Self-Powered Flexible Sensor Based on Pressure and Temperature, Its Fabrication Method and Application

Abstract

The present invention discloses a self-powered flexible sensor based on pressure and temperature, its manufacturing method and application. The sensor includes a lower electrode layer, a thermoelectric self-powered layer, a thermal resistance sensing layer, an interlocked pressure-sensitive layer, and an upper electrode layer which are stacked in sequence from bottom to top. The lower electrode layer and the upper electrode layer are used to measure the potential difference generated by the thermoelectric self-powered layer due to the temperature difference between the measured object and the environment. The interlocked pressure-sensitive layer includes an upper pressure-sensitive layer and a lower pressure-sensitive layer. Microstructures are provided on the two opposite surfaces of the upper pressure-sensitive layer and the lower pressure-sensitive layer and form an interlocked connection. Under the action of pressure, the contact area between the upper pressure-sensitive layer and the lower pressure-sensitive layer is changed and a resistance change is generated. The thermal resistance sensing layer is filled with liquid metal, and the contact area between the thermoelectric self-powered layer and the lower pressure-sensitive layer is changed through the volume change of the liquid metal and a resistance change is generated. Due to the resistance changes of the thermal resistance sensing layer and the interlocked pressure-sensitive layer, combined with the potential difference generated by the thermoelectric self-powered layer, pressure and temperature decoupling is finally realized.

Description

Technical Field

[0001] The present invention relates to the field of sensors, in particular to a self-powered flexible sensor based on pressure and temperature, a manufacturing method thereof, and an application thereof. Background Art

[0002] With the rapid development of the fields of artificial intelligence, Internet of Things, and electronic skin, the demand for sensors capable of measuring the surrounding environment is increasing continuously. Flexible sensors have the characteristics of deformability, miniaturization, and light weight. Compared with rigid sensors that cannot fit complex curved surfaces or cannot achieve large-scale bending, flexible sensors can seamlessly fit on the surface of the object to be detected through deformation and stretching without affecting their sensing performance. Therefore, they can meet the application requirements and have been widely studied.

[0003] In biological signal detection or industrial applications, it is usually necessary to collect two or more external signals. As a stretchable electronic detection device that can respond to external stimuli, most current sensing devices can only detect one signal. Therefore, in order to obtain information on multiple signals simultaneously, it is usually necessary to arrange multiple sensors in the system, which not only has a complex layout structure but also requires separate processing of the collected signals. By integrating multiple required sensing functions into a flexible sensor, the above problems can be effectively solved.

[0004] Generally, there are three strategies for the design of sensors with multiple sensing functions, namely integrating multiple sensing units, developing multifunctional materials, and decoupling detection signals. Integrating multiple sensing units can detect multiple signals without crosstalk, but the structure design and manufacturing are relatively complex, and the integration degree is low; developing multifunctional materials can utilize the characteristics that the same material can respond to multiple signals, but there is a problem of difficult signal differentiation; according to the sensing mechanisms of pressure and temperature stimuli, combined with material and structure design, decoupled multiple signal detections can be realized in a single device.

[0005] Flexible sensors can generally detect signals such as pressure, strain, temperature, humidity, and proximity. Among various types of flexible sensors, sensors for detecting pressure and temperature signals are the most widely used. Therefore, developing a single device that can simultaneously achieve crosstalk-free detection of pressure and temperature signals is of great research significance for flexible sensors. The development of flexible sensors for pressure and temperature detection is in its infancy, and there are still problems such as complex structure, expensive manufacturing process, and signal interference between units. At the same time, since multiple signal detection functions can be realized in a single device, the performance of the sensor will inevitably be reduced. Therefore, it is of great significance to develop a flexible sensor with a simple process, scalability, easy decoupling, and excellent sensing performance. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies existing in the prior art and provide a self-powered flexible sensor based on pressure and temperature, as well as a manufacturing method and application thereof.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A self-powered flexible sensor based on pressure and temperature, comprising a lower electrode layer, a thermoelectric self-powered layer, a thermal resistance sensing layer, an interlocking pressure-sensitive layer, and an upper electrode layer that are sequentially stacked from bottom to top; the lower electrode layer and the upper electrode layer are used to measure the potential difference generated by the thermoelectric self-powered layer due to the temperature difference between the measured object and the environment; the interlocking pressure-sensitive layer includes an upper pressure-sensitive layer and a lower pressure-sensitive layer, and microstructures are provided on two opposite surfaces of the upper pressure-sensitive layer and the lower pressure-sensitive layer and form an interlocking connection, and the contact area of the upper pressure-sensitive layer and the lower pressure-sensitive layer is changed under the action of pressure and a resistance change is generated; the thermal resistance sensing layer includes a first polymer provided with a through groove, and a liquid metal is filled in the groove, and the contact area between the thermoelectric self-powered layer and the lower pressure-sensitive layer is changed through the volume change of the liquid metal under the action of temperature change and a resistance change is generated.

[0009] Preferably, the microstructure is one or more of ridge-shaped, conical, pyramid-shaped, cylindrical, and hemispherical structures arranged in an array form.

[0010] Preferably, the groove includes a spiral groove, a through hole is provided in the center of the spiral groove, the liquid metal is filled in the through hole and extends at most to one-fourth of the spiral groove, and is in electrical connection with the lower surface of the lower pressure-sensitive layer and the upper surface of the thermoelectric self-powered layer.

[0011] Preferably, the thermoelectric self-powered layer is composed of a mixture of a thermoelectric material and a second polymer, and the thermoelectric material is one or more of graphene, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), polyaniline, poly(3-hexylthiophene-2,5-diyl), polypyrrole, and polyvinylidene fluoride.

[0012] Preferably, the interlocking pressure-sensitive layer is composed of a mixture of a conductive material and a third polymer, and the conductive material is one of carbon nanotubes, carbon black, carbides, gold nanoparticles, and silver nanowires.

[0013] Preferably, the first polymer, the second polymer, and the third polymer are one or more of polydimethylsiloxane, Ecoflex, polyvinyl alcohol, polyimide, polyurethane, and polyethylene terephthalate.

[0014] Preferably, the elastic modulus of the interlocking pressure-sensitive layer is less than the elastic moduli of the thermal resistance sensing layer and the thermoelectric self-powered layer.

[0015] A manufacturing method of a self-powered flexible sensor based on pressure and temperature, comprising the following steps:

[0016] 1) Put the conductive material into the prepared polymer solution, stir, and after uniform mixing, dry and cure to obtain a pressure-sensitive layer containing the first polymer and the conductive material. Use laser processing technology to form microstructures on the surface of the pressure-sensitive layer, and use two pressure-sensitive layers with microstructures as the upper pressure-sensitive layer and the lower pressure-sensitive layer respectively, and assemble them face to face to form an interlocked pressure-sensitive layer;

[0017] 2) Dry and cure the prepared second polymer solution to obtain a solidified body. Use laser processing technology to create through channels on the solidified body, and use laser processing technology to create through channels on the solidified body to form a thermal resistance sensing layer;

[0018] 3) Put the thermoelectric material into the prepared polymer solution, stir, and after uniform mixing, dry and cure to obtain a thermoelectric self-powered layer containing the third polymer and the thermoelectric material;

[0019] 4) Bond the thermoelectric self-powered layer, the thermal resistance sensing layer, and the interlocked pressure-sensitive layer together in sequence, and use magnetron sputtering vacuum coating technology to form an upper electrode layer and a lower electrode layer above the interlocked pressure-sensitive layer and below the thermoelectric self-powered layer respectively.

[0020] An application of the self-powered flexible sensor based on pressure and temperature according to the above in measuring pressure and / or temperature.

[0021] Preferably, when the detected physical quantity of the object to be measured is only temperature, the relationship between the electromotive force and the temperature is obtained according to the following formula:

[0022] E = S×(T - T0);

[0023] Wherein, E is the electromotive force generated by the thermoelectric self-powered layer; T and T0 are the temperature of the object to be measured and the ambient temperature respectively; S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-powered layer;

[0024] When the detected physical quantity of the object to be measured is only pressure, the relationship between the resistance value and the pressure is obtained according to the following formula:

[0025] R = R0×(1 + α·P);

[0026] Wherein, R and R0 are the resistance value and the initial resistance value of the self-powered flexible sensor under the action of pressure respectively; α is the physical constant of the self-powered flexible sensor itself; P is the pressure applied by the object to be measured;

[0027] When the detected physical quantity of the object to be measured is temperature and pressure, the temperature measurement and pressure measurement are obtained according to the following formula:

[0028] E = S×(T - T0);

[0029] V t = V0(1 + β(T - T0));

[0030] R 热 = R 热0 ·V0 / V t ;

[0031] R 电 = K·R 热 ;

[0032] R 压 - R 压0 = (R - R0) - (R 热 - R 热0 ) - (R 电 - R 电0 );

[0033] Among them, E is the electromotive force generated by the thermoelectric self-powered layer, T and T0 are the temperature of the object to be measured and the ambient temperature respectively, S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-powered layer, V t , V0 are the volumes of the liquid metal at the corresponding temperature and the initial temperature respectively; β is the volume expansion coefficient of the liquid metal, R 电 , R 电0 are the resistance values and the initial resistance values of the thermoelectric self-powered layer in the measured state respectively, R 热 , R 热0 are the resistance values and the initial resistance values of the thermal resistance sensing layer in the measured state respectively, R 压 , R 压0 are the resistance values and the initial resistance values of the interlocking pressure-sensitive layer in the measured state respectively, R and R0 are the resistance values and the initial resistance values of the self-powered flexible sensor in the measured state respectively, and K is the proportionality coefficient of the resistance value of the thermal resistance sensing layer to the resistance value of the thermoelectric self-powered layer at the same temperature.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention uses flexible materials, enabling the sensor to seamlessly fit the surface of the object to be measured, and the polymer materials used have good biocompatibility and can be used as a sensing device for biological signal detection.

[0036] (2) The present invention adopts an interlocking pressure-sensitive layer with a micro-structure, which can effectively improve the sensitivity to pressure; the thermal resistance sensing layer can reduce the heat conduction between the interlocking pressure-sensitive layer and the thermoelectric self-powered layer, reducing or avoiding the change in the resistance of the interlocking pressure-sensitive layer caused by temperature changes; by utilizing the thermal expansion and contraction effect of the liquid metal, the resistance change caused by the change in the volume of the liquid metal with temperature can be stably obtained.

[0037] (3) In the present invention, since the thermoelectric self-power supply layer in contact with the thermal resistance sensing layer is close to the ambient temperature, the thermoelectric material used in the thermoelectric self-power supply layer can utilize the temperature gradient between the surface of the object to be measured and the environment to generate a potential difference; the base material selected for the interlocking pressure-sensitive layer has an elastic modulus smaller than that of the thermal resistance sensing layer and the thermoelectric self-power supply layer, which can ensure that the deformation caused by pressure occurs in the interlocking pressure-sensitive layer. By using the resistance changes of the thermal resistance sensing layer and the interlocking pressure-sensitive layer and combining with the potential difference generated by the thermoelectric self-power supply layer, pressure and temperature decoupling can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The drawings illustrate the embodiments and, together with the description, are used to explain the principles of the present invention. Other embodiments and many of the intended advantages thereof will be readily apparent as they become better understood by reference to the following detailed description.

[0039] Figure 1 Schematic diagram of the self-powered flexible sensor based on pressure and temperature according to an embodiment of the present application;

[0040] Figure 2 Schematic diagram of the interlocking pressure-sensitive layer of the self-powered flexible sensor based on pressure and temperature according to an embodiment of the present application Figure 1 ;

[0041] Figure 3 Schematic diagram of the interlocking pressure-sensitive layer of the self-powered flexible sensor based on pressure and temperature according to an embodiment of the present application Figure 2 ;

[0042] Figure 4 Schematic diagram of the channels of the thermal resistance sensing layer of the self-powered flexible sensor based on pressure and temperature according to an embodiment of the present application;

[0043] Figure 5 Schematic diagram of the thermal resistance sensing layer of the self-powered flexible sensor based on pressure and temperature according to an embodiment of the present application;

[0044] Figure 6 Schematic diagram of the manufacturing process of the interlocking pressure-sensitive layer in the manufacturing method of the self-powered flexible sensor based on pressure and temperature according to Embodiment 1 of the present application;

[0045] Figure 7 Schematic diagram of the manufacturing process of the thermal resistance sensing layer in the manufacturing method of the self-powered flexible sensor based on pressure and temperature according to Embodiment 1 of the present application;

[0046] Figure 8 Schematic diagram of the manufacturing process of the thermoelectric self-power supply layer in the manufacturing method of the self-powered flexible sensor based on pressure and temperature according to Embodiment 1 of the present application;

[0047] Reference numerals: 1, lower electrode layer; 2, thermoelectric self-power supply layer; 3, thermal resistance sensing layer; 31, liquid metal; 32, channel; 41, upper pressure-sensitive layer; 42, lower pressure-sensitive layer; 5, upper electrode layer. Specific embodiments

[0048] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention, rather than limiting the invention. In addition, it should be noted that for the convenience of description, only the parts related to the related invention are shown in the drawings.

[0049] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0050] Refer to Figure 1 , in an embodiment of the present invention, a self-powered flexible sensor based on pressure and temperature is proposed, which includes a lower electrode layer 1, a thermoelectric self-power supply layer 2, a thermal resistance sensing layer 3, an interlocking pressure-sensitive layer, and an upper electrode layer 5 that are sequentially stacked from bottom to top; the upper electrode layer 5 and the lower electrode layer 1 are used to measure the potential difference generated by the thermoelectric self-power supply layer 2 due to the temperature difference between the measured object and the environment; the interlocking pressure-sensitive layer includes an upper pressure-sensitive layer 41 and a lower pressure-sensitive layer 42, and microstructures are provided on the two opposite surfaces of the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 and form an interlocking connection, and the contact area between the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 is changed under the action of pressure and a resistance change is generated; the thermal resistance sensing layer 3 includes a first polymer provided with a through channel 32, a liquid metal 31 is filled in the spiral channel, and the contact area between the thermoelectric self-power supply layer 2 and the lower pressure-sensitive layer 42 is changed by the volume change of the liquid metal 31 under the action of temperature change and a resistance change is generated to achieve decoupling of pressure and temperature. Among them, the upper surface of the upper electrode layer 5 and the upper pressure-sensitive layer 41 are in electrical contact to form an electrical cooperation, the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 are assembled face to face to form an interlocking pressure-sensitive layer, the lower surface of the lower pressure-sensitive layer 42 and the upper surface of the thermal resistance sensing layer 3 are fixedly combined by bonding, the upper surface of the thermal resistance sensing layer 3 and the thermoelectric self-power supply layer 2 are fixedly combined by bonding, and the lower surface of the thermoelectric self-power supply layer 2 and the lower electrode layer 1 are in contact to form an electrical cooperation; the thermal resistance sensing layer 3 has a through channel 32, and the liquid metal 31 filled in the channel 32 is in electrical contact with the lower pressure-sensitive layer 42 and the thermoelectric self-power supply layer 2 respectively to form an electrical cooperation.

[0051] In a specific embodiment, refer to Figure 2 and Figure 3, the microstructures are one or more of ridge-shaped, conical, pyramid-shaped, cylindrical, and hemispherical structures arranged in an array. Specifically, the microstructures are fabricated using laser processing technology. The size range of the side length or diameter of the microstructures is 10-50 μm. The height of the non-spherical microstructures is slightly greater than the side length dimension, and the spacing between the microstructures is slightly less than the side length or diameter of the microstructures. The two pressure-sensitive layers with microstructures are respectively used as the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 and assembled face-to-face to form an interlocking pressure-sensitive layer. Under the action of pressure, the microstructures come into contact with each other and change the contact area, resulting in a change in resistance.

[0052] In a specific embodiment, refer to Figure 4 and Figure 5 The thermal resistance sensing layer 3 is composed of a first polymer and liquid metal 31. The first polymer needs to have good insulation properties and is assembled as an insulating layer between the lower pressure-sensitive layer 42 and the thermoelectric self-power supply layer 2. Specifically, the liquid metal 31 includes a gallium-indium-tin alloy. The channel 32 includes a spiral channel. A through-hole is provided at the center of the spiral channel. The liquid metal 31 is filled in the through-hole and extends at most to one-fourth of the spiral channel, contacting the lower surface of the lower pressure-sensitive layer 42 and the upper surface of the thermoelectric self-power supply layer 2 to form an electrical connection. The channel 32 is fabricated using laser processing technology and penetrates up and down. In one embodiment, the spiral trajectory is an Archimedean spiral, the processing trajectory is 2.5 spiral periods, the spiral direction is clockwise or counterclockwise, the circular through-hole at the center of the spiral starting point is 2 mm in diameter, the width of the spiral channel is 250 μm, the circular through-hole part stores the liquid metal 31, and the channel 32 provides space for the thermal expansion and contraction of the liquid metal 31. The liquid metal 31 is filled into the spiral channel of the polymer. The filling starting point is the center of the spiral channel. First, the through-hole at the center is filled, and then one-fifth of the spiral channel extending from the center through-hole is filled. The liquid metal 31 expands and contracts in the channel 32 with temperature changes, changing the contact area with the lower pressure-sensitive layer 42 and the thermoelectric self-power supply layer 2 and affecting the conductive path, resulting in a change in resistance.

[0053] In a specific embodiment, the thermoelectric self-power supply layer 2 is composed of a mixture of a thermoelectric material and a second polymer. The thermoelectric material is one or more of graphene, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), polyaniline (PANI), poly(3-hexylthiophene-2,5-diyl) (P3HT), polypyrrole (PPy), and polyvinylidene fluoride (PVDF). Specifically, the mass fraction of the thermoelectric material in the thermoelectric self-power supply layer 2 is 10-50 wt.%. When there are multiple thermoelectric materials, the mass ratio of each material is the same. Based on the temperature difference between the measured object and the environment, a potential difference can be generated to supply energy to the sensor to achieve self-power supply.

[0054] In a specific embodiment, the interlocking pressure-sensitive layer is composed of a conductive material and a third polymer mixed together. The conductive material is one of carbon nanotubes (CNT), carbon black (CB), carbides (MXenes), gold nanoparticles (AuNP), and silver nanowires (AgNW). Specifically, the mass fraction of the conductive material in the interlocking pressure-sensitive layer is 5-15 wt.%. Because the conductive material has good electrical conductivity, mixing it into the third polymer makes the originally insulating polymer conductive.

[0055] In a specific embodiment, the first polymer, the second polymer, and the third polymer are one or more of polydimethylsiloxane, Ecoflex, polyvinyl alcohol, polyimide, polyurethane, and polyethylene terephthalate. These polymer materials have a certain flexibility after curing, and based on their material properties, the flexible function of the sensing layer can be realized.

[0056] In a specific embodiment, the elastic modulus of the interlocking pressure-sensitive layer is less than that of the thermal resistance sensing layer 3 and the thermoelectric self-powered layer 2. Therefore, the deformation caused by pressure mainly acts on the interlocking pressure-sensitive layer. The materials of the upper electrode layer 5 and the lower electrode layer 1 are one of gold, silver, and copper; the upper electrode layer 5 and the lower electrode layer 1 are fabricated by magnetron sputtering vacuum coating process, and their thickness is 50-100 nm.

[0057] The embodiment of the present application also proposes a manufacturing method of a self-powered flexible sensor based on pressure and temperature, including the following steps:

[0058] 1) Put the conductive material into the prepared polymer solution and stir. After uniform mixing, dry and cure to obtain a pressure-sensitive layer containing the first polymer and the conductive material. Use laser processing technology to form microstructures on the surface of the pressure-sensitive layer, and use the two pressure-sensitive layers with microstructures as the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 respectively, and assemble them face to face to form an interlocking pressure-sensitive layer;

[0059] 2) Dry and cure the prepared second polymer solution to obtain a cured body. Use laser processing technology to fabricate through channels 32 on the cured body to form the thermal resistance sensing layer 3;

[0060] 3) Put the thermoelectric material into the prepared polymer solution and stir. After uniform mixing, dry and cure to obtain a thermoelectric self-powered layer 2 containing the third polymer and the thermoelectric material;

[0061] 4) Bond the thermoelectric self-powered layer 2, the thermal resistance sensing layer 3, and the interlocking pressure-sensitive layer together in sequence, and use magnetron sputtering vacuum coating process to form the upper electrode layer 5 above the interlocking pressure-sensitive layer and the lower electrode layer 1 below the thermoelectric self-powered layer 2 respectively.

[0062] The following is explained through specific embodiments.

[0063] Example 1

[0064] Embodiment 1 of the present application proposes a manufacturing method of a self-powered flexible sensor based on pressure and temperature, including the following steps:

[0065] (1) As shown in Figure 6 , the third polymer material selected for the interlocking pressure-sensitive layer is PDMS, the conductive material is carbon nanotubes (CNT), the mass fraction of CNT in the interlocking pressure-sensitive layer is 7%, a certain amount of CNT is added to a mixed solution with a prepolymer and a curing agent in a ratio of 10:1, and it is uniformly stirred for 1 h using a magnetic stirrer. The uniformly mixed solution is placed in a vacuum chamber to extract vacuum and maintained for 15 min, and then it is placed in an oven at 70 °C for heat preservation for 6 h to completely cure it. Using laser processing technology, hemispherical microstructures arranged in an array as shown in Figure 2 are fabricated on the cured third polymer. The diameter of the microspheres is 40 μm, the distance between the centers of two microspheres is 75 μm, the laser processing power is 5 W, and the scanning speed is 100 mm / s. Two pressure-sensitive layers with microstructures are respectively used as the upper pressure-sensitive layer 41 and the lower pressure-sensitive layer 42 and assembled face to face to form an interlocking pressure-sensitive layer.

[0066] (2) As shown in Figure 7 , the first polymer material selected for the thermal resistance sensing layer 3 is PVA. Weigh a quantitative amount of PVA powder and add it to deionized water, and perform water bath heating and stirring at 60 °C for 4 h on a magnetic heating stirrer to completely dissolve PVA. After the solution cools, a certain amount of glutaraldehyde and concentrated HCl solution are dropped in to cause a cross-linking reaction of PVA in the solution. After standing for 12 h, it is placed in an incubator at 70 °C for heat preservation for 6 h to obtain the substrate of the thermal resistance sensing layer 3. Using laser processing technology, upper and lower through-channel grooves 32 with a spiral shape are fabricated, as shown in Figure 4 . The laser processing power is 20 W, the scanning speed is 100 mm / s, the spiral trajectory is an Archimedean spiral, the processing trajectory is 2.5 spiral periods, the spiral direction is counterclockwise, the center of the spiral starting point is a through-hole with a diameter of 2 mm, and the width of the spiral groove is 250 μm.

[0067] (3) As shown in Figure 8 , the second polymer material selected for the thermoelectric self-powered layer 2 is PVA, and the thermoelectric material is PEDOT:PSS with a mass fraction of 30%. Weigh a certain amount of PVA powder and PEDOT:PSS solution, add them to deionized water, and perform water bath heating and stirring at 60 °C for 4 h on a magnetic heating stirrer to completely dissolve the PVA powder in deionized water and uniformly mix it with the PEDOT:PSS conductive polymer. After the solution cools, a small amount of pentanediol and concentrated HCl are dropped in to cause a cross-linking reaction of the mixed solution. After standing for 12 h, it is placed in an incubator at 70 °C for heat preservation for 6 h, and the obtained thermoelectric polymer film is the thermoelectric self-powered layer 2.

[0068] (4) The lower surface of the lower pressure-sensitive layer 42, the thermal resistance sensing layer 3, the thermoelectric self-powered layer 2, etc. are subjected to plasma cleaning treatment. The cleaning power is 200 W, the treatment time is 60 s, and the cleaning atmosphere is air; the surfaces after cleaning are bonded, heated at 70 °C for 5 min, and gold films with a thickness of 50 nm are used as the upper electrode layer 5 and the lower electrode layer 1 respectively, and then assembled successively according to Figure 1 the structure. As Figure 5 shown, when assembling the thermal resistance sensing layer 3, the liquid metal 31 gallium-indium-tin alloy is filled into the spiral channels of the first polymer. The filling starting point is the center of the spiral channel. First, the through hole at the center is filled, and one-fifth of the spiral channel extending from the central hole is filled, so as to obtain a self-powered flexible sensor based on pressure and temperature with an interlocking microstructure.

[0069] An embodiment of the present application also proposes an application of the above-mentioned self-powered flexible sensor based on pressure and temperature in measuring the pressure and / or temperature of a measured object.

[0070] In a specific embodiment, when the detected physical quantity of the measured object is only temperature, the relationship between the electromotive force and the temperature is obtained according to the following formula:

[0071] E = S×(T - T0);

[0072] where, E is the electromotive force generated by the thermoelectric self-powered layer 2; T and T0 are the temperature of the measured object and the ambient temperature respectively; S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-powered layer 2;

[0073] When the detected physical quantity of the measured object is only pressure, the relationship between the resistance value and the pressure is obtained according to the following formula:

[0074] R = R0×(1 + α·P);

[0075] where, R and R0 are the resistance value of the self-powered flexible sensor under the action of pressure and the initial resistance value respectively; α is a physical constant of the self-powered flexible sensor itself; P is the pressure applied by the measured object;

[0076] When the detected physical quantity of the measured object is temperature and pressure, the temperature measurement and pressure measurement are obtained according to the following formula:

[0077] E = S×(T - T0);

[0078] V t = V0(1 + β(T - T0));

[0079] R 热 = R 热0 ·V0 / V t ;

[0080] R电 = K·R 热 ;

[0081] R 压 - R 压0 = (R - R0) - (R 热 - R 热0 ) - (R 电 - R 电0 );

[0082] Wherein, E is the electromotive force generated by the thermoelectric self-power supply layer 2, T and T0 are the temperature of the object to be measured and the ambient temperature respectively, S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-power supply layer 2, V t , V0 are the volumes of the liquid metal 31 at the corresponding temperature and the initial temperature respectively; β is the volume expansion coefficient of the liquid metal 31, R 电 , R 电0 are the resistance values and the initial resistance values of the thermoelectric self-power supply layer 2 in the measured state respectively, R 热 , R 热0 are the resistance values and the initial resistance values of the thermal resistance sensing layer 3 in the measured state respectively, R 压 , R 压0 are the resistance values and the initial resistance values of the interlocking pressure-sensitive layer in the measured state respectively, R and R0 are the resistance values and the initial resistance values of the self-powered flexible sensor in the measured state respectively, and K is the proportionality coefficient of the resistance value of the thermal resistance sensing layer 3 and the resistance value of the thermoelectric self-power supply layer 2 at the same temperature.

[0083] In this application, the measured electrical signal includes the potential difference generated by the thermoelectric self-power supply layer 2, and the resistance changes of the thermal resistance sensing layer 3 and the interlocking pressure-sensitive layer. According to the potential difference generated by the thermoelectric self-power supply layer 2 and the resistance change of the thermal resistance sensing layer 3, the temperature can be decoupled; by using the potential difference and resistance change caused by the temperature, the resistance change caused by the pressure is decoupled from the output signal, and the pressure information is decoupled.

[0084] The specific implementation manners of the present application have been described above, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A self-powered flexible sensor based on pressure and temperature, characterized in that, It includes a lower electrode layer, a thermoelectric self-power supply layer, a thermal resistance sensing layer, an interlocked pressure-sensitive layer, and an upper electrode layer that are stacked in sequence from bottom to top; the lower electrode layer and the upper electrode layer are used to measure the potential difference generated by the thermoelectric self-power supply layer due to the temperature difference between the object under test and the environment; the interlocked pressure-sensitive layer includes an upper pressure-sensitive layer and a lower pressure-sensitive layer, and microstructures are provided on two opposite surfaces of the upper pressure-sensitive layer and the lower pressure-sensitive layer and form an interlocked connection, and the contact area between the upper pressure-sensitive layer and the lower pressure-sensitive layer is changed under the action of pressure and a resistance change is generated; the thermal resistance sensing layer includes a first polymer provided with through channels, and a liquid metal is filled in the channels, and the contact area between the thermoelectric self-power supply layer and the lower pressure-sensitive layer is changed by the volume change of the liquid metal under the action of temperature change and a resistance change is generated, and the elastic modulus of the interlocked pressure-sensitive layer is less than the elastic moduli of the thermal resistance sensing layer and the thermoelectric self-power supply layer.

2. The self-powered flexible sensor based on pressure and temperature according to claim 1, characterized in that The microstructures are one or more of ridge-shaped, conical, pyramid-shaped, cylindrical, and hemispherical structures arranged in an array form.

3. The self-powered flexible sensor based on pressure and temperature according to claim 1, characterized in that, The channels include spiral channels, a through hole is provided at the center of the spiral channels, the liquid metal is filled in the through hole and extends at most to one-fourth of the spiral channels, and is in electrical connection with the lower surface of the lower pressure-sensitive layer and the upper surface of the thermoelectric self-power supply layer.

4. The self-powered flexible sensor based on pressure and temperature according to claim 1, wherein The thermoelectric self-power supply layer is composed of a mixture of a thermoelectric material and a second polymer, and the thermoelectric material is one or more of graphene, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), polyaniline, poly(3-hexylthiophene-2,5-diyl), polypyrrole, and polyvinylidene fluoride.

5. The self-powered flexible sensor based on pressure and temperature according to claim 4, characterized in that The interlocked pressure-sensitive layer is composed of a mixture of a conductive material and a third polymer, and the conductive material is one of carbon nanotubes, carbon black, carbides, gold nanoparticles, and silver nanowires.

6. The self-powered flexible sensor based on pressure and temperature according to claim 5, characterized in that, The first polymer, the second polymer, and the third polymer are one or more of polydimethylsiloxane, Ecoflex, polyvinyl alcohol, polyimide, polyurethane, and polyethylene terephthalate.

7. A manufacturing method of a self-powered flexible sensor based on pressure and temperature according to any one of claims 1-6, characterized in that, It includes the following steps: 1) Put the conductive material into the prepared first polymer solution and stir, dry and cure after uniform mixing to obtain a pressure-sensitive layer containing the first polymer and the conductive material, use laser processing technology to form microstructures on the surface of the pressure-sensitive layer, and use the two pressure-sensitive layers with microstructures as the upper pressure-sensitive layer and the lower pressure-sensitive layer respectively and assemble them face to face to form an interlocked pressure-sensitive layer; 2) Dry and cure the prepared second polymer solution to obtain a cured body, and use laser processing technology to make through channels on the cured body to form a thermal resistance sensing layer; 3) Put the thermoelectric material into the prepared polymer solution and stir, dry and cure after uniform mixing to obtain a thermoelectric self-power supply layer containing the third polymer and the thermoelectric material; 4) Bond the thermoelectric self-power supply layer, the thermal resistance sensing layer, and the interlocked pressure-sensitive layer together in sequence, and use magnetron sputtering vacuum coating technology to form an upper electrode layer and a lower electrode layer above the interlocked pressure-sensitive layer and below the thermoelectric self-power supply layer respectively.

8. Application of the pressure- and temperature-based self-powered flexible sensor according to any one of claims 1-6 in measuring pressure and / or temperature.

9. The application according to claim 8, wherein When the detected physical quantity of the object to be measured is only temperature, the relationship between the electromotive force and temperature is obtained according to the following formula: E = S × (T - T0); where, E is the electromotive force generated by the thermoelectric self-powered layer; T and T0 are the temperature of the object to be measured and the ambient temperature respectively; S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-powered layer; When the detected physical quantity of the object to be measured is only pressure, the relationship between the resistance value and pressure is obtained according to the following formula: R = R0 × (1 + α·P); where, R and R0 are the resistance value and the initial resistance value of the self-powered flexible sensor under the action of pressure respectively; α is the physical constant of the self-powered flexible sensor itself; P is the pressure applied by the object to be measured; When the detected physical quantity of the object to be measured is temperature and pressure, the temperature measurement and pressure measurement are obtained according to the following formula: E = S × (T - T0); V t = V0(1 + β(T - T0)); R 热 = R 热0 ·V0 / V t ; R 电 = K·R 热 ; R 压 -R 压0 =(R-R0)-(R 热 -R 热0 )-(R 电 -R 电0 ); Among them, E is the electromotive force generated by the thermoelectric self-powered layer, T and T0 are the temperature of the object to be measured and the ambient temperature respectively, S is the Seebeck coefficient of the thermoelectric material in the thermoelectric self-powered layer, V t , V0 are the volumes of the liquid metal at the corresponding temperature and the initial temperature respectively; β is the volume expansion coefficient of the liquid metal, R 电 , R 电0 are the resistance values of the thermoelectric self-powered layer in the measured state and the initial resistance value respectively, R 热 , R 热0 are the resistance values of the thermal resistance sensing layer in the measured state and the initial resistance value respectively, R 压 , R 压0 are the resistance values of the interlocking pressure-sensitive layer in the measured state and the initial resistance value respectively, R and R0 are the resistance values of the self-powered flexible sensor in the measured state and the initial resistance value respectively, and K is the proportionality coefficient of the resistance value of the thermal resistance sensing layer to the resistance value of the thermoelectric self-powered layer at the same temperature.

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