CN118731120A - A flexible dielectric sensor, preparation method and application thereof - Google Patents

Abstract

The present application discloses a flexible dielectric sensor, a preparation method and an application thereof, which are composed of a flexible electrode layer and a flexible substrate layer from top to bottom, wherein the flexible electrode layer is prepared from a raw material of a conductive material and has an interdigitated electrode structure; the preparation method of the flexible electrode layer comprises the following steps: S1, pasting a tape on a polymer substrate film; S2, cutting the tape on the surface of the polymer substrate film with a laser beam to form a drop coating groove of the interdigitated electrode structure; S3, drop coating a conductive material solution in the drop coating groove of the interdigitated electrode structure with a syringe, and after the conductive material solution is completely dried, tearing off all the remaining tape on the polymer substrate film to form a flexible electrode layer; the invention is used to solve the technical problem that the existing sensors are basically prepared from rigid materials, and when embedded in a composite material for curing degree monitoring, the original mechanical properties of the composite material will be reduced to a certain extent.

Description

A flexible dielectric sensor, preparation method and application thereof

Technical Field

The present application relates to the technical field of marine composite material solidification monitoring, and in particular to a flexible dielectric sensor, a preparation method and application thereof.

Background Art

As the largest ecosystem on earth, the ocean is rich in mineral resources such as oil and natural gas. With the strong support of national policies, marine technology has been fully developed. However, the marine environment is very complex. High concentrations of salt and oxygen can easily corrode metals, concrete, wood and other materials, greatly reducing the service life of offshore equipment; the high-pressure environment of the deep sea also brings great operational difficulties to deep-sea equipment such as submersibles. In addition, waves, ocean currents, and extreme weather such as tsunamis and hurricanes also pose a major threat to maritime navigation and ship structures. Composite materials are widely used in marine technology because of their corrosion resistance, high pressure resistance, light weight and customizability. As early as the early days after World War II, composite materials were used in the marine industry to solve the corrosion problems of traditional steel, aluminum and wood; in ship applications, the use of composite materials to make hulls and decks has the advantage of light weight, which can reduce the overall weight of the ship, improve navigation speed and fuel efficiency, and the application of composite materials in the ocean has been continuously expanded and deepened, covering offshore wind power, transportation, deep-sea mining, submarine oil and gas exploration and other fields.

In the prior art CN107796787A, the curing of composite materials is monitored by utilizing the change of refractive index in optical fiber sensing. This method requires the optical fiber sensor to be embedded in the composite material, and the placement of the optical fiber sensor in the composite material has certain restrictions. Improper placement can easily affect the refractive index of light, resulting in inaccurate monitoring of the degree of curing. In addition, the current optical fiber sensor is basically made of rigid materials, so when embedded in the composite material, the original mechanical properties of the composite material will be reduced to a certain extent.

To solve the problems existing in the above-mentioned prior art, a flexible sensor is needed which can adapt to the internal environment of the marine composite material when embedded in the marine composite material, and the sensor is embedded in the marine composite material to monitor the degree of curing.

Summary of the invention

The embodiments of the present application provide a flexible dielectric sensor, a preparation method and an application thereof, which are used to solve the technical problem that the existing sensors are basically made of rigid materials, so when embedded in composite materials for curing degree monitoring, the original mechanical properties of the composite materials will be reduced to a certain extent.

In view of this, the present application provides a flexible dielectric sensor, which is composed of a flexible electrode layer and a flexible substrate layer from top to bottom, wherein the flexible electrode layer is prepared from a raw material of a conductive material, and the flexible electrode layer is an interdigital electrode structure;

The method for preparing the flexible electrode layer comprises the following steps:

S1, pasting tape on the polymer substrate film;

S2, cutting the tape on the surface of the polymer substrate film with a laser beam, and tearing off the cut portion, so that the remaining tape forms a drop coating groove with an interdigitated electrode structure;

S3, using a syringe to drip a conductive material solution in the dripping groove of the interdigitated electrode structure, and after the conductive material solution is completely dried, the remaining tape on the polymer substrate film is completely torn off, so that a flexible electrode layer is formed on the polymer substrate film.

Optionally, the flexible base layer is a polydimethylsiloxane-based base layer.

Optionally, the polymer substrate is selected from at least one of polyethylene, polypropylene, fiber paper, leather, polyimide, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyurethane, silicone rubber, fluororubber, and thermoplastic elastomer.

Optionally, the conductive material includes at least one of graphene, carbon nanotubes, gold nanowires, silver nanowires, copper nanowires and metal nanoparticles.

Optionally, the method for preparing the conductive material solution consists of the following steps:

A1. Pour ethylene glycol solution into a beaker, add polyvinyl pyrrolidone, and stir until the solution becomes clear to obtain a first solution;

A2, grinding the prepared silver nitrate particles into powder, adding the powder into the first solution and stirring magnetically, and then adding ferric chloride solution and stirring to obtain a second solution;

A3, allowing the prepared second solution to react, and obtaining silver nanowires after the reaction is completed;

A4, washing the silver nanowires in an acetone solution, and centrifuging and precipitating the silver nanowires, and then discarding the acetone solution after centrifugation to obtain precipitated silver nanowires;

A5. Wash the precipitated silver nanowires for a second time with an ethanol solution, and then disperse the washed silver nanowires into an ethanol solution to obtain a conductive material solution.

Optionally, in step A3, the ambient temperature for the static reaction of the second solution is 100-120 degrees, and the reaction time is 11-13 hours.

The present application also provides a method for preparing a flexible dielectric sensor, comprising the following steps:

B1, pouring the prepared polydimethylsiloxane solution on the flexible electrode layer;

B2. After the polydimethylsiloxane solution completely covers the flexible electrode layer, curing is performed to obtain a prototype of a flexible dielectric sensor;

B3. Tear off the polymer substrate film at the bottom of the flexible dielectric sensor prototype to obtain a flexible dielectric sensor as a whole.

Optionally, in step B2, the curing temperature is 70-90 degrees and the curing time is 20-40 minutes.

The present invention also provides an application of the flexible dielectric sensor described above or the flexible dielectric sensor prepared by the preparation method described above in healthy curing monitoring of marine composite materials.

It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

The present application provides a flexible dielectric sensor, which is composed of a flexible electrode layer and a flexible substrate layer from top to bottom, wherein the flexible electrode layer is prepared from a raw material of a conductive material, and the flexible electrode layer is an interdigitated electrode structure, so that the sensor has good extensibility and softness. When the sensor is embedded in a marine composite material for healthy curing monitoring, the original mechanical properties of the marine composite material can be maintained, thereby realizing non-destructive online monitoring of its curing degree.

The present invention further defines the geometric shape as an in-plane staggered interdigital electrode structure, which achieves a simple structure of the sensor, improves sensitivity, eliminates cross-sensitivity to applied pressure, and improves the reliability of the sensor;

The flexible dielectric sensor provided by the present invention can be used for health monitoring of marine composite materials, that is, monitoring the health status of composite materials. When the composite materials are cracked and aged after long-term immersion in seawater, the sensor promptly sends out abnormal monitoring signals to remind the user to take certain protective measures for the marine composite materials, thereby reducing the probability of marine accidents.

The method for preparing the flexible dielectric sensor provided by the present invention has simple steps, is easy to operate and has high preparation efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly express the technical solutions of the embodiments of the present application, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram of a flexible dielectric sensor provided in an embodiment of the present application;

FIG2 is a schematic diagram of parameters of a flexible dielectric sensor provided in an embodiment of the present application;

FIG3 is a schematic diagram of a method for preparing a flexible dielectric sensor provided in an embodiment of the present application;

FIG4 is a bending test effect diagram of a flexible dielectric sensor provided in an embodiment of the present application;

FIG5 is a diagram showing the effect of a tensile test of a flexible dielectric sensor provided in an embodiment of the present application;

FIG6 is a schematic diagram of a flexible dielectric sensor provided in an embodiment of the present application for monitoring the curing of marine composite materials.

DETAILED DESCRIPTION

In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

For ease of understanding, please refer to FIG3 . The present invention provides a flexible dielectric sensor, which is composed of a flexible electrode layer and a flexible substrate layer from top to bottom. The flexible electrode layer is prepared from a raw material of a conductive material. The flexible electrode layer is an interdigital electrode structure, which has a simple structure, improved sensitivity, and eliminates cross-sensitivity to applied pressure, thereby improving the reliability of the sensor.

The method for preparing the flexible electrode layer consists of the following steps:

S1, pasting tape on the polymer substrate film;

S2, using a laser beam to cut the tape on the surface of the polymer substrate film, and tearing off the cut portion, so that the remaining tape forms a drop coating groove with an interdigitated electrode structure;

S3. Use a syringe to drip a conductive material solution in the drip coating tank of the interdigitated electrode structure. After the conductive material solution is completely dry, tear off all the remaining tape on the polymer substrate film, and a flexible electrode layer is formed on the polymer substrate film.

As a further embodiment of the present invention, the flexible substrate layer is a polydimethylsiloxane (PDMS) substrate layer.

Furthermore, the polymer substrate is selected from at least one of polyethylene, polypropylene, fiber paper, leather, polyimide (PI), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyurethane (PU), silicone rubber, fluororubber and thermoplastic elastomer (TPE). Specifically, the polymer substrate is polyimide (PI).

Furthermore, the conductive material includes at least one of graphene, carbon nanotubes, gold nanowires, silver nanowires, copper nanowires and metal nanoparticles. Specifically, the conductive material is silver nanowires (AgNWs).

Further, the preparation method of the conductive material solution consists of the following steps:

A1. Pour 50 ml of ethylene glycol (EG) solution into a 100 ml beaker, add 0.2 g of polyvinyl pyrrolidone (PVP), and stir until the solution becomes clear to obtain the first solution;

A2. Grind the prepared silver nitrate (AgNO3) particles into powder, take 0.25 g and add it to the mixed first solution, and stir it magnetically with a magnetic stirrer. After stirring, add 3.4 g of ferric chloride (FeCl3) solution, and stir for 1 min to obtain the second solution.

A3, then allowing the prepared second solution to react, and after the reaction is completed, silver nanowires are obtained;

A4, washing the silver nanowires (AgNWs) in an acetone solution, and centrifuging and precipitating the silver nanowires (AgNWs) using a centrifuge, and then discarding the acetone solution after centrifugation to obtain precipitated silver nanowires (AgNWs);

A5. The precipitated silver nanowires (AgNWs) are then washed twice with an ethanol solution, and the silver nanowires (AgNWs) after the second washing are dispersed in an ethanol solution to obtain a conductive material solution, that is, a silver nanowire (AgNWs) solution.

Furthermore, in step A3, the ambient temperature for the static reaction of the second solution is 100-120 degrees, specifically 110 degrees, and the reaction time is 11-13 hours, specifically 12 hours.

Specifically, in step S1, a 125 μm polyimide (PI) film is selected as a tearable substrate, and a Kapton tape is pasted on the polyimide (PI) film. The Kapton tape is selected because ordinary tapes have poor viscosity and no toughness, and are easily caused to fall off when cut. The conductive tape is thick and difficult to cut. Compared with other tapes, the thickness of the Kapton tape can reach the micron level, which can meet our preparation needs, and it has extremely high adhesion to the polyimide (PI) film. Without applying external force, the polyimide (PI) film and the Kapton tape will not separate. In addition, the Kapton tape has outstanding heat resistance, and will not deform or age during subsequent heating and curing. When the Kapton tape is removed, the Kapton tape does not leave any residual glue, keeping the surface of the polyimide (PI) clean.

Specifically, in step S2, the Kapton tape on the surface of the polyimide (PI) film is etched and cut by a laser beam emitted by a laser engraving machine, and the cut part is torn off, so that the remaining Kapton tape forms a cross-finger electrode structure drop coating groove, wherein the parameters of the laser engraving machine are that the power frequency is 45 kHz and the power is 1.3 W, which meets the requirements of completely penetrating the Kapton tape covering the polyimide (PI) substrate without damaging the polyimide (PI) substrate, and after tearing off the Kapton tape that has been etched and cut, the surface of the polyimide (PI) is wiped with alcohol to ensure that the surface of the polyimide (PI) is clean.

Specifically, in step S3, a silver nanowire (AgNWs) solution (electrode material) is dripped in a small amount and multiple times in a dripping tank of an interdigitated electrode structure using a syringe. After the silver nanowire (AgNWs) solution is completely dried, the remaining Kapton tape on the polyimide (PI) film is completely torn off, and a silver nanowire (AgNWs) flexible electrode layer is formed on the polyimide (PI) substrate film. The concentration of the silver nanowire (AgNWs) solution is 3 wt.%, so that no lumps are formed on its surface, the conductive performance is excellent, the number of dripping times is reduced, and the workload is reduced.

It should be added that in actual operation, the amount of silver nanowire (AgNWs) solution applied should be properly controlled. While ensuring that the silver nanowire (AgNWs) solution is completely filled in the drop coating groove of the interdigitated electrode structure, try to ensure that there is no overflow of the silver nanowire (AgNWs) solution. After the silver nanowire (AgNWs) solution is initially dried and no longer flows around, it is moved to the heating table for heating. The temperature is controlled at 60°C to speed up the drying process of the silver nanowire (AgNWs) solution and save preparation time. Each time the silver nanowire (AgNWs) solution applied is completely dry, use tweezers to pick up a small amount of dust-free paper and wipe the remaining Kapton tape surface to remove the silver nanowires (AgNWs) remaining on the surface. The silver nanowire (AgNWs) solution that has been completely dried after the drop coating is the electrode material. During the entire coating process, the silver nanowire (AgNWs) solution was coated 10 times in total. After the last coating was completed and completely dried, the remaining Kapton tape on the polyimide (PI) was torn off. When tearing off the Kapton tape, the speed should not be too fast, otherwise some electrodes adhered to the Kapton tape will be removed together, causing electrode damage. Therefore, first use tweezers to clamp a corner of the Kapton tape, slowly lift up the Kapton tape, and use reverse force at the part where the electrode and the Kapton tape are connected to pull the Kapton tape in the opposite direction of the bonding electrode, thereby reducing the electrode from falling off and maintaining the integrity of the electrode. After all the Kapton are torn off, a thin layer of silver nanowires (AgNWs) with uniform thickness and patterning has been formed on the surface of the polyimide (PI), which is the flexible electrode layer.

The present application also provides a method for preparing a flexible dielectric sensor, comprising the following steps:

B1. Pour the prepared polydimethylsiloxane (PDMS) solution onto the flexible electrode layer;

B2. When the polydimethylsiloxane (PDMS) solution completely covers the flexible electrode layer, it is cured to obtain a prototype of a flexible dielectric sensor;

B3. Tear off the polymer substrate film at the bottom of the flexible dielectric sensor prototype to obtain the flexible dielectric sensor as a whole.

Specifically, in step B1, the flexible electrode layer is a patterned silver nanowire (AgNWs) thin layer, that is, a prepared polydimethylsiloxane (PDMS) solution is poured on the patterned silver nanowire (AgNWs) thin layer, wherein the polydimethylsiloxane (PDMS) solution is selected from Dow Corning of the United States, and the polydimethylsiloxane (PDMS) solution: curing agent = 10:1 is mixed according to the requirements of the instructions, and stirred for 5 minutes to ensure that the polydimethylsiloxane (PDMS) solution and the curing agent have been fully mixed and evenly mixed, and then the mixed solution is vacuum degassed in a vacuum drying oven for 10 minutes. After the degassed solution is completed, it is placed for 5 minutes. After the bubbles on the surface of the polydimethylsiloxane (PDMS) solution are completely dissipated, it can be used for pouring on the patterned silver nanowire (AgNWs) thin layer.

Specifically, in step B2, after the polydimethylsiloxane (PDMS) solution completely covers the patterned silver nanowire (AgNWs) thin layer, it is cured to obtain a flexible dielectric sensor prototype. The curing temperature is 70-90 degrees, specifically 80 degrees, and the curing time is 20-40 minutes, specifically 30 minutes. The superior flexibility of polydimethylsiloxane (PDMS) is obtained to meet the requirements of flexible dielectric sensors.

Specifically, in step B3, the polyimide (PI) substrate film at the bottom of the flexible dielectric sensor prototype is torn off to obtain the flexible dielectric sensor as a whole, wherein the dimensions of the flexible dielectric sensor are (see Figure 2): electrode length (L) 20 mm, electrode width (W) 400 μm, electrode interval (G) 400 μm, number of electrodes (N) 20, electrode thickness (h _d ) 80 μm, and thickness of the base polydimethylsiloxane (PDMS) 1 mm.

FIG1 is a schematic diagram of a flexible dielectric sensor provided in an embodiment of the present application, wherein 1 is a polydimethylsiloxane (PDMS) substrate, and 2 is an electrode material silver nanowire (AgNWs).

Figure 2 is a parameter schematic diagram of a flexible dielectric sensor provided in an embodiment of the present application, wherein 1 is an overall schematic diagram of the flexible dielectric sensor, 2 is a schematic diagram of the middle cross-section of the flexible dielectric sensor, and 3 is a partially enlarged schematic diagram of the middle cross-section of the flexible dielectric sensor.

Figure 3 is a schematic diagram of a method for preparing a flexible dielectric sensor provided in an embodiment of the present application, wherein 1 is a laser beam, 2 is a silver nanowire (AgNWs) solution of an electrode material, 3 is a Kapton tape, 4 is a prepared polydimethylsiloxane (PDMS) solution, and 5 is a polyimide (PI) substrate film.

Example 1

The preparation method of the flexible dielectric sensor includes the following steps (see Figure 3):

Preparation of flexible electrode layer:

1-1) A 125 μm polyimide (PI) film was selected as a removable substrate, and a Kapton tape was pasted on the polyimide (PI) film;

1-2) The Kapton tape on the surface of the polyimide (PI) film is etched and cut by a laser beam emitted by a laser engraving machine, and the cut portion is torn off, so that the remaining Kapton tape forms a drop coating groove of an interdigitated electrode structure;

1-3) Using a syringe to apply a silver nanowire (AgNWs) solution (electrode material) in a small amount and multiple times in a drop coating tank of an interdigitated electrode structure, after the silver nanowire (AgNWs) solution is completely dried, the remaining Kapton tape on the polyimide (PI) film is completely torn off, and a silver nanowire (AgNWs) flexible electrode layer is formed on the polyimide (PI) substrate film;

3) The flexible electrode layer is a patterned silver nanowire (AgNWs) thin layer, and a prepared polydimethylsiloxane (PDMS) solution is poured on the patterned silver nanowire (AgNWs) thin layer;

4) After the polydimethylsiloxane (PDMS) solution completely covers the patterned silver nanowire (AgNWs) thin layer, it is cured at a temperature of 80 degrees for 30 minutes to obtain a prototype of a flexible dielectric sensor.

5) The polyimide (PI) substrate film at the bottom of the flexible dielectric sensor prototype is then torn off to obtain the flexible dielectric sensor as a whole, wherein the dimensions of the flexible dielectric sensor are: electrode length (L) 20 mm, electrode width (W) 400 μm, electrode interval (G) 400 μm, number of electrodes (N) 20, electrode thickness (hd) 80 μm, and thickness of the base polydimethylsiloxane (PDMS) 1 mm.

The flexible dielectric sensor obtained in Example 1 was subjected to a bending performance test. The testing instrument and items used in the test included: a stretching machine, an LCR meter, and a fixture.

Detection methods include:

First, the prepared flexible dielectric sensors (size: W = G = 400 μm; N = 20; L = 20 mm) were clamped on the stretching fixture of the stretching machine;

After the flexible dielectric sensor is completely and firmly clamped by the fixture, since the fixture and the flexible dielectric sensor are in a conductive state, we only need to lead out wires on both sides of the fixture and connect them to the LCR meter to test the capacitance value of the flexible dielectric sensor;

After all the connections are completed, first use ordinary tape to fix the position of the lead wire to prevent it from moving significantly during the test, which will lead to inaccurate measurement results. Then calibrate the LCR meter before the test, that is, adjust the LCR meter to the calibration page, first perform open circuit calibration, and then perform short circuit calibration after the open circuit calibration is completed. After completion, the bending test of the flexible dielectric sensor can be officially started;

Then, the stretching machine was set up, and the upper clamp of the stretching clamp was set to perform cyclic motion, and the motion speed was set to 60 mm/min. First, the upper clamp moved downward, and the flexible dielectric sensor was bent by force. After the flexible dielectric sensor was completely bent and folded (i.e., bent 180°), the clamp moved upward and returned to the starting point, and repeated this process for a total of 1000 cycles;

During the bending cycle, the capacitance value is recorded in real time by the LCR meter, and the change of the capacitance value of the sensor with the bending cycle can be clearly observed. It can be found from the test data of capacitance that, as shown in the results of Figure 4, the capacitance value of the flexible dielectric sensor always changes regularly with the bending cycle, and after 1000 cycles, the capacitance value of the flexible dielectric sensor does not change suddenly, and still maintains the same change pattern as the initial stage of the test, indicating that the flexible dielectric sensor has excellent flexibility and stability. Therefore, the bending performance of this flexible dielectric sensor is better.

The flexible dielectric sensor obtained in Example 1 was subjected to a tensile performance test. The testing instrument and items used in the test included: a tensile machine, an LCR meter, and a fixture.

Detection methods include:

First, the prepared flexible dielectric sensor (size: W=G=400 μm; N=20; L=20 mm) was clamped on the stretching fixture of the stretching machine. The two ends of the fixture clamped the electrodes on both sides of the sensor to ensure that the fixture and the sensor were in a conductive state (the stretching fixture and the stretching machine are both made of metal conductors).

After the sensor is completely and firmly clamped by the fixture, since the fixture and the sensor are in a conductive state, it is only necessary to lead out wires on both sides of the fixture and connect them to the LCR meter to test the capacitance value of the sensor. The specific operation is: wrap the thin and long wires around the screws on both sides of the fixture, and connect the wires to the LCR test fixture.

After all the connections are completed, first use ordinary tape to fix the position of the lead wire to prevent it from moving significantly during the test, resulting in inaccurate measurement results. Then, the LCR meter needs to be calibrated before the test. Adjust the LCR meter to the calibration page and perform open-circuit calibration first. After the open-circuit calibration is completed, perform the next step of short-circuit calibration. After completion, the tensile test of the flexible dielectric sensor can be officially started.

The stretching machine was set up, and the upper clamp of the stretching clamp was set to cyclic motion, and the motion speed was set to 60 mm/min. First, the upper clamp moved upward, and the flexible sensor was stretched upward under force. After the flexible sensor was stretched by 9 mm (i.e., the tensile strain was 30%), the clamp moved downward and returned to the starting point, and the cycle was repeated for a total of 1000 times.

During the stretching cycle, the capacitance value recorded in real time by LCR can clearly show how the capacitance value of the sensor changes with the stretching cycle. It can be found from the capacitance test data that the capacitance value of the sensor always changes regularly with the stretching cycle, and after 1000 cycles, the capacitance value of the sensor does not change suddenly, and still maintains the same change pattern as the initial stage of the test, indicating that the flexible dielectric sensor has excellent flexibility and stability.

The flexible dielectric sensor described above or the flexible dielectric sensor prepared by the preparation method described above provided by the present invention is used in the healthy curing monitoring of marine composite materials, that is, the prepared flexible dielectric sensor is embedded in the marine composite material. When the flexible dielectric sensor is embedded in the interior of the marine composite material to monitor the curing process of the marine composite material, it can adapt to the stress changes generated by the composite material during the curing process, so as not to destroy the performance of the composite material after curing, and maintain the high reliability of the composite material in the application. After the curing is completed, the flexible dielectric sensor embedded in the marine composite material can still be used to monitor the health status of the subsequent marine composite material during the application process. That is, when the composite material cracks and ages after long-term immersion in seawater, the flexible dielectric sensor promptly sends a monitoring abnormality signal to remind the marine composite material to take certain protective measures, thereby reducing the probability of marine accidents.

Figure 6 is a schematic diagram of a flexible dielectric sensor provided in an embodiment of the present application embedded in a marine composite material for curing monitoring, wherein 1 is a probe of a temperature sensor, 2 is a wire of the flexible dielectric sensor, 3 is a marine composite material, and 4 is a flexible dielectric sensor.

The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (8)

1. A flexible dielectric sensor, which consists of a flexible electrode layer and a flexible substrate layer from top to bottom, wherein the flexible electrode layer is made of a conductive material and has an interdigital electrode structure; The method for preparing the flexible electrode layer comprises the following steps: S1, pasting tape on the polymer substrate film; S2, cutting the tape on the surface of the polymer substrate film with a laser beam, and tearing off the cut portion, so that the remaining tape forms a drop coating groove with an interdigitated electrode structure; S3, using a syringe to drip a conductive material solution in the dripping groove of the interdigitated electrode structure, and after the conductive material solution is completely dried, the remaining tape on the polymer substrate film is completely torn off, so that a flexible electrode layer is formed on the polymer substrate film; The polymer substrate is selected from at least one of polyethylene, polypropylene, fiber paper, leather, polyimide, polyethylene terephthalate, polytetrafluoroethylene, polycarbonate, polyurethane, silicone rubber, fluororubber, and thermoplastic elastomer. 2 . The flexible dielectric sensor according to claim 1 , wherein the flexible base layer is a polydimethylsiloxane-based base layer. 3 . 3. A flexible dielectric sensor according to claim 1, characterized in that the conductive material comprises at least one of graphene, carbon nanotubes, gold nanowires, silver nanowires, copper nanowires and metal nanoparticles. 4. A flexible dielectric sensor according to claim 1, characterized in that the method for preparing the conductive material solution consists of the following steps: A1. Pour ethylene glycol solution into a beaker, add polyvinyl pyrrolidone, and stir until the solution becomes clear to obtain a first solution; A2, grinding the prepared silver nitrate particles into powder, adding the powder to the mixed first solution, stirring magnetically, and then adding ferric chloride solution and stirring to obtain a second solution; A3, allowing the prepared second solution to react, and obtaining silver nanowires after the reaction is completed; A4, washing the silver nanowires in an acetone solution, and centrifuging and precipitating the silver nanowires, and then discarding the acetone solution after centrifugation to obtain precipitated silver nanowires; A5. Wash the precipitated silver nanowires for a second time with an ethanol solution, and then disperse the washed silver nanowires into an ethanol solution to obtain a conductive material solution. 5. A flexible dielectric sensor according to claim 4, characterized in that in the step A3, the ambient temperature of the second solution for static reaction is 100-120 degrees, and the reaction time is 11-13 hours. 6. A method for preparing a flexible dielectric sensor according to any one of claims 1 to 5, comprising the following steps: B1, pouring the prepared polydimethylsiloxane solution on the flexible electrode layer; B2. After the polydimethylsiloxane solution completely covers the flexible electrode layer, curing is performed to obtain a prototype of a flexible dielectric sensor; B3. Tear off the polymer substrate film at the bottom of the flexible dielectric sensor prototype to obtain a flexible dielectric sensor as a whole. 7. The method for preparing a flexible dielectric sensor according to claim 6, characterized in that in the step B2, the curing temperature is 70-90 degrees and the curing time is 20-40 minutes. 8. Use of a flexible dielectric sensor according to any one of claims 1 to 5 or a flexible dielectric sensor prepared by the preparation method according to any one of claims 6 to 7 in monitoring the curing of marine composite materials.