A fast response flexible temperature sensor with low thermal cross-talk and a method of making the same

Abstract

The application discloses a fast-response flexible temperature sensor with low thermal crosstalk and a preparation method thereof. The sensor comprises a contact layer, a sensing layer, an electrode layer and a substrate layer. The contact layer comprises a heat-conducting layer and a heat-insulating network. The heat-conducting layer is made of a heat-conducting composite material, which comprises polydimethylsiloxane and flaky carbon powder. The heat-insulating network and the substrate layer are made of a heat-insulating composite material, which comprises polydimethylsiloxane and hollow glass microspheres. The sensing layer comprises a plurality of sensing units arranged in an array. The sensing units are connected with the electrode layer and output resistance signals. The heat-conducting layer and the substrate layer are arranged above and below the sensing units, respectively. The heat-conducting and heat-insulating collaborative structure can enhance the fast response of the sensing units to temperature. The heat-insulating network is embedded in the contact layer to block the thermal crosstalk between adjacent sensing units. The temperature sensor has the advantages of fast response, low thermal crosstalk and high reliability in a wide range, and can be prepared in a large scale.

Description

Technical Field

[0001] This invention belongs to the field of flexible temperature sensor technology, and in particular relates to a fast-response flexible temperature sensor with low thermal crosstalk for wide temperature range scenarios and its fabrication method. Background Technology

[0002] Flexible temperature sensors have attracted widespread attention from researchers in recent years due to their high adaptability and flexibility, which have great application potential in smart healthcare, smart robotics, and industrial production. Nevertheless, compared to traditional rigid temperature sensors, flexible devices still face many bottlenecks.

[0003] On the one hand, current research on flexible temperature sensors is mostly focused on health monitoring, resulting in narrow measurement ranges and slow response times. Secondly, large-area, arrayed flexible sensors can be used to measure temperature distribution, playing a crucial role in robot perception and interaction; however, inter-unit thermal crosstalk reduces measurement accuracy. Furthermore, flexible temperature sensors suffer from insufficient reliability and stability in multi-physics coupled environments. These factors significantly limit their large-scale application in real-world scenarios.

[0004] The development and performance tuning of temperature-sensitive materials can effectively achieve a synergy between wide measurement range and linearity. Designing the sensor's encapsulation structure based on thermal management strategies and configuring appropriate encapsulation materials can improve response speed and reduce thermal crosstalk.

[0005] By combining the development of functional materials with sensor structure design, it is expected to solve problems such as wide measurement range, high linearity, fast response, low crosstalk and high reliability, and promote the development of flexible temperature sensors in this field towards high performance and high practicality. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a fast-response flexible temperature sensor with low thermal crosstalk and its fabrication method.

[0007] This invention introduces PEDOT:PSS into CNTs to form a composite conductive network. PEDOT:PSS, as a hole-conducting polymer material, can adjust the carrier transport barrier in the CNT conductive network, thus changing the temperature sensing range. The addition of R-1055 primarily modulates the rheological properties to facilitate fabrication and molding. The sensing principle of this temperature-sensitive material is based on the temperature-dependent resistance characteristics of semiconductors, exhibiting a negative temperature coefficient of resistance. As the temperature increases, the carrier concentration and mobility in the temperature-sensitive material increase, leading to a decrease in resistance. Furthermore, this temperature sensing principle is essentially unaffected by pressure, and the interlocking packaging structure design further enhances high reliability. The sensor's rapid response is based on the synergistic thermal conductivity and insulation formed by the contact layer and the substrate layer, allowing the sensing layer to reach thermal equilibrium more quickly under external thermal stimuli. In addition, the thermal insulation network embedded between different sensing units effectively blocks heat transfer, reduces thermal crosstalk, and improves temperature sensing accuracy.

[0008] The technical solution adopted in this invention is as follows: I. A fast-response flexible temperature sensor with low thermal crosstalk The temperature sensor comprises a contact layer, a sensing layer, an electrode layer, and a base layer stacked sequentially from top to bottom. The contact layer and base layer serve as the upper and lower encapsulation layers of the sensor. The contact layer, which includes a thermally conductive layer and a thermal insulation network, facilitates contact between the sensor and the object being measured. The base layer facilitates contact between the sensor and the mounting surface. The lower part of the thermally conductive layer contacts the upper part of the sensing layer to conduct heat, while the base layer is positioned below the sensing layer to minimize heat conduction between the sensing layer and the mounting surface. The thermal insulation network is embedded in the contact layer and connected to the thermally conductive layer to reduce lateral thermal crosstalk. The electrode layer provides support and electrical connection to the sensing layer.

[0009] The contact layer and the base layer are designed with a concave-convex interlocking snap-fit ​​structure, which can contain the sensing layer and the electrode layer, and achieve a high-strength encapsulation connection through the four-sided frame; the sensing layer includes multiple sensing units arranged in a 4×4 array, and the electrode layer includes an electrode layer PI substrate and a Cu electrode pattern; the upper surface of the electrode layer PI substrate is aligned and connected with the inner surface of the groove of the contact layer, and the lower surface of the electrode layer PI substrate is aligned and connected with the upper surface of the protrusion of the base layer; the electrode layer PI substrate has a Cu electrode pattern, and each sensing unit is connected to the Cu electrode pattern and outputs a resistance signal, which can reflect temperature information.

[0010] The upper part of the sensing unit is in contact with the thermally conductive layer, enabling rapid heat conduction between the sensing unit and the object being measured; the lower part of the sensing unit is in contact with the base layer, ensuring less heat conduction between the sensing unit and the loading surface. This thermally conductive and thermally insulating synergistic structure enhances the sensing unit's rapid response to temperature; the thermal insulation network is embedded in the contact layer, limiting the heat conduction between the thermally conductive layer and the sensing unit to the area corresponding to a single sensing unit, thereby reducing lateral thermal crosstalk between adjacent sensing units.

[0011] The thermal insulation network includes multiple transverse thermal insulation strips and multiple longitudinal thermal insulation strips. In the sensor unit array, a transverse thermal insulation strip is set between every two adjacent rows of sensor units, and a longitudinal thermal insulation strip is set between every two adjacent columns of sensor units. The multiple transverse thermal insulation strips and multiple longitudinal thermal insulation strips together form a grid structure.

[0012] Each sensing unit has a serpentine structure, which adopts a bidirectional expansion design based on S-shape. Two S-shaped tracks are arranged at intervals in the horizontal and vertical directions. The tracks are connected by circular arcs of the same radius to form a smooth and continuous folding layout, so as to balance and improve the anti-interference performance of the sensing unit against horizontal and vertical strain.

[0013] The thermal conductive layer uses PDMS / FG thermal conductive composite material, the thermal insulation network and the base layer both use PDMS / HGM thermal insulation composite material, and the sensing layer uses PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material.

[0014] The PDMS / FG thermally conductive composite material is mainly composed of PDMS main agent, curing agent and flake graphite (FG, flake diameter 25-48 μm) in a mass ratio of 10:1:3. The PDMS / HGM thermal insulation composite material is mainly composed of PDMS main agent, curing agent and hollow glass microspheres (HGM, particle size 50-70 μm) in a mass ratio of 10:1:0.75. The PEDOT:PSS / CNT / R-1055 thermosensitive composite material is mainly composed of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), carbon nanotubes (CNT, diameter 1-2 nm, length 5-30 μm) and tackifier R-1055 in a mass ratio of 1:1:0.01. Both the PDMS main agent and the curing agent are polydimethylsiloxane.

[0015] II. Fabrication Method of Fast-Response Flexible Temperature Sensor with Low Thermal Crosstalk The preparation method includes the following steps: S1. Preparation of materials and molds for each layer: Prepare PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material, PDMS / FG thermally conductive composite material, and PDMS / HGM thermal insulation composite material respectively; use 3D printing technology to print molds that match the structure of each layer and each part in each layer.

[0016] The specific implementation includes the following two steps: S11, Preparation of each layer of materials: Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), carbon nanotubes (CNTs), and tackifier (R-1055) are mixed at a mass ratio of 1:1:0.01 and stirred uniformly at room temperature for 5 min to obtain the PEDOT:PSS / CNT / R-1055 thermosensitive composite material; Polydimethylsiloxane (PDMS main agent and curing agent) and flake carbon powder (FG) are mixed at a mass ratio of 10:1:3 and stirred uniformly at room temperature for 6 min, followed by 30 min of room temperature vacuum degassing treatment to obtain the PDMS / FG thermally conductive composite material; Polydimethylsiloxane (PDMS main agent and curing agent) and hollow glass microspheres (HGM) are mixed at a mass ratio of 10:1:0.75 and stirred uniformly at room temperature for 6 min. min, prepare PDMS / HGM thermal insulation composite material; S12, prepare various molds: use photopolymerization 3D printing technology to print injection molds that match the structure of each layer and each part in each layer, and clean each mold that has been made and spray release agent evenly on the mold surface for subsequent demolding.

[0017] S2. Preparation of contact layer and base layer: PDMS / HGM thermal insulation composite material is injected into the corresponding molds, and after heating and curing, it is demolded to obtain thermal insulation network and base layer; the thermal insulation network is fixed in the corresponding mold, and then PDMS / FG thermal conductive composite material is injected into the mold, and after heating and curing, it is demolded to obtain contact layer.

[0018] Specifically, PDMS / HGM thermal insulation composite material was injected into a mold matching the thermal insulation network and a mold matching the base layer, respectively. After heating at 120 ℃ for 2 h, the material was cured and demolded to obtain the thermal insulation network and the base layer. The thermal insulation network was fixed in a mold matching the thermal conductive layer using positioning assembly holes. Then, PDMS / FG thermal conductive composite material was injected into a mold matching the thermal conductive layer and cured and demolded after heating at 120 ℃ for 2 h to obtain the preliminary contact layer. Finally, two positioning mating pillars on the preliminary contact layer were removed to obtain the contact layer.

[0019] S3. Electrode layer preparation: Polyimide coating adhesive is spin-coated onto the surface of a glass plate substrate and heated to cure, thus preparing the PI electrode layer substrate. Subsequently, Cu electrode patterns are prepared on the PI electrode layer substrate by photolithography and magnetron sputtering processes to obtain the electrode layer.

[0020] Specifically, the surface of the glass plate substrate is first treated by immersing it in acetone and ethanol solutions for ultrasonic cleaning for 10 minutes each to remove organic contaminants. Then, a polyimide coating is uniformly spin-coated onto the surface and heated to cure, thus preparing an electrode layer PI substrate with a thickness of 25 μm. A Cu electrode pattern with a thickness of 200 nm is then prepared on the electrode layer PI substrate using photolithography and magnetron sputtering processes to obtain a preliminary electrode layer. Finally, the outline of the preliminary electrode layer is cut using a laser cutter to obtain the electrode layer.

[0021] S4. Preparation of the sensing layer: Place the screen printing plate on the electrode layer, and use a squeegee to transfer the PEDOT:PSS / CNT / R-1055 thermosensitive composite material to the surface of the electrode layer. After heating and curing, a sensing layer connected to the Cu electrode pattern is obtained.

[0022] Specifically, a screen printing plate is placed on the electrode layer, and the PEDOT:PSS / CNT / R-1055 thermosensitive composite material is scraped into the gaps of the screen printing plate and transferred to the surface of the electrode layer using a screen printing process. After heating at 120 °C for 1 h, it is cured to obtain a sensing layer connected to the Cu electrode pattern.

[0023] S5. Sensor assembly: After processing, the prepared layers are aligned and stacked in sequence, and then bonded under certain conditions to prepare a flexible temperature sensor. Specifically, the connecting surfaces of each layer are plasma-treated, and then the treated layers are aligned, stacked and assembled, and then heated and bonded at 120 °C for 30 min to prepare a flexible temperature sensor.

[0024] The fabricated flexible temperature sensor has a contact layer thickness of 500 μm excluding the frame and a frame thickness of 1 mm; a substrate layer thickness of 1 mm excluding the frame and a frame thickness of 500 μm; the sensing units in the sensing layer are all 8 mm × 8 mm in size and 50 μm in thickness, the serpentine structure of the sensing units has a linewidth of 400 μm, and the lateral and longitudinal spacing between two adjacent sensing units is 16 mm; the electrode layer has a PI substrate thickness of 25 μm and a Cu electrode pattern thickness of 200 nm.

[0025] The temperature sensor of the present invention can combine fast response, low thermal crosstalk and high reliability over a wide range, and can be mass-produced.

[0026] The beneficial effects of this invention are: 1) The temperature-sensitive composite material PEDOT:PSS / CNT / R-1055 developed in this invention possesses excellent sensing and rheological properties, and the flexible temperature sensor balances high sensitivity and high linearity over a wide measurement range. Furthermore, the fabrication process of the device in this invention is suitable for screen printing and injection molding, enabling large-scale production.

[0027] 2) The PDMS / FG and PDMS / HGM composite materials developed in this invention possess excellent thermal properties. The synergistic design of thermal conductivity and insulation in the contact layer and substrate layer enables the sensor to respond quickly to external stimuli. The introduction of a thermal insulation network in the contact layer ensures low thermal crosstalk between sensing units, improving sensing accuracy.

[0028] 3) The PDMS / FG and PDMS / HGM composite materials developed in this invention have matching moduli. The designed sensor interlocking packaging structure and serpentine sensing structure further improve the device packaging strength and reliability. The sensor maintains stable performance under pressure, bending and even extreme temperature changes. Attached Figure Description

[0029] Figure 1 This is a three-dimensional view showing the layered structure of the sensor of the present invention; Figure 2 In the figures (a) and (b), the relative resistance change Δ of the temperature-sensitive material of the sensor of the present invention under different ratios are respectively. R / R The graph showing the relationship between temperature and the model, along with the fitting results based on the Mott equation; Figure 3 The relative resistance change Δ of the sensing unit of the sensor of this invention is... R / R Correspondence with temperature; Figure 4 These are extreme working condition test diagrams of the sensing unit of the sensor of the present invention, wherein (a), (b), and (c) respectively represent stress loading, bending loading, and extreme temperature changes; Figure 5 This is a thermal crosstalk test diagram of the sensor of this invention; Figure 6 This is a flowchart illustrating the overall manufacturing process of the sensor of this invention; Figure 7 This is a schematic diagram of the mold used to manufacture the sensor contact layer of the present invention; Figure 8 This is a schematic diagram of the mold used to manufacture the sensor substrate layer of the present invention; Figure 9 It is the mask pattern used to manufacture the sensor sensing layer of the present invention.

[0030] In the figure: 1. Contact layer; 11. Thermal conductive layer; 12. Thermal insulation network; 2. Sensing layer; 3. Electrode layer; 31. Electrode layer PI substrate; 32. Cu electrode pattern; 4. Substrate layer; 5. Positioning and assembly hole. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] This invention provides a flexible temperature sensor with low thermal crosstalk. like Figure 1 As shown, the flexible temperature sensor includes a contact layer 1, a sensing layer 2, an electrode layer 3, and a base layer 4 stacked sequentially from top to bottom. The contact layer 1 and base layer 4 serve as the upper and lower encapsulation layers of the sensor. The contact layer 1, which is used for contact between the sensor and the object being measured, includes a thermally conductive layer 11 and a thermal insulation network 12. The base layer 4 is used for contact between the sensor and the mounting surface. The contact layer 1 and base layer 4 are designed with a snap-fit ​​structure, which can encapsulate the sensing layer 2 and the electrode layer 3, and achieve a high-strength encapsulation connection through a surrounding frame. The electrode layer 3 provides support and electrical connection for the sensing layer 2.

[0033] The sensing layer 2 includes multiple sensing units arranged in a 4×4 array. The electrode layer 3 includes an electrode layer PI substrate 31 and a Cu electrode pattern 32. The upper surface of the electrode layer PI substrate 31 is aligned and connected to the inner surface of the groove of the contact layer 1, and the lower surface of the electrode layer PI substrate 31 is aligned and connected to the upper surface of the protrusion of the base layer 4. The electrode layer PI substrate 31 is provided with a Cu electrode pattern 32, and each sensing unit is connected to the Cu electrode pattern 32 and outputs a resistance signal.

[0034] The upper part of the sensing unit is connected to the thermally conductive layer 11 to achieve rapid heat conduction between the sensing unit and the object being measured. A base layer 4 is arranged below the sensing unit to ensure less heat conduction between the sensing unit and the loading surface. This thermally conductive and thermally insulating synergistic structure can enhance the rapid response of the sensing unit to temperature. The thermal insulation network 12 is embedded in the contact layer 1 to limit the heat conduction between the thermally conductive layer 11 and the sensing unit to the area corresponding to a single sensing unit, so as to reduce lateral thermal crosstalk between adjacent sensing units.

[0035] Furthermore, the thermal insulation network 12 includes multiple transverse thermal insulation strips and multiple longitudinal thermal insulation strips. In the sensing unit array, a transverse thermal insulation strip is provided between every two adjacent rows of sensing units, and a longitudinal thermal insulation strip is provided between every two adjacent columns of sensing units. The multiple transverse thermal insulation strips and the multiple longitudinal thermal insulation strips together form a grid structure.

[0036] Furthermore, each of the sensing units is a serpentine structure, which adopts a bidirectional expansion design based on an S-shape. Two S-shaped tracks are arranged at intervals in the horizontal and vertical directions, and each track is connected by a circular arc of the same radius to form a smooth and continuous folding layout, so as to balance and improve the anti-interference performance of the sensing unit against horizontal and vertical strain.

[0037] The thermal conductive layer 11 is made of PDMS / FG thermal conductive composite material, the thermal insulation network 12 and the base layer 4 are both made of PDMS / HGM thermal insulation composite material, and the sensing layer 2 is made of PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material.

[0038] Furthermore, the PDMS / FG thermally conductive composite material mainly consists of PDMS main agent, curing agent, and flake graphite (FG, with a flake diameter of 25-48 μm) in a mass ratio of 10:1:3. The PDMS / HGM thermal insulation composite material mainly consists of PDMS main agent, curing agent, and hollow glass microspheres (HGM, with a particle size of 50-70 μm) in a mass ratio of 10:1:0.75. The PEDOT:PSS / CNT / R-1055 thermosensitive composite material mainly consists of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), carbon nanotubes (CNT, with a diameter of 1-2 nm and a length of 5-30 μm) and tackifier R-1055 in a mass ratio of 1:1:0.01. Both the PDMS main agent and the curing agent are polydimethylsiloxane.

[0039] Furthermore, in the flexible temperature sensor, the contact layer 1 has a thickness of 500 μm excluding the frame, and the thickness of the four edges is 1 mm; the base layer 4 has a thickness of 1 mm excluding the frame, and the thickness of the four edges is 500 μm; the sensing units in the sensing layer 2 are all 8 mm × 8 mm in size and 50 μm in thickness, the serpentine structure of the sensing units has a linewidth of 400 μm, and the lateral and longitudinal spacing between two adjacent sensing units is 16 mm; in the electrode layer 3, the PI substrate 31 of the electrode layer has a thickness of 25 μm, and the Cu electrode pattern 32 has a thickness of 200 nm.

[0040] Specifically, the resistance signal of the sensing unit can reflect temperature information because when the temperature rises, the carrier concentration and mobility of the conductive network in the temperature-sensitive material increase, resulting in a decrease in resistance and exhibiting a negative temperature coefficient of resistance.

[0041] The sensor calibration and testing platform consists of a temperature loading module and a signal measurement module, specifically including a heating platform, a semiconductor water-cooled cooling platform, a DC power supply, a multi-channel temperature sensor, and a digital multimeter. Temperature loading is achieved jointly by the semiconductor cooling platform and the heating platform, with temperature adjustment below room temperature achieved by changing the DC power supply voltage input to the semiconductor cooling platform. Temperature and electrical signals are measured using the multi-channel temperature sensor and the multimeter, respectively.

[0042] The resistance-temperature curve of the prepared temperature-sensitive material is shown in the figure. Figure 2 As shown. PEDOT:PSS was introduced into CNTs, and the resistive response of different PEDOT:PSS / CNT ratios was tested in the range of -30 to 90 °C. Figure 2 (a) It can be seen that when the mass ratio is 1:1, the temperature-sensitive material has a wide range, high sensitivity and high linearity. Figure 2 As shown in (b) of the fitting results, the parameters generally decrease with the addition of PEDOT:PSS, decreasing from 9.32 to 2.64. This indicates that the appropriate addition of PEDOT:PSS can adjust the carrier transport barrier in the CNT conductive network, thereby expanding the measurement range. Excessive PEDOT:PSS will cause the conductivity to stabilize and the measurement range to narrow. Considering all factors, a 1:1 ratio was chosen as the optimal ratio. Subsequently, 1% wt of thickener R-1055 was added based on this ratio to regulate rheology and facilitate preparation. Therefore, the ratio of the temperature-sensitive material PEDOT:PSS / CNT / R-1055 in this invention was determined to be 1:1:0.01.

[0043] The performance test results of the temperature sensing unit are as follows: Figures 3-4 As shown. By Figure 3 As can be seen, the sensing unit has a range of -30 to 90 ℃, a sensitivity (S) of 0.4 % / ℃, and a coefficient of determination of 0.996, indicating high linearity. The sensing unit was fixed below a force-loading platform and repeatedly subjected to impacts of approximately 25 N. Figure 4 (a) indicates that the sensing unit has excellent resistance to pressure interference, and its resistance remains stable throughout the impact process. Figure 4 As shown in (b), the relative resistance change of the sensing unit is extremely small during the bending test, so the bending effect can be ignored. Figure 4 (c) shows the over-range temperature loading test. After the sensing unit was subjected to extreme temperature changes from room temperature to 150 ℃ to -15 ℃, the sensing signal returned to normal and no signal drift occurred. The above test shows that the sensing performance is excellent, with a wide range and high reliability.

[0044] Thermal crosstalk test results of the fabricated flexible temperature sensor are shown below. Figure 5As shown, thermal stimulation was applied to the cells in the second row, first column, and second row, second column of the sensor, with aluminum blocks heated to 90 °C placed on both cells. The results showed that only the two cells subjected to the temperature stimulation exhibited a significant response, with a maximum response time of only 20 s, while the signals of the remaining cells remained stable and almost unaffected. This demonstrates extremely low thermal crosstalk between the sensing cells, thus the sensor exhibits excellent resistance to thermal crosstalk and rapid response.

[0045] This invention also provides a method for fabricating a flexible temperature sensor, which fabricates a fast-response flexible temperature sensor with low thermal crosstalk according to the following steps, such as... Figure 6 As shown: S1. Preparation of materials and molds for each layer: Prepare PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material, PDMS / FG thermally conductive composite material, and PDMS / HGM thermal insulation composite material respectively; use 3D printing technology to print molds that match the structure of each layer and each part in each layer.

[0046] Specifically, step S1 can be divided into the following two steps: S11. Preparation of each layer of materials: Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), carbon nanotubes (CNTs), and tackifier (R-1055) were mixed at a mass ratio of 1:1:0.01 and stirred uniformly at room temperature for 5 min to prepare a PEDOT:PSS / CNT / R-1055 thermosensitive composite material; Polydimethylsiloxane (PDMS main agent and curing agent) and flake carbon powder (FG) were mixed at a mass ratio of 10:1:3 and stirred uniformly at room temperature for 6 min, followed by 30 min of room temperature vacuum degassing treatment to prepare a PDMS / FG thermally conductive composite material; Polydimethylsiloxane (PDMS main agent and curing agent) and hollow glass microspheres (HGM) were mixed at a mass ratio of 10:1:0.75 and stirred uniformly at room temperature for 6 min to prepare a PDMS / HGM thermally insulating composite material; S12. Preparation of various molds: Using photopolymer 3D printing technology, injection molds that match the structure of each layer and each part in each layer are printed. The completed molds are cleaned and a release agent is evenly sprayed on the surface of the molds to facilitate subsequent demolding.

[0047] S2. Preparation of contact layer and base layer: PDMS / HGM thermal insulation composite material is injected into the corresponding molds, and after heating and curing, it is demolded to obtain thermal insulation network 12 and base layer 4; then the thermal insulation network 12 is fixed in a specific mold, and PDMS / FG thermal conductive composite material is injected into the mold, and after heating and curing, it is demolded to obtain contact layer 1.

[0048] Specifically, PDMS / HGM thermal insulation composite material is injected into a mold that matches the thermal insulation network 12 and a mold that matches the base layer 4, respectively. After heating at 120 ℃ for 2 h, the material is cured and demolded to obtain the thermal insulation network 12 and the base layer 4. The thermal insulation network 12 is fixed in a mold that matches the thermal conductive layer 11 using the positioning assembly holes 5. Then, PDMS / FG thermal conductive composite material is injected into a mold that matches the thermal conductive layer 11 and cured and demolded after heating at 120 ℃ for 2 h to obtain the preliminary contact layer. Finally, two positioning mating pillars on the preliminary contact layer are removed to obtain the contact layer 1.

[0049] S3. Preparation of electrode layer: Polyimide coating adhesive is spin-coated on the surface of glass plate substrate and heated to cure, thus preparing electrode layer PI substrate 31. Cu electrode pattern 32 is prepared on electrode layer PI substrate 31 by photolithography and magnetron sputtering processes to obtain electrode layer 3.

[0050] Specifically, the surface of the glass plate substrate is first treated by immersing it in acetone and ethanol solutions for 10 minutes each to remove organic contaminants. Then, a polyimide coating is uniformly spin-coated onto the surface and heated to cure, thus preparing an electrode layer PI substrate 31 with a thickness of 25 μm. A Cu electrode pattern 32 with a thickness of 200 nm is then prepared on the electrode layer PI substrate 31 using photolithography and magnetron sputtering processes to obtain a preliminary electrode layer. Finally, the outline of the preliminary electrode layer is cut using a laser cutter to obtain the electrode layer 3.

[0051] S4. Preparation of the sensing layer: Place the screen printing plate on the electrode layer 3, and use a squeegee to transfer the PEDOT:PSS / CNT / R-1055 thermosensitive composite material to the surface of the electrode layer 3. After heating and curing, the sensing layer 2 is obtained.

[0052] Specifically, the screen printing plate is aligned with the electrode layer 3 and placed on top. The screen printing process is used, and the PEDOT:PSS / CNT / R-1055 thermosensitive composite material is scraped into the gaps of the screen printing plate and transferred to the surface of the electrode layer 3 using a squeegee. After heating at 120 °C for 1 h, it is cured to obtain the sensing layer 2 connected to the Cu electrode pattern 32. S5. Sensor Assembly: After processing, the prepared layers are aligned and stacked sequentially, and then bonded under certain conditions to prepare a flexible temperature sensor.

[0053] Specifically, the connecting surfaces of each layer are plasma-treated, and then the treated layers are aligned, stacked and assembled, and then heated and bonded at 120 °C for 30 min to prepare a flexible temperature sensor.

[0054] In specific implementation, the manufacturing process of the sensor of the present invention mainly includes the manufacturing and overall stacking assembly of each layer, namely the contact layer 1, the sensing layer 2, the electrode layer 3, and the base layer 4. Figure 6 The flowchart shows the following steps: Step 1: Prepare the materials for each layer: Weigh the corresponding raw materials of PEDOT:PSS / CNT / R-1055 thermosensitive composite material at a mass ratio of 1:1:0.01 and mix them uniformly at room temperature using a planetary mixer for 5 minutes. Weigh the corresponding raw materials of PDMS / FG thermally conductive composite material and PDMS / HGM thermal insulation composite material at mass ratios of 10:1:3 and 10:1:0.75 respectively, and mix them uniformly at room temperature using a planetary mixer for 6 minutes. For the PDMS / FG thermal insulation composite material, it is necessary to additionally place it in a vacuum drying oven for 30 minutes for room temperature vacuum degassing. Step 2, Prepare the mold: such as Figures 7-8 As shown, photopolymer 3D printing technology was used to print injection molds that matched the parts of the contact layer 1 and the base layer 4, respectively. The contact layer required two molds, one for the thermal insulation network 12 and the other for the thermally conductive layer 11. The completed molds were ultrasonically cleaned in anhydrous ethanol for 30 minutes. After removal, residual ethanol and dust on the mold surface were removed using a high-pressure air canister. Then, a release agent was evenly sprayed onto the mold surface to facilitate the subsequent peeling of the sensor components.

[0055] Step 3, Prepare the contact layer: such as Figures 7-8 As shown, the configured PDMS / HGM thermal insulation composite material is injected into a 3D printing mold that matches the prepared thermal insulation network 12. The entire assembly is heated at 120 ℃ for 2 h to cure and form. The prepared thermal insulation network 12 is then demolded from the mold. The thermal insulation network 12 is fixed to the mold corresponding to the thermal conductive layer 11 using the positioning and assembly holes 5 of the mold. Subsequently, the configured PDMS / FG thermal conductive composite material is injected into the mold and heated at 120 ℃ for 2 h to cure and form. Finally, the contact layer 1 is demolded from the mold and two positioning mating pillars are removed.

[0056] Step 4: Prepare the base layer: Inject the prepared PDMS / HGM thermal insulation composite material into the 3D printing mold that matches the base layer 4. Heat the whole at 120 ℃ for 2 h to solidify and shape it. Demold the prepared base layer 4 from the mold.

[0057] Step 5: Electrode Layer Preparation: The glass substrate was ultrasonically cleaned in acetone and ethanol for 10 min each to remove contaminants and then dried with nitrogen. Polyimide coating adhesive was uniformly spin-coated onto the glass substrate at 1200 r / min to prepare a 25 μm thick film. A pre-baking method was used, gradually transitioning from a low temperature of 50 °C to a high temperature of 120 °C to remove solvent from the film. The film was then placed in a nitrogen oven and gradually heated from room temperature to 300 °C to prepare the PI electrode layer 31. After cooling, photoresist was spin-coated onto the surface of the PI electrode layer 31. Then, the mask pattern of the Cu electrode pattern 32 was transferred onto the photoresist using photolithography. Subsequently, Cr and Cu were sequentially deposited onto the PI electrode layer 31 using magnetron sputtering, controlling the sputtering time to achieve a Cr layer thickness of 50 nm and a Cu layer thickness of 200 nm. The photoresist was then washed away, and the outline shape of the electrode layer 3 was cut using a laser cutter.

[0058] Step 6, Fabrication of the sensing layer: The mask pattern of sensing layer 2 is as follows Figure 9 As shown, the mask pattern is placed on the upper surface of electrode layer 3 and aligned using screen printing technology. The uncured temperature-sensitive composite material is then scraped into the gaps of the screen printing plate. After completion, the screen printing plate is removed, and the sensing layer is heated at 120 °C for 1 h to fully cure.

[0059] Step 7: Perform plasma activation treatment on the connection surfaces between contact layer 1, sensing layer 2, electrode layer 3 and base layer 4, then align each layer and apply PDMS adhesive. After stacking and assembling, heat and bond at 120 °C for 30 min to achieve reliable assembly and complete the manufacturing of the flexible temperature sensor.

[0060] Step 8: Use a heating platform and a semiconductor water-cooling platform as heat sources to perform subsequent calibration and testing on the flexible temperature sensor.

[0061] The specific embodiments described above are for illustrative purposes only and are not intended to limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made to the invention within the spirit and scope of the claims shall fall within the protection scope of the invention.

Claims

1. A fast-response flexible temperature sensor with low thermal crosstalk, characterized in that: The device comprises a contact layer (1), a sensing layer (2), an electrode layer (3), and a base layer (4) stacked sequentially. The contact layer (1) and the base layer (4) are upper and lower encapsulation layers. The contact layer (1) is in contact with the object being measured. The contact layer (1) includes a thermally conductive layer (11) and a thermal insulation network (12). The base layer (4) is in contact with the loading surface. The lower part of the thermally conductive layer (11) is in contact with the upper part of the sensing layer (2). The thermal insulation network (12) is embedded in the contact layer (1), and the outline of the thermal insulation network (12) is connected to the outline of the thermally conductive layer (11). The contact layer (1) and the base layer (4) are designed with a concave-convex interlocking snap-fit ​​structure; the sensing layer (2) includes multiple sensing units arranged in an array; the electrode layer (3) includes an electrode layer PI substrate (31) and a Cu electrode pattern (32); the upper surface of the electrode layer PI substrate (31) is aligned and connected with the inner surface of the groove of the contact layer (1), and the lower surface of the electrode layer PI substrate (31) is aligned and connected with the upper surface of the protrusion of the base layer (4); the electrode layer PI substrate (31) is provided with a Cu electrode pattern (32), and each sensing unit is connected to the Cu electrode pattern (32) and outputs a resistance signal; The upper part of the sensing unit is connected to the thermally conductive layer (11), and the base layer (4) is arranged below the sensing unit. The sensing unit, the thermally conductive layer (11) and the base layer (4) together constitute a thermally conductive and thermally insulating synergistic structure. The thermally conductive and thermally insulating synergistic structure can enhance the rapid response of the sensing unit. The thermal insulation network (12) is embedded in the contact layer (1) to limit the heat conduction between the thermally conductive layer (11) and the sensing unit to the area corresponding to a single sensing unit, so as to reduce the lateral thermal crosstalk between adjacent sensing units. The heat insulation network (12) includes multiple transverse heat insulation strips and multiple longitudinal heat insulation strips. In the sensing unit array, a transverse heat insulation strip is provided between each two adjacent rows of sensing units, and a longitudinal heat insulation strip is provided between each two adjacent columns of sensing units. The multiple transverse heat insulation strips and the multiple longitudinal heat insulation strips together form a grid structure. The thermal conductive layer (11) is made of PDMS / FG thermal conductive composite material, the thermal insulation network (12) and the base layer (4) are both made of PDMS / HGM thermal insulation composite material, and the sensing layer (2) is made of PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material. The PDMS / FG thermally conductive composite material is composed of PDMS main agent, curing agent and flake carbon powder in a mass ratio of 10:1:

3. The PDMS / HGM thermal insulation composite material is composed of PDMS main agent, curing agent and hollow glass microspheres in a mass ratio of 10:1:0.

75. The PEDOT:PSS / CNT / R-1055 thermosensitive composite material is composed of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, carbon nanotubes and tackifier R-1055 in a mass ratio of 1:1:0.

01. Both the PDMS main agent and the curing agent are polydimethylsiloxane.

2. The fast-response flexible temperature sensor with low thermal crosstalk according to claim 1, characterized in that: Each of the aforementioned sensing units is a serpentine structure. The serpentine structure adopts a bidirectional expansion design based on an S-shape, with two S-shaped tracks spaced apart in the horizontal and vertical directions respectively. The tracks are connected by circular arcs of the same radius to form a smooth and continuous folding layout.

3. A method for fabricating a fast-response flexible temperature sensor with low thermal crosstalk as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. Preparation of materials and molds for each layer: Prepare PEDOT:PSS / CNT / R-1055 temperature-sensitive composite material, PDMS / FG thermally conductive composite material, and PDMS / HGM thermal insulation composite material respectively; use 3D printing technology to print molds that match the structure of each layer and each part in each layer; S2. Preparation of contact layer and base layer: PDMS / HGM thermal insulation composite material is injected into the corresponding molds respectively, and after heating and curing, it is demolded to obtain thermal insulation network (12) and base layer (4); the thermal insulation network (12) is fixed in the corresponding mold, and then PDMS / FG thermal conductive composite material is injected into the mold, and after heating and curing, it is demolded to obtain contact layer (1). S3. Preparation of electrode layer: spin-coating polyimide coating adhesive on the surface of glass plate substrate and heat curing to prepare electrode layer PI substrate (31). Then, Cu electrode pattern (32) is prepared on electrode layer PI substrate (31) by photolithography and magnetron sputtering process to obtain electrode layer (3). S4. Preparation of the sensing layer: Place the screen printing plate on the electrode layer (3), and use a squeegee to transfer the PEDOT:PSS / CNT / R-1055 thermosensitive composite material to the surface of the electrode layer (3). After heating and curing, a sensing layer (2) connected to the Cu electrode pattern (32) is obtained. S5. Sensor Assembly: After processing, the prepared layers are aligned and stacked sequentially, and then bonded under certain conditions to prepare a flexible temperature sensor.

4. The preparation method according to claim 3, characterized in that, Step S1 specifically involves: S11. Preparation of each layer of materials: PEDOT:PSS / CNT / R-1055 thermosensitive composite material was prepared by mixing poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, carbon nanotubes and tackifier R-1055 at a mass ratio of 1:1:0.01 and stirring at room temperature for 5 min; PDMS / FG thermally conductive composite material was prepared by mixing polydimethylsiloxane and flake carbon powder at a mass ratio of 10:1:3 and stirring at room temperature for 6 min, followed by 30 min of room temperature vacuum degassing treatment; PDMS / HGM thermal insulation composite material was prepared by mixing polydimethylsiloxane and hollow glass microspheres at a mass ratio of 10:1:0.75 and stirring at room temperature for 6 min. S12. Preparation of various molds: Using photopolymer 3D printing technology, molds that match the structure of each layer and each part in each layer are printed, and each mold is cleaned and a release agent is sprayed on the surface of the mold.

5. The preparation method according to claim 3, characterized in that, Steps S2-S5 are specifically as follows: S2. Preparation of contact layer and base layer: PDMS / HGM thermal insulation composite material is injected into the mold matching the thermal insulation network (12) and the mold matching the base layer (4), respectively. After heating at 120 °C for 2 h, it is cured and demolded to obtain the thermal insulation network (12) and the base layer (4). The thermal insulation network (12) is fixed in the mold matching the thermal conductive layer (11) by means of the positioning assembly hole (5). Then, PDMS / FG thermal conductive composite material is injected into the mold matching the thermal conductive layer (11). After heating at 120 °C for 2 h, it is cured and demolded to obtain the preliminary contact layer. Then, the two positioning mating pillars on the preliminary contact layer are removed to obtain the contact layer (1). S3. Preparation of electrode layer: First, the surface of the glass plate substrate is treated by immersing it in acetone and ethanol solutions for ultrasonic cleaning for 10 minutes each to remove organic contaminants. Then, polyimide coating adhesive is spin-coated on its surface and heated to cure, thus preparing the electrode layer PI substrate (31). Cu electrode pattern (32) is prepared on the electrode layer PI substrate (31) by photolithography and magnetron sputtering processes to obtain the preliminary electrode layer. The outline shape of the preliminary electrode layer is then cut using a laser cutter to obtain the electrode layer (3). S4. Preparation of the sensing layer: Place the screen printing plate on the electrode layer (3), and use the screen printing process to scrape the PEDOT:PSS / CNT / R-1055 thermosensitive composite material into the gap of the screen printing plate and transfer it to the surface of the electrode layer (3). After heating at 120 °C for 1 h, it is cured to obtain the sensing layer (2) connected to the Cu electrode pattern (32). S5. Sensor Assembly: The surfaces of each layer are subjected to plasma treatment. Then, the treated layers are aligned, stacked and assembled, and then heated and bonded at 120 °C for 30 min to prepare a flexible temperature sensor.

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