CN114485976A

CN114485976A - Multifunctional sensor and preparation method thereof

Info

Publication number: CN114485976A
Application number: CN202210052642.0A
Authority: CN
Inventors: 林昇; 陈鲁倬
Original assignee: Fujian Normal University
Current assignee: Fujian Normal University
Priority date: 2022-01-18
Filing date: 2022-01-18
Publication date: 2022-05-13

Abstract

The application relates to a multifunctional sensor and a preparation method thereof. The multifunctional sensor includes a first conductive film, a second conductive film, a first electrode, a second electrode, and a third electrode. The second conductive film is stacked on the first conductive film. The first electrode is electrically connected to the first conductive film. The second electrode is electrically connected to the second conductive film. The third electrode is electrically connected to the first conductive film. The first electrode, the second electrode and the third electrode are not in contact with each other. In the multifunctional sensor, a three-electrode strategy is adopted to set the position of the electrode. The first electrode is a common electrode and is always in a connected state. The other electrodes are non-common electrodes and are electrically connected with different conductive films respectively. Different sensors are operated by switching on different non-common electrodes. The two sensors work separately, and different sensing signals do not influence each other. Meanwhile, the preparation method and the sensor are simple in structure.

Description

Multifunctional sensor and preparation method thereof

Technical Field

The application relates to the field of flexible wearable electronic equipment, in particular to a multifunctional sensor and a preparation method thereof.

Background

Flexible wearable electronic devices are receiving increasing attention due to their wide application in the fields of health monitoring, human-computer interaction, and motion management. Sensors play an important and indispensable role in these fields. In particular, a multifunctional sensor capable of detecting a plurality of environmental signals simultaneously is a hot spot pursued by many researchers. For example, temperature-pressure type electronic skin, which consists of an array of temperature and pressure sensors. In addition, the sensor with humidity and pressure sensing functions is realized by designing a corrugated and porous sponge structure. Although some independent sensors respond to a variety of signals such as pressure, temperature and humidity.

In the conventional technology, the multifunctional sensor has the defects of mutual influence between different sensing signals and complex preparation and structure.

Disclosure of Invention

Therefore, it is necessary to provide a multifunctional sensor and a method for manufacturing the same, aiming at the problems of mutual influence between different sensing signals and complex manufacturing and structure.

A multifunctional sensor includes a first conductive film, a second conductive film, a first electrode, a second electrode, and a third electrode. The second conductive film is stacked on the first conductive film. The first electrode is electrically connected to the first conductive film, the second electrode is electrically connected to the second conductive film, and the third electrode is electrically connected to the first conductive film. The first electrode, the second electrode and the third electrode are not in contact with each other.

In one embodiment, a plurality of first protruding structures are disposed on a surface of the first conductive film close to the second conductive film. The second conductive film is provided with a plurality of second protruding structures close to the surface of the first conductive film.

In one embodiment, the second protrusion structure is provided with a micro protrusion near the surface of the first conductive film.

In one embodiment, the first conductive film comprises a conductive nano material-silk composite film material, and the second conductive film comprises a network structure vein layer.

In one embodiment, the packaging film is further included, and the packaging film wraps the first conductive film and the second conductive film.

In one embodiment, the encapsulation film comprises a flexible polymer material.

In one embodiment, the first electrode and the third electrode are bonded to the first conductive film by silver paste, and the second electrode is bonded to the second conductive film by silver paste.

A method of making a multifunctional sensor, comprising:

a first conductive film and a second conductive film are separately prepared.

A first electrode and a third electrode are provided over the first conductive film, and the first electrode and the third electrode are electrically connected to the first conductive film. And providing a second electrode on the second conductive film to electrically connect the second electrode and the second conductive film.

And covering the first conductive film with the second conductive film, wherein the first electrode, the second electrode and the third electrode are not in contact with each other.

In one embodiment, in the separately preparing the first conductive film and the second conductive film, the method further includes: and mixing the conductive nano material with silk to prepare the first conductive film. The second conductive film is prepared using veins.

In one embodiment, in the step of covering the second conductive film with the first conductive film, and the first electrode, the second electrode, and the third electrode are not in contact with each other, the method further includes: and packaging the first conductive film and the second conductive film by using an encapsulation film.

The embodiment of the application discloses a multifunctional sensor, which adopts a three-electrode strategy to set the position of an electrode. The first electrode is a common electrode and is always in a connected state. When the first electrode is a common electrode, the second electrode and the third electrode are non-common electrodes and are electrically connected to different conductive films respectively. When the multifunctional sensor is in operation, only one of the second electrode and the third electrode is switched on. And switching the second electrode and the third electrode to enable the sensors with different functions to work. Different sensors work separately, and different sensing signals do not influence each other. Meanwhile, the sensor has a simple structure and a simple and convenient preparation method.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic view of a first conductive film according to an embodiment of the present disclosure;

FIG. 2 is a schematic view of a multifunctional sensor provided in an embodiment of the present application;

FIG. 3 is a cross-sectional view of a multifunction sensor provided in accordance with an embodiment of the present application;

FIG. 4 is a schematic view of a multifunctional sensor provided in another embodiment of the present application;

fig. 5 is a flowchart of a method for manufacturing a multifunctional sensor according to an embodiment of the present application.

Description of the reference numerals

The multifunctional sensor comprises a multifunctional sensor 10, a first conductive film 110, a second conductive film 120, a packaging film 130, silver paste 140, a first electrode 111, a third electrode 112, a first protrusion structure 113, a second electrode 121, a second protrusion structure 122 and a micro-protrusion 123.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below by way of embodiments and with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present application and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be considered as limiting the present application.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the conventional art, there are two ways of connecting electrodes of a multifunctional sensor: (1) two electrodes are used. The method can not completely overcome the crosstalk between different environment signals, background signals are mixed in the measured electric signals, post-processing is needed, and the test process and data processing become quite complicated. (2) Four electrodes are used. The sensors prepared by the method are mostly stacked in a sensing array in a single functional mode in an isolated mode, and the structure and the preparation method are complex. During the operation of the device, functional layers responsible for different sensing are not connected, and each of the functional layers plays its own function, so that high integration and integration cannot be realized in the true sense. In order to overcome the disadvantages of the above multifunctional sensors, the present application employs a three-electrode strategy to arrange the electrodes.

Referring to fig. 1 and 2, the present application provides a multi-functional sensor 10. The multifunction sensor 10 includes: a first conductive film 110, a second conductive film 120, a first electrode 111, a second electrode 121, and a third electrode 112. The second conductive film 120 is stacked on the first conductive film 110. The first electrode 111 is electrically connected to the first conductive film 110. The second electrode 121 is electrically connected to the second conductive film 120. The third electrode 112 is electrically connected to the first conductive film 110. The first electrode 111, the second electrode 121, and the third electrode 112 are not in contact with each other.

In the multifunctional sensor 10, the first electrode 111 and the third electrode 112 are each electrically connected to the first conductive film 110. The second electrode 121 is electrically connected to the second conductive film 120. The second conductive film 120 is stacked on the first conductive film 110, and the second conductive film 120 is in contact with the first conductive film 110. The first electrode 111 is a common electrode, and the common electrode is always in an on state. The first electrode 111 is set as the common electrode. When the first electrode 111 and the third electrode 112 are simultaneously turned on, the first conductive film 110, the first electrode 111, and the third electrode 112 constitute one sensor. At this time, the change in the sensing information affects the resistance of the first conductive film 110, and the change in the sensing information can be obtained by measuring the change in the resistance. When the first electrode 111 and the second electrode 121 are simultaneously turned on, the second electrode 121, the second conductive film 120, the first electrode 111, and the first conductive film 110 constitute one sensor. The change in the sensing information affects the resistance between the first conductive film 110 and the second conductive film 120, and the change in the sensing information can be obtained by measuring the change in the resistance.

In the multifunctional sensor 10, a three-electrode strategy is employed to dispose the first electrode 111, the second electrode 121, and the third electrode 112. The first electrode 111 is a common electrode, and the other electrodes are non-common electrodes. The common electrode is always in a connected state, and different sensors work by switching the connected non-common electrode. The sensors in the multifunctional sensor 10 work separately, and different sensing signals do not influence each other. And the structure of the multifunctional sensor 10 is simple.

In one embodiment, the first electrode 111 is a common electrode, and the second electrode 121 and the third electrode 112 are non-common electrodes.

In one particular embodiment, the multifunction sensor 10 is an integrated pressure-temperature sensor. In this case, the first electrode 111, the first conductive film 110, and the third electrode 112 are temperature sensors. When it is required to monitor the ambient temperature, a voltage may be applied to the first electrode 111 and the third electrode 112. Temperature changes affect carrier hopping and tunneling conduction on the first conductive film 110, thereby affecting the resistance of the first conductive film 110. The measured resistance signal can be converted into a temperature signal. The second electrode 121, the second conductive film 120, the first conductive film 110, and the first electrode 111 are pressure sensors. When the pressure needs to be monitored, a voltage is applied to the second electrode 121 and the first electrode 111. Pressure acts on the first conductive film 110 or the second conductive film 120, so that the distance and the contact point between the first conductive film 110 and the second conductive film 120 are changed. The conductive path between the first conductive film 110 and the second conductive film 120 increases and the resistance of the pressure sensor decreases. The resistance signal at this time is measured to obtain a pressure signal.

Referring to fig. 3, in an embodiment, a plurality of first protrusion structures 113 are disposed on a surface of the first conductive film 110 close to the second conductive film 120. The second conductive film 120 is disposed with a plurality of second protrusion structures 122 near the surface of the first conductive film 110.

The surfaces of the first conductive film 110 and the second conductive film 120 are provided with a convex structure. The first protrusion structures 113 are located on the surface of the first conductive film 110 close to the second conductive film 120. The second protrusion structure 122 is located on a surface of the second conductive film 120 close to the first conductive film 110. The first conductive film 110 is in contact with the second conductive film 120, and the first protrusion structure 113 and the second protrusion structure 122 can increase the contact area and the contact point between the two conductive films. The initial resistance between the first conductive film 110 and the second conductive film 120 is small, and the small change of the resistance caused by the sensing information can be clearly measured, thereby improving the sensitivity of the sensor.

In one embodiment, the second protrusion structure 122 is provided with a micro protrusion 123 near the surface of the first conductive film 110.

The second protrusion structure 122 is disposed on the surface of the first conductive film 110, and the minute protrusion 123 is disposed on the surface of the second conductive film. The minute protrusions 123 increase the surface roughness of the second conductive film 120, improving the sensitivity of the sensor. When the pressure applied to the first conductive film 110 or the second conductive film 120 is increased during monitoring of the pressure, the plurality of minute protrusions 123 can be brought into contact with the first conductive film 110. The number of contact points between the first conductive film 110 and the second conductive film 120 increases. When the pressure changes only slightly, enough contact points between the first conductive film 110 and the second conductive film 120 change, and thus a small pressure change can be measured.

In one embodiment, the first conductive film 110 includes a conductive nanomaterial-silk composite film material, and the second conductive film 120 includes a network-structured vein layer.

The conductive nano material-silk composite membrane material is prepared by mixing a conductive nano material and silk. The conductive nano material-silk composite film comprises silk, and the surface of the conductive nano material-silk composite film is provided with the first protruding structures 113. The network structure vein layer is prepared from leaves. The network structure vein layer has a fractal structure and naturally raised grains. The second protrusion structures 122 and the micro protrusions 123 are arranged on the surface of the network structure vein layer, and the surface roughness is large, so that the improvement of the conductive efficiency is facilitated. If the first conductive film 110 and the second conductive film 120 both include the conductive nanomaterial-silk composite film material. At this time, the surface roughness of the first conductive film 110 and the second conductive film 120 is not sufficient, and the sensitivity of the sensor is poor. The network structure vein layer is prepared by soaking the treated veins in a conductive solution, has lower conductive efficiency than the conductive nano material-silk composite film, and is easy to be influenced. If the first conductive film 110 and the second conductive film 120 both comprise the network-structured leaf layer. In this case, the initial resistance of the sensor is large, and the sensitivity is poor. Therefore, the first conductive film 110 and the second conductive film 120 are respectively designed into a conductive nano material-silk composite film material and a network structure vein layer.

In one embodiment, the first conductive film 110 includes the network-structured vein layer, and the second conductive film 120 includes the conductive nanomaterial-silk composite film material.

In one embodiment, the conductive nanomaterial may be MXene (michaene).

In one embodiment, the conductive nanomaterial may be replaced with a material that is conductive and easily moldable, such as a conductive polymer. The conductive polymer comprises one or the combination of more than two of carbon nano tubes, graphene, reduced graphene oxide, fullerene, polyaniline, polypyrrole, polythiophene, polyacetylene and polydiacetylene.

Referring to fig. 4, in one embodiment, the multifunctional sensor 10 further includes an encapsulation film 130. The encapsulation film 130 wraps the first conductive film 110 and the second conductive film 120.

The encapsulation film 130 wraps the first conductive film 110 and the second conductive film 120. The encapsulation film 130 protects the multifunctional sensor 10 from environmental information other than the environmental information to be detected when it is in operation.

In one embodiment, the encapsulation film 130 includes a flexible polymer material.

The first conductive film 110 and the second conductive film 120 are wrapped by the flexible polymer material as the encapsulation film 130. The multifunctional sensor 10 is formed to be flexible as a whole. In practical applications, the multifunction sensor 10 may be compatible with other wearable devices.

In one embodiment, the flexible polymer material may be one or a combination of two or more of polyethylene terephthalate, biaxially oriented polypropylene, polyethylene, silicone rubber, fluorosilicone rubber, polymethyl methacrylate, polyurethane, epoxy resin, polyethylacrylate, polybutyl acrylate, polystyrene, polybutadiene, or polyacrylonitrile.

In one embodiment, the first electrode 111 and the third electrode 112 are adhered to the first conductive film 110 by silver paste 140. The second electrode 121 is adhered to the second conductive film 120 by silver paste 140.

The first electrode 111 and the third electrode 112 are bonded to the first conductive film 110 by the silver paste 140. The second electrode 121 is adhered to the second conductive film 120 by the silver paste 140. The silver paste 140 has conductivity. The first electrode 111, the second electrode 121, and the third electrode 112 are bonded by the silver paste 140, and the first electrode 111, the second electrode 121, and the third electrode 112 may be electrically connected to a conductive film.

Referring to fig. 5, the present application provides a method for manufacturing a multifunctional sensor, including:

s10, the first conductive film 110 and the second conductive film 120 are respectively prepared.

S20, a first electrode 111 and a third electrode 112 are provided on the first conductive film 110, and the first electrode 111 and the third electrode 112 are electrically connected to the first conductive film 110. A second electrode 121 is provided over the second conductive film 120, and the second electrode 121 is electrically connected to the second conductive film 120.

S30, the second conductive film 120 is covered on the first conductive film 110, and the first electrode 111, the second electrode 121, and the third electrode 112 are not in contact with each other.

In S30, the multifunctional sensor 10 is formed by covering the first conductive film 110 with the second conductive film 120. At this time, the first electrode 111, the second electrode 121, and the third electrode 112 are not in contact with each other. Any two electrodes of the first electrode 111, the second electrode 121, and the third electrode 112 are in contact with each other. At this time, the two contacted electrodes are short-circuited, and the sensor cannot normally operate.

In one embodiment, the first electrode 111, the second electrode 121, and the third electrode 112 may be copper foils.

In one embodiment, in S10, the method further includes: the first conductive film 110 is made by mixing conductive nano materials with silk. The second conductive film 120 is prepared using leaves.

In one embodiment, preparing the first conductive film 110 includes: and mixing the conductive nano material solution and the silk according to a mass ratio of 2:3, and performing ultrasonic treatment, magnetic stirring and suction filtration on the mixture of the conductive nano material solution and the silk to obtain the first conductive film 110.

In one embodiment, the preparation of the conductive nanomaterial includes: an etching solution is prepared. And adding the raw material powder of the conductive nano material into the etching solution to prepare the etched mixed solution. And adjusting the mixed solution to make the pH value of the mixed solution neutral. And filtering the mixed solution, and drying the precipitate obtained by filtering to obtain the conductive nano material. And placing the conductive nano material in deionized water to obtain the conductive nano material solution.

In one embodiment, preparing the silk comprises: boiling the silkworm cocoon in weak alkaline solution or deionized water. And washing the silkworm cocoons by using deionized water to obtain the silk.

In one embodiment, preparing the second conductive film 120 includes: the leaves were treated in a boiling alkaline solution and the surface impurities of the leaves were washed off with deionized water. And removing mesophyll on the surface of the leaf, and drying to obtain vein. And placing the conductive nano material in deionized water to obtain the conductive nano material solution. The veins are repeatedly immersed in the conductive nanomaterial solution to obtain the second conductive film 120.

In one embodiment, in S40, the method further includes: the first conductive film 110 and the second conductive film 120 are wrapped with an encapsulation film 130.

In one embodiment, the first conductive film 110 is adhered to the encapsulation film 130 by a double-sided adhesive tape, and the second conductive film 120 is adhered to the encapsulation film 130 by a double-sided adhesive tape.

In a specific embodiment, a bifunctional integrated sensor constructed by an MXene (Michelene) -silk composite membrane and a fractal network structure vein layer is prepared.

1. Preparation of MXene (Mike alkene) -silk composite membrane:

first, HF (hydrogen fluoride) was obtained by magnetically stirring 25ml of a 12mol/L HCl (hydrogen chloride) solution, 2.3g of LiF (lithium fluoride) solution and 5ml of deionized water for 5 minutes. 1g of a commercial MAX phase powder was slowly added to the above solution at three time intervals, and the above solution was stirred at a temperature of 80 ℃ for 72 hours to etch Al (aluminum) element. Subsequently, the resulting etched solution was centrifuged and washed several times until the pH of the etched solution reached 7, and a precipitate was obtained. The precipitate was placed in a vacuum oven and dried at 60 ℃ for 24 hours to obtain MXene (Meikeen). 2g of silkworm cocoon at 100 ℃, 200ml of Na with the concentration of 0.05mol/L₂CO₃After boiling the solution for 3 hours, the solution is washed by deionized water to obtain silk. The silk was sonicated at 90% power for 20 minutes. And finally, mixing MXene (Michelene) and the silk according to the mass ratio of 2:3, magnetically stirring for 10 minutes, and carrying out suction filtration to obtain the MXene (Michelene) -silk composite membrane.

2. Preparing a vein layer with a fractal network structure:

first, fresh bodhi leaves are immersed into a NaOH solution having a solubility of 10% at 100 ℃ and boiled for 10 minutes, and then the impurities on the surfaces of the bodhi leaves are washed with deionized water. Then, the mesophyll on the surface of the bodhi leaves was brushed off with a brush. Drying the linden leaves in an oven at 50 ℃ for 30 minutes to obtain a vein layer. Cutting the vein layer to an appropriate size. And (3) dipping the veins in MXene (Michelene) solution prepared previously for several times to obtain a fractal network structure vein layer with good conductivity.

3. Three-electrode strategy connecting electrodes:

first, a copper foil is cut into strips with appropriate length and width, and three strips are prepared for standby. The MXene (Meikeken) -silk composite membrane was torn off the filter and cut into a 5cm by 2cm rectangle. Then, two copper foil electrodes are respectively adhered to two ends of the MXene (Michelene) -silk composite membrane by using silver adhesive. Finally, the impregnated layer of the fractal network structure veins is cut into a rectangle of approximately 6cm by 2 cm. Meanwhile, the remaining copper foil electrode is adhered to one end of the fractal network structure vein layer by using silver adhesive, and three electrodes are not contacted with each other when the MXene (Michelene) -silk composite membrane and the fractal network structure vein layer are laminated. The distance between the two nearest electrodes is not less than 0.5 cm.

4. Polyethylene terephthalate (PET) film encapsulation:

first, a polyethylene terephthalate film was cut into a 7cm by 3cm rectangular shape, and was adhered to one surface of the polyethylene terephthalate film with a double-sided adhesive tape. Then, the MXene (Michelene) -silk composite film with the electrodes adhered is fixed on the polyethylene terephthalate film by using a double-sided adhesive tape. The MXene (maikeen) -silk composite film is smaller than the polyethylene terephthalate film, so that the position of the MXene (maikeen) -silk composite film is that the left end of the polyethylene terephthalate film is left with a space of 0.5cm, the right end of the polyethylene terephthalate film is left with a space of 1.5cm, the upper part and the lower part of the polyethylene terephthalate film are centered, and each space is 0.5 cm. And finally, fixing the vein layer of the fractal network structure by using a similar method. The positions of the fractal network structure vein layer on the ethylene terephthalate film are that the left end is left empty by 0.5cm, the right end is left empty by 0.5cm, the upper part and the lower part are centered, and each empty is 0.5 cm. And the redundant ethylene terephthalate film is compressed by a double-sided adhesive tape, so that air and moisture are isolated, and the device is prevented from being interfered by the external environment when in work.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present patent. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A multi-functional sensor, comprising:

a first conductive film (110);

a second conductive film (120) which is provided in a stacked manner with the first conductive film (110);

a first electrode (111) electrically connected to the first conductive film (110);

a second electrode (121) electrically connected to the second conductive film (120); and

a third electrode (112) electrically connected to the first conductive film (110);

the first electrode (111), the second electrode (121), and the third electrode (112) are not in contact with each other.

2. The multifunctional sensor according to claim 1, wherein a surface of the first conductive film (110) adjacent to the second conductive film (120) is provided with a plurality of first bump structures (113);

the second conductive film (120) is provided with a plurality of second protruding structures (122) close to the surface of the first conductive film (110).

3. The multifunctional sensor according to claim 2, wherein the second bump structure (122) is provided with a minute bump (123) near a surface of the first conductive film (110).

4. The multifunctional sensor of claim 1,

the first conductive film (110) comprises a conductive nano material-silk composite film material;

the second conductive film (120) includes a network-structured vein layer.

5. The multi-functional sensor of claim 1, further comprising:

an encapsulation film (130), the encapsulation film (130) wrapping the first conductive film (110) and the second conductive film (120).

6. Multifunction sensor according to claim 5, characterized in that the encapsulation film (130) comprises a flexible polymer material.

7. The multifunctional sensor according to claim 1, wherein the first electrode (111) and the third electrode (112) are bonded to the first conductive film (110) by silver paste (140), and the second electrode (121) is bonded to the second conductive film (120) by silver paste (140).

8. A method for preparing a multifunctional sensor is characterized by comprising the following steps:

preparing a first conductive film (110) and a second conductive film (120) respectively;

providing a first electrode (111) and a third electrode (112) on the first conductive film (110), and electrically connecting the first electrode (111) and the third electrode (112) to the first conductive film (110), and providing a second electrode (121) on the second conductive film (120), and electrically connecting the second electrode (121) to the second conductive film (120);

the second conductive film (120) covers the first conductive film (110), and the first electrode (111), the second electrode (121), and the third electrode (112) are not in contact with each other.

9. The method for preparing a multifunctional sensor according to claim 8, wherein in the separately preparing the first conductive film (110) and the second conductive film (120), further comprising:

mixing a conductive nano material with silk to prepare the first conductive film (110);

the second conductive film (120) is prepared using veins.

10. The method of claim 8, wherein the step of covering the first conductive film (110) with the second conductive film (120) and the first electrode (111), the second electrode (121), and the third electrode (112) are not in contact with each other, further comprises: the first conductive film (110) and the second conductive film (120) are wrapped with an encapsulation film (130).