microscope image of the surface of the quartz fabric covered with a carbon film obtained in Example 1;

[0050] Figure 14 This is the Raman spectrum of the carbon film layer on the surface of basalt fabric. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0052] Figure 1 This is a schematic diagram of the flexible sensor structure of the present invention, as shown below. Figure 1As shown in the figure, the flexible sensor of the present invention includes a high-temperature resistant fabric 101 and a sensing carbon film layer 102; wherein, the high-temperature resistant fabric 101 is the substrate of the flexible sensor, and the sensing carbon film layer 102 has a pattern corresponding to the sensing function of the flexible sensor, and the sensing carbon film layer 102 covers the high-temperature resistant fabric 101.

[0053] The high-temperature resistant fabric 101 has the characteristics of flexibility and high temperature resistance, and it can be made of materials such as quartz fiber, alumina fiber, basalt fiber, etc. Quartz fiber can be preferably used in the embodiments of the present invention.

[0054] The sensing carbon film layer 102 is used to sense external physical quantities. The external physical quantities include temperature, stress, pressure, deformation, liquid chemical substances, gas chemical substances, solid chemical substances, etc. The specific type of physical quantity sensed by the sensing carbon film layer 102 is related to the pattern of the sensing carbon film layer 102. As Figure 2 shown, when the pattern of the sensing carbon film layer 102 is a symmetrically connected triangular flag structure, it is used to sense the external temperature value; as Figure 3 shown, when the pattern of the sensing carbon film layer 102 is an "H" - shaped structure, it is used to sense the external stress value; as Figure 4 shown, when the pattern of the sensing carbon film layer 102 is a square topological structure, it is used to sense external liquid chemical substances; as Figure 5 shown, when the pattern of the sensing carbon film layer 102 is an interdigital structure, it is used to sense external gas chemical substances; as Figure 6 shown, when the pattern of the sensing carbon film layer 102 is a central circle radial structure, it is used to sense external solid chemical substances; as Figure 7 shown, when the pattern of the sensing carbon film layer 102 is a symmetric bulb - shaped structure, it is used to sense the external pressure value; as Figure 8 shown, when the pattern of the sensing carbon film layer 102 is a hollowed - out structure of the character "曰", it is used to sense the external deformation value.

[0055] Sensing carbon film layers 102 with different patterns can be simultaneously distributed on the same flexible sensor. As Figure 9 shown, on the high - temperature resistant fabric of a flexible sensor, sensing carbon film layers 102 with multiple patterns are simultaneously covered, so that the flexible sensor can simultaneously sense multiple physical quantities such as temperature, stress, pressure, deformation, liquid chemical substances, gas chemical substances, solid chemical substances, etc. The pattern of the sensing carbon film layer 102 is not limited to Figure 2 — Figure 8 shown, and can be adjusted according to the actual application situation.

[0056] The thickness of the sensing carbon film layer 102 is greater than 0 micrometers and less than or equal to 50 micrometers.

[0057] The sensing carbon film layer 102 has an SP2 hybrid structure (such as graphene or graphite), or an SP3 hybrid structure (such as glassy carbon or diamond), or a combination of both SP2 and SP3 hybrid structures. In this embodiment, graphene with an SP2 hybrid structure is preferred. This allows the flexible sensor of the present invention to be used in both everyday low-temperature environments and industrial high-temperature environments, exhibiting an extremely wide temperature range. When the sensing carbon film layer 102 is a graphene layer (i.e., the entire carbon film layer is a graphite-like structure), the flexible sensor can also be applied to sensor applications requiring high temperature resistance, acid and alkali resistance, salt resistance, and organic solvent resistance.

[0058] The sensing carbon film layer 102 can be doped with at least one of N and P elements. By doping with N, P and other elements, the sensing carbon film layer 102 has the ability to tune the surface resistance, thereby realizing precise control of the sensitivity of the flexible sensor and expanding its application scenarios.

[0059] The flexible sensor of the present invention has a simple structure and can sense different physical quantities by setting the pattern of the sensing carbon film layer. It has the advantages of simple process and simple preparation.

[0060] The flexible sensor of the present invention comprises a high-temperature resistant fabric 101 and a sensing carbon film layer 102. The sensing carbon film layer 102 covers the surface of the high-temperature resistant fabric 101, thereby forming a carbon conductive layer on the surface of the high-temperature resistant fabric 101. The presence of the carbon conductive layer not only improves the mechanical properties, wear resistance, and corrosion resistance of the flexible sensor, but also endows it with excellent conductivity.

[0061] The fabrication method of the flexible sensor of the present invention will be described below.

[0062] Figure 10 The flowchart shows the fabrication method of the flexible sensor of the present invention. Figure 10 As shown, the method includes the following steps:

[0063] Step 1001: Attach a carbon film layer to the surface of the high-temperature resistant fabric 101.

[0064] There are various methods for attaching a carbon film layer to the surface of the high-temperature resistant fabric 101, such as coating, chemical vapor deposition, ion sputtering, or magnetron sputtering. In other embodiments of the present invention, the process of attaching a carbon film layer to the surface of the high-temperature resistant fabric will be described using chemical vapor deposition as an example.

[0065] Step 1002: Remove a portion of the carbon film layer according to the preset pattern to obtain the sensing carbon film layer 102; wherein, the high-temperature resistant fabric 101 and the sensing carbon film layer 102 constitute a flexible sensor, and the flexible sensor has a sensing function corresponding to the pattern.

[0066] As mentioned in the previous description of flexible sensors, the pattern of the sensing carbon film layer 102 in a flexible sensor determines the physical quantity that the flexible sensor can sense. Therefore, in the process of fabricating a flexible sensor, it is necessary to process the pattern of the carbon film layer obtained in step 1001 according to the sensing function of the flexible sensor to form a sensing carbon film layer corresponding to the sensing function.

[0067] The sensing carbon film layer 102 obtained in this step, together with the high-temperature resistant fabric 101 to which it is attached, constitutes a flexible sensor.

[0068] The flexible sensor fabrication method of the present invention has the advantages of simple fabrication process and easy implementation; the flexible sensor fabricated by the flexible sensor fabrication method of the present invention can form a carbon conductive layer on the surface of high temperature resistant fabric 101. The presence of the carbon conductive layer can not only improve the mechanical properties, wear resistance and corrosion resistance of the flexible sensor, but also endow it with excellent conductivity.

[0069] Based on any of the above embodiments, in another embodiment of the present invention, step 1001 includes:

[0070] Step 1001-1: Place the high-temperature resistant fabric 101 inside the high-temperature tube furnace; wherein the high-temperature tube furnace is a closed structure with a gas channel on one side.

[0071] Step 1001-2: After evacuating the high-temperature tubular furnace, introduce protective gas through the gas channel;

[0072] Step 1001-3: Heat the high-temperature tubular furnace. After the temperature inside the furnace reaches the first predetermined temperature value, introduce reducing gas and gas flow containing carbon source molecules through the gas channel. The carbon source molecules are catalytically cracked to generate positively charged active carbon groups, which are attached to the surface of the high-temperature resistant fabric 101.

[0073] Step 1001-4: When the reaction time reaches the first termination condition, stop the gas flow containing carbon source molecules into the high-temperature tubular furnace;

[0074] Step 1001-5: Stop the operation of the high-temperature tubular furnace and, after cooling, obtain a high-temperature resistant fabric 101 with a carbon film layer attached to its surface.

[0075] There are various methods for attaching a carbon film layer to the surface of the high-temperature resistant fabric 101. In this embodiment, chemical vapor deposition is used as an example to illustrate this process.

[0076] Before detailing the process of attaching a carbon film to the surface of high-temperature resistant fabrics, we will first introduce the equipment required to achieve this process.

[0077] Figure 11A schematic diagram of the apparatus for preparing a carbon film layer to be attached to the surface of a high-temperature resistant fabric. Figure 11 As shown, the preparation apparatus includes a high-temperature tube furnace 1101 and a gas channel 1102; wherein, the high-temperature tube furnace 1101 is a closed structure, and a gas channel 1102 is provided on one side.

[0078] When attaching a carbon film layer to the surface of the high-temperature resistant fabric 101 using this device, blank high-temperature resistant fabric 1104 is first selected, such as quartz fiber YS / QW100-100 and YS / QW100-200, 610 alumina fiber and 720 alumina fiber, basalt fiber TBW / 130 / 80 / P and TBW / 160 / 80 / P, etc.

[0079] Secondly, the blank high-temperature resistant fabric 1104 is placed inside the high-temperature tube furnace 1101. When placing it, the blank high-temperature resistant fabric 1104 can be rolled up and placed in a way that its long axis is in the same direction as the axis of the high-temperature tube furnace 1101, so that the surface of the blank high-temperature resistant fabric 1104 can be covered with a carbon film layer over a large area.

[0080] Next, the high-temperature tubular furnace 1101 is evacuated, and a protective gas is introduced through the gas channel 1102. The protective gas is an inert gas, such as argon or nitrogen.

[0081] Then, the high-temperature tube furnace 1101 is heated. After the temperature inside the furnace reaches the first predetermined temperature value, reducing gas and gas flow containing carbon source molecules are introduced through the gas channel 1102. After the carbon source molecules are catalytically cracked, positively charged active carbon groups 1103 are generated. The active carbon groups 1103 adhere to the surface of the high-temperature resistant fabric 101, nucleate, and grow into a carbon film layer 1105.

[0082] The first predetermined temperature value is the reaction temperature value of the high-temperature tube furnace 1101, which is typically greater than or equal to 600°C and less than or equal to 1000°C. Within this reaction temperature range, the higher the first predetermined temperature value, the easier it is to form a carbon film layer. That is, under the same conditions, the higher the first predetermined temperature value, the greater the thickness of the carbon film layer 1105.

[0083] The carbon source is selected from at least one of gaseous carbon sources (such as methane, ethylene, acetylene), solid carbon sources (such as polyaniline, polystyrene), and liquid carbon sources (such as toluene, benzoic acid, chlorobenzene, ethanol, acetonitrile). The reducing gas includes hydrogen, ammonia, etc.

[0084] Carbon source molecules undergo catalytic cracking at high temperatures to produce active carbon groups 1103. These active carbon groups 1103, adsorbed on the surface of the high-temperature resistant fabric 101, undergo nucleation and growth processes to form a dense, vertically structured carbon protective layer, thus forming the carbon film layer 1105. Non-carbon groups obtained from the catalytic cracking of carbon source molecules at high temperatures are discharged as waste products. The concentration of carbon source molecules in the airflow is related to the ease of carbon film layer formation; a higher concentration makes carbon film layer formation easier. In other words, under the same conditions, a higher carbon source molecule concentration results in a thicker carbon film layer 1105.

[0085] Then, when the reaction time reaches the first termination condition, the gas flow containing carbon source molecules is stopped from being introduced into the high-temperature tubular furnace 1101. Activated carbon groups 1103 are adsorbed onto the surface of the high-temperature resistant fabric 101, forming a dense carbon film layer through nucleation and growth processes within a specific reaction time. This specific reaction time is the first termination condition (the value of the first termination condition ranges from 1 min to 120 min). At this point, the gas flow containing carbon source molecules can be stopped from being introduced into the high-temperature tubular furnace 1101, thereby stopping the process of activated carbon groups 1103 adsorbing onto the surface of the high-temperature resistant fabric 101.

[0086] Finally, the operation of the high-temperature tube furnace 1101 is stopped, and after cooling, a high-temperature resistant fabric 101 with a carbon film layer 1105 attached to its surface is obtained. Specifically, the heating process of the high-temperature tube furnace 1101 is stopped, causing the temperature inside the furnace to gradually decrease, while the protective gas and reducing gas are still transported into the high-temperature tube furnace 1101 through the gas channel 1102; the product of adsorbed activated carbon groups 1103 undergoes nucleation and growth, and after natural cooling, the desired high-temperature resistant fabric 101 covered with a carbon film layer 1105 is finally obtained. The carbon film layer 1105 generally contains both a graphite-like structure (SP2) and a diamond-like structure (SP3).

[0087] The above is a detailed explanation of the process of attaching a carbon film layer to the surface of the high-temperature resistant fabric 101.

[0088] The flexible sensor fabrication method of the present invention has the advantages of simple fabrication process and easy implementation.

[0089] Based on any of the above embodiments, in this embodiment, between step 1001-4 and step 1001-5, the method further includes:

[0090] The furnace temperature of the high-temperature tubular furnace 1101 is reduced to a second predetermined temperature value, and the furnace temperature is maintained at the second predetermined temperature value until the reaction time reaches a second termination condition; wherein the second predetermined temperature value is lower than the first predetermined temperature value.

[0091] In this embodiment, after the gas flow containing carbon source molecules is stopped from the high-temperature tubular furnace 1101, the protective gas and reducing gas continue to be input into the high-temperature tubular furnace 1101 through the gas channel 1102. Simultaneously, the furnace temperature of the high-temperature tubular furnace 1101 is reduced from a previously higher first predetermined temperature value to a lower second predetermined temperature value. For example, if the first predetermined temperature value is 1000°C, the second predetermined temperature value is 600°C. This second furnace temperature value is maintained for a period of time to allow the reaction time to reach the second termination condition (the time corresponding to the second termination condition is generally 10 to 90 minutes after the time corresponding to the first termination condition; in one embodiment, it can be 30 minutes). At this point, the operation of the high-temperature tubular furnace is stopped, allowing the furnace temperature to gradually decrease. Meanwhile, the protective gas and reducing gas continue to be transferred into the high-temperature tubular furnace 1101 through the gas channel 1102. After cooling, a high-temperature resistant fabric 101 with a carbon film layer attached to its surface is obtained.

[0092] In this embodiment, based on the high-temperature resistant fabric with a carbon film layer prepared in the previous embodiment, the fabric is heat-insulated at a second predetermined temperature value lower than the first predetermined temperature value. This increases the proportion of graphite-like structures (SP2) in the carbon film layer (i.e., reduces the proportion of diamond-like structures (SP3) in the carbon film layer), thereby controlling the resistivity of the high-temperature resistant fabric surface and enabling the flexible sensor to be used in different application scenarios. Generally, the longer the heat-insulating time of the high-temperature resistant fabric with a carbon film layer at the second predetermined temperature value, the higher the proportion of graphite-like structures (SP2) in the carbon film layer.

[0093] Further optimization of temperature, pressure, atmosphere composition, and reaction time can achieve carbon atom docking, localized diffusion, and crystallization, thus completing the growth of graphene. This expands the application of flexible sensors in fields such as high-temperature resistance, acid and alkali resistance, salt resistance, and organic solvent resistance.

[0094] The flexible sensor fabrication method of the present invention increases the proportion of graphite-like structures (SP2) in the carbon film layer by heat preservation treatment of the high-temperature resistant fabric covering the carbon film layer during the fabrication process, thereby controlling the resistivity of the surface of the high-temperature resistant fabric and expanding the application field of the flexible sensor.

[0095] Based on any of the above embodiments, in another embodiment of the present invention, step 1002 includes:

[0096] Step 1002-1: Place the high-temperature resistant fabric 101 with the carbon film layer attached into the laser direct writing device;

[0097] Step 1002-2: Control the laser direct writing device according to the preset pattern so that the laser emitted by the laser direct writing device removes part of the carbon film layer to form a sensing carbon film layer 102 with the same shape as the preset pattern.

[0098] Before detailing the process of generating the sensing carbon film, we will first introduce the equipment required to achieve this process.

[0099] Figure 12 This is a schematic diagram of the structure of a laser direct writing device, such as... Figure 12 As shown, the laser direct writing device includes: a positioning buckle 1201, a laser 1202, and a controller 1205; wherein, the positioning buckle 1201 is used to adjust the distance between the laser 1202 and the high-temperature resistant fabric 101 covered with a carbon film layer; the laser 1202 can emit laser light 1203 of a specific wavelength; by inputting a preset program into the controller 1205, a preset pattern can be processed on the high-temperature resistant fabric 101 covered with a carbon film layer.

[0100] The laser 1203 emitted by the laser 1202 at a specific wavelength can be an ultraviolet laser or an infrared laser.

[0101] The specific process of generating a sensing carbon film layer 102 on a high-temperature resistant fabric 101 coated with a carbon film layer using a laser direct writing device is as follows:

[0102] First, the high-temperature resistant fabric 101 with a carbon film layer obtained in step 1001 is placed on the table 1206 of the laser direct writing device. The positioning buckle 1201 is adjusted to control the distance between the laser 1202 and the surface of the high-temperature resistant fabric 101 with the carbon film layer to be the focal length of the laser direct writing device. A control command corresponding to a preset pattern is input into the controller 1205 of the laser direct writing device. The preset pattern is a pattern corresponding to the sensing function of the flexible sensor. The sensing function includes sensing one or more of multiple physical quantities such as temperature, stress, pressure, deformation, liquid chemical substances, gaseous chemical substances, and solid chemical substances.

[0103] Next, the laser direct writing device begins the laser direct writing process. The laser 1203 of a specific wavelength emitted by the laser 1202 removes a portion of the carbon film layer on the surface of the high-temperature resistant fabric 101 covered with the carbon film layer according to the control command corresponding to the preset pattern, thereby forming a sensing carbon film layer 102 that is consistent with the shape of the preset pattern.

[0104] Finally, when the laser direct writing time reaches the third termination condition, the laser direct writing process is stopped, the laser 1202 is turned off, and the redundant high-temperature resistant fabric 101 is cut off to obtain the required flexible sensor.

[0105] In this step, laser 1202 emits a specific wavelength laser 1203. Within a specific laser direct writing time, according to the control command in controller 1205, a specific area of ​​the carbon film layer covering the high-temperature resistant fabric 101 is removed, resulting in a sensing carbon film layer 102 with a shape consistent with the preset pattern. This specific laser direct writing time is the third termination condition, and the value of the third termination condition ranges from 1 min to 90 min.

[0106] The flexible sensor fabrication method of the present invention utilizes programmable laser direct writing technology to locally etch a carbon film layer and print out diverse sensor patterns, thereby realizing the sensing of various physical quantities such as temperature, pressure, and stress.

[0107] The present invention will be further described below with reference to specific embodiments.

[0108] Example 1

[0109] The high-temperature tube furnace was evacuated to 0.5 Pa, and 50 sccm of argon gas was introduced as a protective gas. The blank quartz fabric substrate to be grown was rolled up and placed with its long axis aligned with the tube furnace. The high-temperature tube furnace was then heated to 800℃, and 100 sccm of ethylene gas was introduced as a carbon source, while 200 sccm of hydrogen gas was introduced as a reducing gas. The reaction time was 40 min.

[0110] Under high-temperature conditions, carbon source gas molecules decompose into various active carbon groups, which are adsorbed onto the surface of the quartz fabric substrate. After nucleation and growth processes, a carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. Under argon and hydrogen atmospheres, the reaction product is naturally cooled to room temperature and then removed to obtain the quartz fabric with the desired carbon film layer on its surface.

[0111] Subsequently, programmable laser direct writing technology is used to ablate the temperature sensor pattern on the surface of a quartz fabric covered with a carbon film layer using a 200-300nm laser according to the pre-input program in the control computer, thus obtaining a high-temperature resistant flexible temperature sensor.

[0112] The obtained quartz fabric covered with a carbon film layer was characterized. Figure 13 This is a scanning electron microscope (SEM) image of the quartz fabric surface covered with a carbon film obtained in Example 1. A uniform carbon film layer is grown on the surface of the quartz fibers, exhibiting a typical warp and weft weave structure. The sheet resistivity of the prepared quartz fabric sample with the carbon film layer was measured. Its sheet resistivity was 400-500 Ω, indicating good conductivity.

[0113] Example 2

[0114] The high-temperature tubular furnace was evacuated to 0.5 Pa, and 50 sccm of argon gas was introduced as a protective gas. The blank basalt fabric substrate to be grown was rolled up and placed with its long axis aligned with the tubular furnace. The high-temperature tubular furnace was then heated to 800℃, and 100 sccm of ethylene gas was introduced as a carbon source, while 100 sccm of hydrogen gas was introduced as a reducing gas. The reaction time was 30 min.

[0115] Under high-temperature conditions, carbon source gas molecules decompose into various active carbon groups, which are adsorbed onto the surface of the basalt fabric substrate. After nucleation and growth processes, a carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. The temperature of the tube furnace is reduced to 600°C under argon and hydrogen conditions. The reaction product is held at this temperature for 30 minutes and then naturally cooled to room temperature before being removed, yielding the quartz fabric with the desired carbon film layer on its surface.

[0116] Subsequently, programmable laser direct writing technology was employed, using an 800-900nm laser to ablate stress sensor patterns onto the surface of basalt fabric covered with a carbon film, according to a pre-input program in the control computer. This resulted in a flexible stress sensor with excellent high-temperature resistance. The prepared basalt fabric sample with a carbon film surface was then subjected to sheet resistivity testing. Its sheet resistivity was 200-300Ω, indicating good conductivity.

[0117] Example 3

[0118] The high-temperature tube furnace was evacuated to 0.5 Pa, and 50 sccm of argon gas was introduced as a protective gas. The blank alumina fabric substrate to be grown was rolled up and placed with its long axis aligned with the tube furnace. The high-temperature tube furnace was then heated to 1000℃, and 100 sccm of ethanol vapor was introduced as a carbon source, while 100 sccm of hydrogen gas was introduced as a reducing gas. The reaction time was 30 min.

[0119] Under high-temperature conditions, carbon source gas molecules decompose into various active carbon groups, which are adsorbed onto the surface of the alumina fabric substrate. After nucleation and growth processes, a carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. The temperature of the tube furnace is reduced to 800℃ under argon and hydrogen conditions. The reaction product is held at this temperature for 30 minutes and then naturally cooled to room temperature before being removed, yielding the alumina fabric with the desired carbon film layer on its surface.

[0120] Subsequently, programmable laser direct writing technology was employed, using a 1053nm laser to ablate the sensor array (e.g., ...) onto the surface of an alumina fabric covered with a carbon film layer, according to a pre-input program in the control computer. Figure 9As shown, an integrated high-temperature resistant flexible sensor with different functions was obtained. The surface resistivity of the prepared alumina fabric sample with a carbon film coating was tested. Its surface resistivity was 75-100Ω, indicating good conductivity.

[0121] Example 4

[0122] The high-temperature tube furnace was evacuated to 0.5 Pa, and 50 sccm of argon gas was introduced as a protective gas. The blank quartz fabric substrate to be grown was rolled up and placed with its long axis aligned with the tube furnace. The high-temperature tube furnace was then heated to 1000℃, and 200 sccm of ethanol vapor was introduced as a carbon source, while 100 sccm of hydrogen gas was introduced as a reducing gas. The reaction time was 30 min.

[0123] Under high-temperature conditions, carbon source gas molecules decompose into various active carbon groups, which are adsorbed onto the surface of the quartz fabric substrate. After nucleation and growth processes, a carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. The temperature of the tube furnace is reduced to 800°C under argon and hydrogen conditions. The reaction product is held at this temperature for 60 minutes and then naturally cooled to room temperature before being removed, yielding the quartz fabric with the desired carbon film layer on its surface.

[0124] Subsequently, programmable laser direct writing technology was used to ablate the gas sensor pattern on the surface of a quartz fabric covered with a carbon film layer using a 1053nm laser according to the pre-input program in the control computer, thus obtaining a high-temperature resistant flexible gas sensor.

[0125] Example 5

[0126] The high-temperature tube furnace was evacuated to 1 Pa, and 50 sccm of nitrogen was introduced as a protective gas. The blank alumina fabric substrate to be grown was rolled up and placed with its long axis aligned with the tube furnace. The high-temperature tube furnace was then heated to 600°C, and 200 sccm of methane was introduced as a carbon source, while 20 sccm of hydrogen was introduced as a reducing gas. The reaction time was 120 min.

[0127] Under high-temperature conditions, carbon source gas molecules decompose into various active carbon groups, which are adsorbed onto the surface of the alumina fabric substrate. After nucleation and growth processes, a carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. Under argon and hydrogen atmospheres, the reaction product is naturally cooled to room temperature and then removed to obtain the desired alumina fabric with a carbon film layer on its surface.

[0128] Subsequently, programmable laser direct writing technology was used to ablate the deformation sensor pattern on the surface of the alumina fabric covered with a carbon film layer using a 1047nm laser according to the pre-input program in the control computer, thus obtaining a high-temperature resistant flexible deformation sensor.

[0129] Example 6

[0130] The high-temperature tubular furnace was evacuated to 1 Pa, and 50 sccm of nitrogen gas was introduced as a protective gas. The blank basalt fabric substrate to be grown was rolled up and placed with its long axis aligned with the tubular furnace. The high-temperature tubular furnace was then heated to 800°C, and 200 sccm of gas containing methane and acetonitrile vapor was introduced as the carbon source and nitrogen source, respectively. At the same time, 50 sccm of hydrogen gas was introduced as the reducing gas. The reaction time was 1 min.

[0131] Under high-temperature conditions, methane vapor molecules decompose into various active carbon groups, and acetonitrile decomposes to produce nitrogen-containing active groups, which are adsorbed onto the surface of the basalt fabric substrate. After nucleation and growth processes, a nitrogen-doped carbon film layer with excellent conductivity, wear resistance, and corrosion resistance is gradually formed. After the reaction is completed, the carbon source is turned off. The temperature of the tube furnace is reduced to 600°C under argon and hydrogen atmospheres. The reaction product is held at this temperature for 30 minutes and then naturally cooled to room temperature before being removed, yielding the desired basalt fabric with a nitrogen-doped carbon film layer on its surface.

[0132] Subsequently, programmable laser direct writing technology was used to ablate the pressure sensor pattern on the surface of basalt fabric covered with a carbon film layer using a 1064nm laser according to the pre-input program in the control computer, thus obtaining a high-temperature resistant flexible pressure sensor.

[0133] The obtained basalt fabric covered with carbon film was characterized. Figure 14 The image shows the Raman spectrum of the carbon film layer on the surface of the basalt fabric. The G peak indicates that the grown carbon film layer is composed of sp2 hybrid carbon atoms, and the low-intensity 2D peak indicates that the carbon film layer is multilayer graphene.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible sensor, characterized in that, include: The high-temperature resistant fabric (101) and the sensing carbon film layer (102) are used as the substrate of the flexible sensor. The sensing carbon film layer (102) has a pattern corresponding to the sensing function of the flexible sensor and covers the high-temperature resistant fabric (101).

2. The flexible sensor according to claim 1, characterized in that, The high-temperature resistant fabric (101) is made of quartz fiber, alumina fiber or basalt fiber.

3. The flexible sensor according to claim 1, characterized in that, The thickness of the sensing carbon film layer (102) is greater than 0 micrometers and less than or equal to 50 micrometers.

4. The flexible sensor according to claim 1, characterized in that, The sensing carbon film layer (102) is an SP2 hybrid structure, or an SP3 hybrid structure, or both SP2 and SP3 hybrid structures exist simultaneously.

5. The flexible sensor according to claim 1, characterized in that, The sensing carbon film layer (102) is doped with at least one of N and P elements.

6. A method for preparing a flexible sensor according to any one of claims 1 to 5, characterized in that, include: A carbon film layer is attached to the surface of the high-temperature resistant fabric (101); A portion of the carbon film layer is removed according to a preset pattern to obtain a sensing carbon film layer (102); wherein, the high-temperature resistant fabric (101) and the sensing carbon film layer (102) constitute a flexible sensor, and the flexible sensor has a sensing function corresponding to the pattern.

7. The method for fabricating a flexible sensor according to claim 6, characterized in that, The process of attaching a carbon film layer to the surface of the high-temperature resistant fabric (101) includes: The high-temperature resistant fabric (101) is placed inside a high-temperature tube furnace; wherein the high-temperature tube furnace is a closed structure and a gas channel is provided on one side. After the high-temperature tubular furnace is evacuated, protective gas is introduced through the gas channel; The high-temperature tubular furnace is heated, and after the temperature inside the furnace reaches a first predetermined temperature value, a reducing gas and an airflow containing carbon source molecules are introduced through the gas channel; the carbon source molecules are catalytically cracked to generate positively charged active carbon groups, and the active carbon groups are attached to the surface of the high-temperature resistant fabric (101). When the reaction time reaches the first termination condition, the gas flow containing carbon source molecules is stopped from being introduced into the high-temperature tubular furnace; The high-temperature tubular furnace is stopped and cooled to obtain a high-temperature resistant fabric (101) with a carbon film layer attached to its surface.

8. The method for fabricating a flexible sensor according to claim 7, characterized in that, Between the steps of stopping the gas flow containing carbon source molecules into the high-temperature tubular furnace when the reaction time reaches the first termination condition and stopping the operation of the high-temperature tubular furnace, and obtaining a high-temperature resistant fabric (101) with a carbon film layer attached to its surface after cooling, the method further includes: The furnace temperature of the high-temperature tubular furnace is reduced to a second predetermined temperature value, and the furnace temperature is maintained at the second predetermined temperature value until the reaction time reaches a second termination condition; wherein the second predetermined temperature value is lower than the first predetermined temperature value.

9. The method for fabricating a flexible sensor according to claim 6, characterized in that, The step of removing a portion of the carbon film layer according to a preset pattern to obtain the sensing carbon film layer (102) includes: The high-temperature resistant fabric (101) with a carbon film layer is placed in the laser direct writing device; The laser direct writing device is controlled according to a preset pattern so that the laser emitted by the laser direct writing device removes a portion of the carbon film layer, forming a sensing carbon film layer (102) with the same shape as the preset pattern.

Images