Bionic self-adaptive thermoelectric device and preparation method thereof

Abstract

The invention discloses a bionic self-adaptive thermoelectric device and a preparation method thereof. The bionic self-adaptive thermoelectric device comprises a sensor film, a conductive electrode and a substrate, the sensor film comprises an actuating layer and a sensing layer which are sequentially arranged, the actuating layer comprises a polydimethylsiloxane layer and a polyimide layer, and the polyimide layer is close to one side of the sensing layer; the sensing layer comprises tellurium nanowires, a conductive polymer and bacterial cellulose, and the conductive electrode is stretchable silver paste; the substrate is PDMS engraved with a groove, a liquid metal circuit is arranged on the surface of the groove, the sensor film is inserted into the groove to enable the sensing layer to be completely attached to the liquid metal circuit, and a PDMS packaging layer is arranged on the surface of the liquid metal circuit. The bionic adaptive thermoelectric device is constructed based on a three-dimensional structure and a hierarchical conductive network, and has excellent temperature sensitivity, pressure resolution and cycling stability.

Description

Technical Field

[0001] This application relates to the field of thermoelectric device technology, and in particular to a biomimetic adaptive thermoelectric device and its fabrication method. Background Technology

[0002] In nature, the closed-loop sensing-motion reflex of sea anemones and the touch-responsive behavior of mimosa plants, among other "sensor-actuator integrated" biological systems, have provided design inspiration for intelligent electronic devices. With the development of the Internet of Things, metaverse, and wearable medical technologies, there is an urgent need for miniaturized, flexible, and multifunctional devices with both high-sensitivity sensing and autonomous response capabilities in fields such as human-computer interaction and remote monitoring.

[0003] Thermoelectric materials based on the Seebeck effect can directly convert temperature gradients into electrical signals and possess advantages such as flexibility and portability, making them a research hotspot in the field of flexible electronics. In existing technologies, hybrid systems achieve power factor optimization through carrier filtering effects, improving power generation efficiency while maintaining a stable Seebeck coefficient.

[0004] However, these devices have obvious drawbacks: First, most of them cannot achieve both high Seebeck coefficient and high conductivity, limiting temperature sensing sensitivity. Some have high temperature resolution but cannot detect other physical parameters such as pressure and wind speed. Second, there is a common bottleneck in the "sensor-actuator separation" design, where sensors and actuators need to be integrated separately, which increases structural complexity and manufacturing costs, and also causes problems such as feedback delay and poor interface compatibility, making it impossible to achieve real-time closed-loop response like a biological system.

[0005] In the field of multifunctional sensing, existing wearable electronic devices mostly rely on the integration of multiple single-function sensors to achieve multi-parameter detection. For example, some devices combine triboelectric and piezoresistive sensing mechanisms to simulate human skin receptors (Adv. Mater., 2023, 35, 2300593), but this requires the design of complex double-layer structures. Other studies have introduced materials with near-zero thermal expansion coefficients (Adv. Mater., 2024, 36, 2407859) to avoid temperature interference with pressure sensing, but this further increases the difficulty of fabrication. More importantly, these integrated devices are prone to "signal coupling" problems—different stimuli (such as temperature and pressure) may produce similar electrical signal outputs, leading to difficulties in signal decoupling and inaccurate differentiation of the detected object. Furthermore, the mechanical stability of existing flexible electronic devices is generally insufficient; most devices exhibit significant performance degradation after thousands of cycles, making it difficult to meet long-term usage requirements. Simultaneously, the lack of self-protection mechanisms against extreme environments (such as high temperatures and strong airflows) limits their application in scenarios such as industrial safety early warning and outdoor monitoring.

[0006] From a materials design perspective, traditional thermoelectric materials often employ single inorganic or organic systems, making it difficult to simultaneously meet the requirements for sensing sensitivity, mechanical flexibility, and environmental tolerance. For example, while pure inorganic nanowire films possess high thermoelectric performance, they are brittle and prone to breakage; pure organic polymer films exhibit excellent flexibility, but suffer from low conductivity and slow sensing response. Although some studies have introduced composite systems, poor adhesion to the substrate leads to problems such as interface delamination and disruption of conductive pathways under stress. Furthermore, existing encapsulation materials mostly provide only physical protection and do not endow devices with additional functions (such as thermal management and improved environmental adaptability), further limiting the overall performance of the devices.

[0007] In summary, the current field of thermoelectric devices faces three major challenges: First, the integration of "sensing-drive integration" is difficult and cannot achieve real-time closed-loop response; second, signals are easily coupled when sensing multiple parameters, which limits the detection accuracy; and third, mechanical stability and environmental tolerance are insufficient, and self-protection capabilities are lacking.

[0008] Therefore, developing a biomimetic adaptive thermoelectric device that draws on the characteristics of biological systems integration, combines multimodal high-sensitivity sensing and autonomous thermal drive functions, and possesses excellent stability is key to solving the above problems and is of great significance to promoting the development of intelligent electronic technology. Summary of the Invention

[0009] In view of this, this application provides a biomimetic adaptive thermoelectric device inspired by the interaction between sensory cells and muscle cells in sea anemones. Its internal dynamic hydrogen bond network can enhance stress dissipation and interfacial adhesion, and it not only has excellent temperature sensitivity and pressure resolution, but also thermal adaptability.

[0010] This application provides a biomimetic adaptive thermoelectric device, including a sensor thin film, conductive electrodes, and a substrate;

[0011] The sensor film includes an actuation layer and a sensing layer arranged sequentially. The actuation layer includes a polydimethylsiloxane (PDMS) layer and a polyimide (PI) layer, with the PI layer located closer to the sensing layer. The sensing layer includes a sensing unit and a conductive electrode. The sensing unit includes tellurium nanowires (Te NWs), a conductive polymer (PEDOT:PSS), and bacterial cellulose (BC). The conductive electrode is a stretchable silver paste. The substrate is a PDMS with grooves. A liquid metal circuit is provided on the surface of the grooves. The sensor film is inserted into the grooves so that the sensing layer and the liquid metal circuit are completely bonded. A PDMS encapsulation layer is provided on the surface of the liquid metal circuit.

[0012] The described biomimetic adaptive thermoelectric device achieves seamless integration of multimodal sensing and thermal self-driving, solving the problems of existing electronic devices such as separation of sensing and driving, complex integration, limited response capability, and insufficient stability. It also possesses excellent environmental adaptability and controllability. In some specific implementations, the liquid metal in the liquid metal circuit includes one or more of gallium, indium, or tin, and the mass ratio of gallium, indium, and tin is (65-70):(20-25):10.

[0013] In some specific implementations, the conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS).

[0014] In some specific implementations, the temperature detection range of the sensing layer is -120 ℃ to 150 ℃, the temperature sensitivity is 0.2 ℃, and the pressure resolution is 0.03 mm.

[0015] In some specific implementations, the sensor film is positioned at an angle of 55° to 60° to the substrate.

[0016] In some specific implementations, the length of the sensor film is 7 mm to 9 mm, and the width of the sensor film is 2 mm to 4 mm.

[0017] This application provides a method for fabricating a biomimetic adaptive thermoelectric device, comprising:

[0018] A PDMS layer and a sensing layer are formed on both sides of the PI film to obtain a sensor film. A stretchable silver paste is set on the surface of the sensor film as a conductive electrode.

[0019] A groove is provided on the substrate surface, and a liquid metal circuit is formed on the surface of the groove. The sensor film is inserted into the groove so that the conductive electrode is completely attached to the liquid metal circuit. A PDMS encapsulation layer is formed on the surface of the liquid metal circuit to obtain a biomimetic adaptive thermoelectric device.

[0020] In some specific implementations, forming the PDMS layer includes spin-coating a mixture of PDMS main agent and curing agent onto the surface of a PI film and curing it to form a PDMS layer. The curing time is 5 h to 6 h and the curing temperature is 50 ℃ to 70 ℃.

[0021] In some specific implementations, the thickness of the PI film is 15 μm to 60 μm, and the thickness of the PDMS layer is 140 μm to 290 μm.

[0022] In some specific implementations, the mass ratio of the PDMS main agent to the curing agent is (9-12):1, and the curing agent is SYLGARD 184 part B.

[0023] Inspired by the interaction between sensory and muscle cells in sea anemones, the biomimetic adaptive thermoelectric device described in this application is constructed based on a three-dimensional structure and a hierarchical conductive network. Its internal dynamic hydrogen bond network enhances stress dissipation and interfacial adhesion, exhibiting not only excellent temperature sensitivity (0.2 °C) and pressure resolution (0.03 mm), but also thermal adaptability. It can actively trigger a protection mechanism through thermal response deformation to avoid high-temperature stimulation, and its drive threshold is adjustable, maintaining excellent mechanical stability even after 140,000 cycles. This application solves the problems of complex integration and limited response capabilities caused by the separation of sensing and actuation in existing electronic devices. Its ingenious structural design and strong practicality make it promising for applications in intelligent electronics fields such as human-computer interaction, monitoring systems, and robotics. Attached Figure Description

[0024] Figure 1 This is a TEM image of the Te NWs provided in Embodiment 1 of this application;

[0025] Figure 2 This is a SEM image of the Te NWs / PEDOT:PSS / BC composite material provided in Example 1 of this application;

[0026] Figure 3 This is a schematic diagram of the thermoelectric device provided in Embodiment 1 of this application;

[0027] Figure 4 This is a physical diagram of the thermoelectric device provided in Embodiment 1 of this application;

[0028] Figure 5 This is a graph showing the voltage variation with temperature of the biomimetic adaptive thermoelectric device prepared in Example 1 of this application;

[0029] Figure 6 Temperature cycling test diagram of the biomimetic adaptive thermoelectric device prepared in Example 1 of this application at -55 ℃ and 60 ℃;

[0030] Figure 7 The curves showing the driving temperature of the biomimetic adaptive thermoelectric device provided in this application vary with the thickness of the PDMS layer and the PI layer, respectively. The left side represents the PDMS layer, and the right side represents the PI layer.

[0031] Figure 8 The stability test diagram of the biomimetic adaptive thermoelectric device prepared in Example 1 of this application after 140,000 loading / unloading cycles;

[0032] Figure 9 The simulated thermal deformation of the biomimetic adaptive thermoelectric device prepared in Example 1 at a heat source temperature of 120 °C and wind speeds of 1.5 and 10 m / s. Detailed Implementation

[0033] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0034] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0035] It should be understood that the order of steps or the sequence of actions is not important as long as this application remains operational. Furthermore, two or more steps or actions may be performed simultaneously.

[0036] The use of any and all instances or exemplary language such as “e.g.” or “include” in this document is intended merely to better illustrate the application and does not constitute a limitation on the scope of the application. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of this application.

[0037] Furthermore, the numerical ranges and parameters used to define this application are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise explicitly stated, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0038] This application provides a biomimetic adaptive thermoelectric device, including a sensor thin film, conductive electrodes, and a substrate;

[0039] The sensor film includes an actuation layer and a sensing layer arranged sequentially. The actuation layer includes a PDMS layer and a PI layer, with the PI layer closer to the sensing layer. The sensing layer includes Te NWs, a conductive polymer, and BC. The conductive electrode is a stretchable silver paste. The sensing layer is located on the left side of the PI layer surface, and the stretchable silver paste is located on the right side of the PI layer surface. The substrate is a PDMS with grooves. A liquid metal circuit is provided on the surface of the grooves. The sensor film is inserted into the grooves so that the sensing layer and the liquid metal circuit are completely bonded. A PDMS encapsulation layer is provided on the surface of the liquid metal circuit.

[0040] The biomimetic adaptive thermoelectric device provided in this application has the core advantage of borrowing the "sensory-motor" synergistic mechanism of sea anemones to achieve seamless integration of multimodal sensing and thermal self-driving: the hierarchical conductive network of the sensing layer ensures high-sensitivity detection (temperature sensitivity 0.2 ℃, pressure resolution 0.03 mm), and the dynamic hydrogen bond network provides excellent mechanical stability for 140,000 cycles; the thermal driving part achieves high-temperature protection with adjustable threshold through the thermal expansion difference of the double-layer structure. The fabrication method adopts mature processes such as drop casting, spin coating, and screen printing, which are cost-controllable and easy to mass-produce. It can be widely used in fields such as human-computer interaction, environmental monitoring, medical health, and industrial safety early warning, providing a new direction for the integrated and multifunctional development of intelligent electronic devices.

[0041] In some specific implementations, the sensing layer is composed of Te NWs, PEDOT:PSS, and BC, forming a hierarchical conductive network and a dynamic hydrogen bond network. In some specific implementations, the temperature detection range of the sensing layer is -120℃ to 150℃, specifically -120℃, -100℃, -80℃, -50℃, -30℃, -10℃, 0℃, 10℃, 20℃, 50℃, 80℃, 100℃, 120℃, 140℃, and 150℃, with a temperature sensitivity of 0.2℃ and a pressure resolution of 0.03 mm. The actuation layer comprises a PDMS layer and a PI layer, which have different coefficients of thermal expansion. The thickness of the PI layer is 15 μm to 60 μm, and can be 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 55 μm, or 60 μm. The thickness of the PDMS layer is 140 μm to 290 μm, and can be 140 μm, 150 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 250 μm, 260 μm, 280 μm, or 290 μm. The thickness ratio of the PDMS layer to the PI layer is adjustable to control the thermally driven threshold temperature, which can be controlled within the range of 50~120 °C to adapt to the high-temperature protection requirements of different scenarios. In some specific implementations, the Te NWs are synthesized by a hydrothermal method, with a diameter of approximately 22 nm, high crystallinity, and no impurities. The preparation method of the Te NWs includes:

[0042] Polyvinylpyrrolidone (PVPK30) and tellurium dioxide (TeO2) were dissolved in ammonia (NH3·H2O) and deionized water (18.2 megohms·cm). Hydrazine hydrate (N2H4·H2O) was added under vigorous stirring to ensure homogeneous mixing. The mixture was then placed in an oven for reaction. After the reaction was complete, the oven was closed, and the autoclave was allowed to cool naturally to room temperature to obtain a Te NWs solution. In some specific implementations, the reaction temperature was 160 °C to 190 °C, preferably 180 °C, and the reaction time was 7 h to 9 h, preferably 8 h. The morphology of the Te NWs was observed using a transmission electron microscope (TEM, Hitachi H-7650, accelerating voltage 100 kV), showing that they had a uniform diameter of approximately 22 nm and no obvious agglomeration.

[0043] In some specific implementations, the liquid metal in the liquid metal circuit includes one or more of gallium, indium, or tin, and the mass ratio of gallium, indium, and tin is (65-70):(20-25):10.

[0044] In some specific implementations, the conductive polymer is PEDOT:PSS; the dynamic hydrogen bond network between molecules of BC in the sensing layer can enhance stress dissipation and interfacial adhesion, suppress shrinkage cracks during film formation, and improve film uniformity.

[0045] In some specific implementations, the sensor film is positioned at an angle of 55° to 60° to the substrate, preferably 57.5°, and the conductive electrode is disposed on the surface of the sensing layer, in contact with the liquid metal. In some specific implementations, the length of the sensor film is 7 mm to 9 mm, which can be 7.5 mm, 8 mm, 8.5 mm, or 9 mm, and the width of the sensor film is 2 mm to 4 mm, which can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, or 4 mm.

[0046] This application provides a method for fabricating a biomimetic adaptive thermoelectric device, comprising:

[0047] A PDMS layer and a sensing layer are formed on both sides of the PI film to obtain a sensor film. A stretchable silver paste is set on the surface of the sensor film as a conductive electrode.

[0048] A groove is provided on the substrate surface, and a liquid metal circuit is formed on the surface of the groove. The sensor film is inserted into the groove so that the conductive electrode is completely attached to the liquid metal. A PDMS encapsulation layer is formed on the surface of the liquid metal circuit to obtain a biomimetic adaptive thermoelectric device.

[0049] This application first mixes Te NWs, PEDOT:PSS, and BC, and then drop-casts the mixture onto a PI film using a mask. Next, a mixture of PDMS main agent and curing agent (10:1) is spin-coated onto the surface of the PI film, cured to form a PDMS layer, and mechanically cut to obtain the sensor film. In some specific implementations, the curing time is 5 to 6 hours, preferably 6 hours, and the curing temperature is 50°C to 70°C, preferably 60°C. The PDMS of the encapsulation layer is prepared by mixing the main agent and curing agent in a specific ratio and then curing. In some specific implementations, the thickness of the PI film is from 15 μm to 60 μm, and can be 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 55 μm, or 60 μm. The thickness of the PDMS layer is from 140 μm to 290 μm, and can be 140 μm, 150 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 250 μm, 260 μm, 280 μm, or 290 μm. In some specific implementations, the mass ratio of the PDMS main agent to the curing agent is (9-12):1, and the curing agent is SYLGARD 184 part B.

[0050] This application then fabricates grooves on a PDMS substrate, forms a liquid metal circuit through screen printing, and encapsulates it with PDMS; stretchable silver paste is used as a connecting electrode and disposed on the surface of the sensor film. The sensor film is then inserted into the grooves to obtain a biomimetic adaptive thermoelectric device. In some specific implementations, the angle at which the sensor film is inserted into the groove is 55° to 60°, preferably 57.5°.

[0051] The biomimetic adaptive thermoelectric device has a temperature detection range of -120 ℃ to 150 ℃, a temperature sensitivity of 0.2 ℃, a pressure resolution of 0.03 mm, and exhibits weak sensing performance degradation during 140,000 loading / unloading cycles with a displacement amplitude of 4 mm and a period of 3 seconds.

[0052] In some specific implementations, the biomimetic adaptive thermoelectric device provided in this application can be used in temperature sensing, pressure sensing, wind speed detection, respiratory monitoring or high temperature early warning systems. Specifically, it is suitable for multi-parameter sensing and intelligent response in scenarios such as human-computer interaction, environmental monitoring, medical health, and industrial safety early warning. It can realize multi-modal detection of temperature, pressure, wind speed, respiratory signals and other functions as well as high temperature self-protection function.

[0053] This application is the first to draw on the "sensory-motor" synergistic mechanism of sea anemones to achieve seamless integration of multimodal sensing (temperature, pressure, wind speed, respiratory signal) and thermal self-drive, without the need for additional integrated sensors and actuators. It solves the problems of integration complexity and feedback delay caused by the "sensor-drive separation" of traditional devices, and can realize closed-loop sensory-motor reflection.

[0054] It boasts excellent sensing performance and signal decoupling, with a temperature detection range covering -120 ℃ to 150 ℃, a temperature sensitivity of 0.2℃, and a pressure resolution of 0.03 mm. Through a dual signal output mechanism of "voltage-temperature" and "resistance-pressure", it effectively avoids signal coupling between different stimuli and can distinguish between different environmental parameters such as temperature and pressure.

[0055] With strong mechanical stability and environmental tolerance, the dynamic hydrogen bond network of bacterial cellulose can enhance stress dissipation and interfacial adhesion. After 140,000 loading / unloading cycles, the sensing performance of the device has a weak decay, which is better than most existing flexible devices.

[0056] With adjustable thermal adaptability, the thermal drive threshold temperature can be controlled within the range of 50~120 ℃ by adjusting the thickness ratio of the PDMS layer to the PI layer, adapting to the high temperature protection needs of different scenarios, such as overheat protection of electronic equipment and fire warning. Moreover, it can be reset and reused after the temperature recovers, which is more economical than traditional disposable fuses.

[0057] The preparation process is simple and cost-controllable, using mature processes such as drop casting, spin coating, and screen printing, without the need for complex and precision equipment, and with low operation difficulty; the raw materials (such as BC, Te NWs) are widely available and easy to industrialize.

[0058] With a wide range of applications, it can be used in temperature sensors (medical surface monitoring, industrial equipment temperature measurement), pressure sensors (robot tactile feedback), wind speed sensors (environmental monitoring, disaster early warning), respiratory monitoring equipment (medical health) and high temperature early warning systems (circuit protection, fire alarm), providing key technical support for fields such as smart electronics, wearable devices, and industrial safety.

[0059] The present application is further illustrated below with reference to embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0060] Example 1

[0061] This embodiment provides a biomimetic adaptive thermoelectric device, the fabrication method of which includes:

[0062] Synthesis of Te NWs: At room temperature, 10 mL of 25% ammonia water (NH3·H2O) and 63 mL of deionized water (18.2 megohms·cm) were added to a 100 mL polytetrafluoroethylene (PTFE)-lined autoclave, and 5 g of polyvinylpyrrolidone (PVP K30) and 0.654 g of tellurium dioxide (TeO2) were dissolved. 2 mL of 85% hydrazine hydrate (N2H4·H2O) was added under vigorous stirring, and stirring was continued for 10 minutes to ensure uniform mixing. The autoclave was sealed and placed in an oven at 180 °C for 8 hours. After the reaction was completed, the oven was turned off, and the autoclave was allowed to cool naturally to room temperature to obtain the Te NWs solution.

[0063] The morphology of Te NWs was observed by transmission electron microscopy (TEM, Hitachi H-7650, accelerating voltage 100 kV). The results showed that the diameter was uniform, about 22 nm, and there was no obvious aggregation.

[0064] Figure 1 This is a TEM image of the Te NWs provided in Embodiment 1 of this application;

[0065] Preparation of Te NWs / PEDOT:PSS / BC composite material: 5 mL of Te NWs stock solution was measured and centrifuged at 8000 rpm for 3 min. The precipitate was taken and 1 mL of deionized water was added. The mixture was shaken to disperse it completely. Then, 100 μL of PEDOT:PSS and 50 μL of BC were added and mixed thoroughly to obtain a uniform composite material.

[0066] Figure 2 This is a SEM image of the Te NWs / PEDOT:PSS / BC composite material provided in Example 1 of this application;

[0067] Preparation of composite films: A PI film with a thickness of 50 μm was selected as a flexible substrate and placed in a plasma cleaner for 3-5 minutes to improve the hydrophilicity of the substrate surface. A mask was placed on the surface of the treated PI substrate, and the prepared composite material was slowly dripped onto the cutout area of ​​the mask using a micropipette. The PDMS main agent and SYLGARD 184part B curing agent were mixed evenly at a ratio of 10:1 (weight percentage) and spin-coated onto the substrate surface with the dispersion at a speed of 200 rpm for 30 seconds to form a PDMS coating with a thickness of approximately 215 μm. The composite film was cured on a 60 ℃ heating stage for 6 hours. After cooling to room temperature, it was mechanically cut into individual sensor films with a length of 8 mm and a width of 3 mm.

[0068] Electrode and circuit fabrication: Stretchable silver paste was uniformly coated onto the mask spacing of the single sensor film obtained in the previous step using a micropipette. The film coated with stretchable silver paste was then placed on a 60 °C heating stage and cured for 30 minutes to form conductive electrodes. Grooves were fabricated on the PDMS substrate using a laser cutting system (Delphilaser UP-D). Specific circuits were formed on the PDMS substrate using liquid metal (gallium:indium:tin = 68.5:21.5:10, mass ratio) through screen printing, ensuring close contact between the liquid metal and the sensor film.

[0069] Device assembly and packaging: The sensor film with stretchable silver paste electrodes obtained in the previous step is inserted into the groove of the PDMS substrate at an angle of 57.5°. The position of the film is adjusted by an optical microscope to ensure that the electrodes are completely attached to the liquid metal circuit. The remaining PDMS mixture (PDMS main agent: curing agent = 10:1) is uniformly poured onto the groove and the surface of the sensor film to fix the sensor film. The assembled device is placed on a 60 ℃ heating stage for curing, and finally a biomimetic adaptive thermoelectric device is obtained.

[0070] Figure 3 This is a schematic diagram of the thermoelectric device provided in Embodiment 1 of this application, wherein the left figure is an overall schematic diagram and the right figure is a schematic diagram of the surface of the sensor film, including the sensor film, the conductive electrode 2 and the substrate 3;

[0071] The sensor film includes an actuation layer and a sensing layer arranged sequentially. The actuation layer includes a polydimethylsiloxane layer 11 and a polyimide layer 12, with the polyimide layer 12 located near the sensing layer. The sensing layer 4 includes tellurium nanowires, a conductive polymer, and bacterial cellulose. The conductive electrode 2 is a stretchable silver paste. The substrate 3 is a PDMS with grooves. A liquid metal circuit 5 is provided on the surface of the grooves. The sensor film 1 is inserted into the grooves so that the sensing layer and the liquid metal circuit 5 are completely adhered. A PDMS encapsulation layer is provided on the surface of the liquid metal circuit 5. The liquid metal circuit is connected to a copper wire 51.

[0072] Figure 4 This is a physical diagram of the thermoelectric device provided in Embodiment 1 of this application.

[0073] Example 2

[0074] This embodiment provides a biomimetic adaptive thermoelectric device, which differs from Embodiment 1 only in that the PDMS layer thickness is 255 µm and the PI layer thickness is 50 µm. The remaining steps are the same as in Embodiment 1, verifying the feasibility of controlling the driving threshold by adjusting the thickness ratio of the bilayer film.

[0075] This thermoelectric device can achieve self-powered detection of target temperature and thermal proximity, and it has thermally driven characteristics, enabling it to actively avoid high-temperature objects. The temperature of the biomimetic adaptive thermoelectric device prepared in Example 1 was controlled using liquid nitrogen and a heating stage. The output voltage was recorded using a data acquisition multimeter (Keithley DMM7510). The results show that there is a good linear relationship between temperature and voltage in the range of -120 ℃ to 150 ℃. The voltage variation of the biomimetic adaptive thermoelectric device prepared in Example 1 with temperature is shown in the figure below. Figure 5 The output voltage shown maintains a linear relationship with temperature changes. However, once a certain threshold is exceeded (highlighted in black), the voltage rise deviates from this linear relationship due to the bending response induced by the high-temperature object. The device was cycled 25 times between -55°C and 60°C, exhibiting minimal voltage fluctuations and excellent repeatability. The temperature cycling test results of the biomimetic adaptive thermoelectric device prepared in Example 1 at -55°C and 60°C are shown in the figure below. Figure 6 As shown, when the heat source temperature is 40 ℃ and the distance to the heat source increases from 0 cm (contact) to 0.5 cm (non-contact), the output voltage drops from 4.67 mV to 1.46 mV, which can realize thermal proximity detection.

[0076] Figure 7 The curves showing the driving temperature of the biomimetic adaptive thermoelectric device provided in this application vary with the thickness of the PDMS layer and the PI layer, respectively. The left side represents the PDMS layer, and the right side represents the PI layer. With a PI film thickness of 60 μm and PDMS film thicknesses of 140, 175, 215, 255, and 290 μm, the driving temperature of the thermoelectric device decreases linearly with increasing PDMS layer thickness. With a PDMS thickness of 255 μm and PI film thicknesses of 15, 25, 35, 50, and 60 μm, the driving temperature of the thermoelectric device also shows a good linear relationship with increasing PI layer thickness, increasing linearly. Therefore, the driving temperature can be precisely adjusted by changing the thickness of the double-layer film.

[0077] The biomimetic adaptive thermoelectric device of Example 1 was subjected to a displacement of 0–4 mm using a mechanical testing machine, and the resistance change was recorded using a Keithley DMM7510. The minimum detectable displacement was 0.03 mm, and the resistance change showed a piecewise linear relationship with the displacement. After 140,000 cycles of testing with a displacement amplitude of 4 mm and a period of 3 seconds, the resistance response amplitude showed only slight decay, indicating excellent responsiveness and fatigue resistance. The durability can be attributed to the abundant polar hydroxyl groups in the BC molecule, which form hydrogen bonds and van der Waals forces with the PI matrix, enhancing the bonding strength between the film and the matrix, thereby improving bending stability. The stability test results of the biomimetic adaptive thermoelectric device prepared in Example 1 after 140,000 loading / unloading cycles are shown in the figure below. Figure 8 As shown.

[0078] The simulated thermal deformation diagrams of the biomimetic adaptive thermoelectric device prepared in Example 1 at a heat source temperature of 120 °C and wind speeds of 1.5 and 10 m / s are shown below. Figure 9 As shown.

[0079] As can be seen from the above embodiments and performance tests, the biomimetic adaptive thermoelectric device provided in this application achieves seamless integration of multimodal high-sensitivity sensing and thermal self-driving through the collaborative design of the sensing layer, thermal driving part and encapsulation layer. It has excellent mechanical stability, environmental adaptability and thermal self-adaptability. The preparation method adopts mature processes such as drop casting, spin coating and screen printing. It is easy to operate, the parameters are controllable, and it can be mass-produced. It has broad application prospects in the fields of smart electronics, wearable medical devices, industrial safety early warning and other fields.

[0080] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and application concept of this application, should be included within the scope of protection of this application.

Claims

1. A biomimetic adaptive thermoelectric device, characterized in that, Includes sensor thin film, conductive electrodes, and substrate; The sensor film includes an actuation layer and a sensing layer arranged sequentially. The actuation layer includes a polydimethylsiloxane layer and a polyimide layer, with the polyimide layer located near the sensing layer. The sensing layer includes tellurium nanowires, a conductive polymer, and bacterial cellulose. The conductive electrode is a stretchable silver paste. The substrate is PDMS with grooves, and a liquid metal circuit is provided on the surface of the grooves. The sensor film is inserted into the grooves so that the sensing layer and the liquid metal circuit are completely bonded. A PDMS encapsulation layer is provided on the surface of the liquid metal circuit.

2. The biomimetic adaptive thermoelectric device according to claim 1, characterized in that, The liquid metal in the liquid metal circuit includes one or more of gallium, indium, or tin, and the mass ratio of gallium, indium, and tin is (65-70):(20-25):

10.

3. The biomimetic adaptive thermoelectric device according to claim 1, characterized in that, The conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate).

4. The biomimetic adaptive thermoelectric device according to claim 1, characterized in that, The temperature detection range of the sensing layer is -120 ℃ to 150 ℃, the temperature sensitivity is 0.2 ℃, and the pressure resolution is 0.03 mm.

5. The biomimetic adaptive thermoelectric device according to claim 1, characterized in that, The sensor film is positioned at an angle of 55° to 60° to the substrate.

6. The biomimetic adaptive thermoelectric device according to claim 1, characterized in that, The length of the sensor film is 7 mm to 9 mm, and the width of the sensor film is 2 mm to 4 mm.

7. A method for fabricating a biomimetic adaptive thermoelectric device, characterized in that, include: A PDMS layer and a sensing layer are formed on both sides of a polyimide film to obtain a sensor film. A stretchable silver paste is then placed on the surface of the sensor film as a conductive electrode. A groove is provided on the substrate surface, and a liquid metal circuit is formed on the surface of the groove. The sensor film is inserted into the groove so that the sensing layer is completely attached to the liquid metal circuit. A PDMS encapsulation layer is formed on the surface of the liquid metal circuit to obtain a biomimetic adaptive thermoelectric device.

8. The preparation method according to claim 7, characterized in that, The forming layer comprises spin-coating a mixture of polydimethylsiloxane main agent and curing agent onto the surface of a polyimide film and curing it to form a PDMS layer. The curing time is 5 h to 6 h and the curing temperature is 50 ℃ to 70 ℃.

9. The preparation method according to claim 7, characterized in that, The thickness of the PI film is 15 μm to 60 μm, and the thickness of the PDMS layer is 140 μm to 290 μm.

10. The preparation method according to claim 8, characterized in that, The mass ratio of the polydimethylsiloxane main agent to the curing agent is (9-12):1, and the curing agent is SYLGARD 184 part B.

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