Underwater sound detection sensor based on friction nanometer power generation technology

Abstract

The invention discloses an underwater acoustic detection sensor based on a friction nanometer power generation technology, and belongs to the field of detectors. Comprising an upper backing material (1), an upper metal electrode (2), polymer particles (3), a spacing layer (4), a lower metal electrode (5), a lower backing material (6), a sound transmission sealing layer (7) and a reinforcing outer frame (8), the upper backing material (1), the upper metal electrode (2), the spacing layer (4), the lower metal electrode (5) and the lower backing material (6) are arranged and combined from top to bottom, the polymer particles (3) are filled in a cavity of the spacing layer (4), then the polymer particles (3) are wrapped by the sound transmission sealing layer (7), and the periphery of the polymer particles (3) is fixed by the reinforcing outer frame (8). TENG is innovatively used as a sensing mechanism, an external power supply is not needed for power supply, and electric signals can be spontaneously generated and output under ocean sound; underwater sound energy can be fully utilized, power is supplied to sensing equipment, the self-power-supply potential is achieved, dependence on a power source is reduced, and low-frequency sound in water can be detected.

Description

Technical field:

[0001] The present invention relates to the field of triboelectric nano-power generation technology, and mainly focuses on the design and application of ocean hydroacoustic detection sensors. Background technology:

[0002] With the continuous development of science and technology, the application of hydroacoustic technology in the fields of marine resource exploration, underwater communication, environmental monitoring, etc. has become increasingly important. Traditional hydrophones are mainly divided into several structures such as piezoelectric, piezoresistive and capacitive. They are widely used in hydroacoustic detection, but they also have certain disadvantages. The core component of piezoelectric hydrophones is piezoelectric ceramics, which generate a small voltage (millivolt level), and the low-frequency manufacturing size and weight are large. Therefore, in order to improve the sensitivity level of underwater low-frequency (50-1000Hz) sound detection, we invented a hydroacoustic detection sensor based on friction nano-power generation technology.

[0003] The friction nano-power generation technology generates a tiny current through the friction between two materials with different electronegativity, realizing the conversion of mechanical energy into electrical energy. With its advantages of high voltage, small size and low energy consumption, this technology has gradually been applied in the ocean and other fields, becoming a potential solution to the problems faced by traditional underwater acoustic detection systems.

[0004] Existing technical solutions: Since sound propagates over long distances and has low attenuation underwater, ocean acoustic detection has become one of the current research hotspots. In ocean acoustic detection, hydrophones are generally carried on marine facilities or equipment to work, and the hydrophones are designed to be optimized in the direction of high sensitivity, light weight, and small size.

[0005] There are few existing underwater sound detections based on friction nanogenerators, which are mainly based on the detection of sound in the air. Domestic patent CN104836473B discloses a generator and a sound sensor for collecting sound energy. Based on the characteristics of the Helmholtz resonance cavity, the sound passes through the Helmholtz resonance cavity so that the friction electric nanogenerator generates electricity under the action of the sound. However, in the process of collecting sound, the sound must pass through the resonance cavity to achieve effective collection. It has strong directionality and is not waterproof. In addition, domestic patent CN117589282A discloses a flexible substrate PVDF piezoelectric isotropic vector hydrophone and its assembly method. This patent mainly involves the technology of traditional hydrophones. The present invention has a reasonable structure and uses a flexible substrate combined with a piezoelectric film to have a lower resonance frequency, which can better meet the current low-frequency detection needs of underwater target detection.

[0006] As for the existing patents, the sound detection based on friction nano-power generation technology only studies the sound in the air, and there is no research on underwater sound detection, which is worthy of further study.

[0007] Insufficients of the existing technology: Domestic patent CN104836473B discloses a generator and a sound sensor for collecting sound energy. This sound energy collection generator and sound sensor can effectively detect sound signals in the air, but there are obvious deficiencies. First, it cannot be applied to underwater environments and lacks waterproof performance; second, the collection of sound is limited and can only capture the sound at the front end of the Helmholtz resonance cavity, and the overall directionality is poor.

[0008] Domestic patent CN117589282A mainly relates to a PVDF hydrophone with a flexible substrate. Although traditional PVDF hydrophones have strong impact resistance, they require a large-sized PVDF membrane to detect underwater low-frequency signals during the manufacturing process, which requires complex processing to ensure the uniformity of the PVDF membrane. Therefore, the manufacturing process is more complicated, which in turn increases the production cost.

[0009] In this context, this study aims to explore hydrophones based on triboelectric nanopower generation technology to achieve efficient and accurate detection of underwater low-frequency sounds. By combining the unique characteristics of triboelectric technology with the needs of underwater acoustic detection, it is expected to provide an advanced and reliable solution for fields such as marine science, underwater detection and communications. This innovative research will advance underwater acoustic technology and provide new possibilities for underwater environmental research and applications. Summary of the invention:

[0010] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0011] A water acoustic detection sensor based on friction nano-power generation technology, characterized in that it comprises an upper backing material (1), an upper metal electrode (2), polymer particles (3), a spacer layer (4), a lower metal electrode (5), a lower backing material (6), a sound-transmitting sealing layer (7), and a reinforcement outer frame (8); the upper backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are stacked together in sequence from top to bottom; the backing material (1), the upper metal electrode (2), the lower metal electrode (5), and the lower backing material (6) are all plate-like structures, and the specific plate-like structure has an extension strip (11) extending in the same plane on the side; the upper backing material (1) and the upper metal electrode (2) are stacked together up and down, and the extension strips of the upper backing material (1) and the upper metal electrode (2) are synchronously stacked as an upper connecting electrode (9); the lower metal electrode (5) and the lower backing material (6) are stacked together up and down, The lower metal electrode (5) and the extended strip of the lower backing material (6) are synchronously stacked as the lower connecting electrode (10); the upper metal electrode (2) and the lower metal electrode (5) are connected by a spacer layer (4), the spacer layer (4) is a hollow plate-shaped frame around the edges, the spacer layer (4) forms a cavity between the upper metal electrode (2) and the lower metal electrode (5), and the polymer particles (3) are filled in the cavity; the backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are wrapped in a sound-transmitting sealing layer (7) and a reinforcement outer frame (8), and the sides of the stacked upper backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are surrounded by a reinforcement outer frame (8); the corresponding upper connecting electrode (9) and the lower connecting electrode (10) extend out of the sound-transmitting sealing layer (7) and the reinforcement outer frame (8).

[0012] The upper backing material (1) and the lower backing material (6) are as thin as possible while ensuring their own mechanical strength, and preferably use acrylic plates, so that the effective vibration thickness of the backing material is 0.1 mm, and the effective vibration area is selected according to needs, such as 5×5 cm;

[0013] The upper metal electrode (2) and the lower metal electrode (5) are pasted on the corresponding backing materials. The electrode thickness is as thin as possible. Preferably, an aluminum foil tape with a thickness of 20 μm is pasted on the acrylic plate as the electrode layer.

[0014] The sound-transmitting sealing layer (7) is a rubber layer with a thickness of 1-2 mm. The sound-transmitting sealing layer is obtained by an in-situ casting preparation method.

[0015] The spacer layer (4) is made of sponge paper, which has a certain flexibility, and the thickness of the cavity spacer layer is 1.0-2.0 mm;

[0016] The polymer particles (3) are microsphere particles; further, PTFE particles are used, the particle size is less than 1 mm, and the average particle size is 0.2-0.5 mm. The plurality of polymer particles (3) have gaps in the cavity, and the polymer particles (3) in the cavity can vibrate in the cavity (especially vibrate in the direction of the upper metal electrode and the lower metal electrode), and can also be arranged in an array (for example, arranged in one layer or several layers) during the vibration process.

[0017] Furthermore, the upper metal electrode (2) and the lower metal electrode (5) are replaced with corresponding organic polymer films with electrodes (the electrodes may be peripheral, etc.), and the polymer particles (3) are replaced with metal particles.

[0018] The present invention discloses an underwater acoustic detection sensor based on friction nano-power generation technology for detecting the frequency of underwater sound, and for detecting the frequency of underwater low-frequency (50-1000HZ) sound. When used in a conventional manner, after the underwater sound acts on the sensor, the sensor can generate a current / voltage signal of a certain frequency, and this frequency is basically consistent with the frequency of the sound received in the water.

[0019] The sensor can work in the horizontal, vertical or at a certain angle to the horizontal plane. The horizontal, vertical or at a certain angle to the horizontal plane refers to the board surface in the direction of the upper backing material (1) being horizontal, vertical or at a certain angle to the horizontal plane.

[0020] Advantages of the present invention:

[0021] 1. In order to make the hydrophone have good pressure resistance, the overall structural design first uses rubber for external packaging, which has a certain pressure resistance, and designs a structure in which microsphere particles fill the cavity. At the same time, since the interior is filled with microspheres, it also has a certain pressure resistance. The sound waves can still cause the internal thin plate (metal electrode and backing material) to vibrate through vibration, and fully contact with the microsphere particles filled inside;

[0022] 2. With the purpose of efficiently detecting underwater sounds, in terms of working principle, the TENG part replaces the traditional membrane structure that collects vibrations with a contact separation between powder particles and membrane vibrations, reducing the interference of the resonant frequencies between the two films;

[0023] 3. To improve the sensitivity of the hydrophone based on triboelectric nanopower generation technology, the signal sensing part of the TENG is structured, and two materials with large electronegativity differences are selected as friction materials. It is not limited to using polymer particles and metal electrodes, but can also be metal particles and organic polymer films with electrodes.

[0024] 4. In order to make the hydrophone have good sound permeability and sealing performance underwater, the sealing layer is encapsulated with rubber, and the thickness of the rubber layer after encapsulation is strictly controlled to minimize the loss of underwater sound through the rubber layer;

[0025] 5. To reduce the self-noise signal, the test equipment is placed in a Faraday cage during the test, or a copper mesh is used to separate the HP-TENG from the outside world, and the test equipment is grounded to effectively reduce noise interference;

[0026] 6. With the goal of improving the signal-to-noise ratio of the final hydrophone, the backing material (acrylic board) selected in the detection of this structure is as thin as possible while ensuring its own mechanical strength and fitting the electrode. The effective vibration area of ​​the backing material in the final structure is 5×5cm, and the effective vibration thickness is 0.1mm; the thickness of the electrode pasted on the acrylic board is as thin as possible, and an aluminum foil tape with a thickness of 20μm is selected to be pasted on the acrylic board as the electrode layer; in this structure, the thickness of the sealing layer rubber is controlled to be about 1-2mm; sponge paper is selected as the cavity spacer layer, which has a certain flexibility, and the thickness of the cavity spacer layer is 1.5mm; the particle size of the PTFE particles filled inside is less than 1mm, and the average particle size is about 0.2-0.5mm. Description of the drawings:

[0027] Figure 1 Schematic diagram of the explosion structure of the TENG hydrophone; upper backing material (1), upper metal electrode (2), polymer particles (3), spacer layer (4), lower metal electrode (5), lower backing material (6), sound-transmitting sealing layer (7), reinforced outer frame (8)

[0028] Figure 2 Schematic diagram of the overall structure of the TENG hydrophone; acoustically transparent sealing layer (7), reinforcement outer frame (8), upper connecting electrode (9), lower connecting electrode (10)

[0029] Figure 3 Schematic diagram of the structure of the backing material with electrodes attached;

[0030] Figure 4 Schematic diagram of the principle of friction power generation;

[0031] Figure 5 Schematic diagram of the comsol friction power generation principle;

[0032] Figure 6 PTFE particle size diagram under metallographic microscope;

[0033] Figure 7 Current signal test of TENG hydrophone in an ultrasonic water pool with a power of 400W and a frequency of 40KHz; (a) horizontal placement, (b) vertical placement

[0034] Figure 8 Voltage signal test of TENG hydrophone under underwater speaker in a pool. Specific implementation method:

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods, but is not limited to the following embodiments.

[0036] Example 1

[0037] (1) Material selection:

[0038] The sound-transmitting sealing layer 7 is made of silicone rubber; in the power generation structure of friction power generation, the two friction materials are respectively metal electrodes and polymer powder particles, wherein the metal electrode tape is directly pasted on the acrylic plate, and the metal (aluminum) tape with a thickness of 20 μm is selected, and the particle size of the polymer powder particles is about 200 to 500 μm; the inner cavity uses sponge paper with a thickness of 1.5 mm; the backing material layer is an acrylic plate with the smallest sound attenuation, and the thickness is selected to be 0.1 mm;

[0039] (2) Production process:

[0040] Internal TENG structure: First, use a laser cutting machine to cut a 0.1mm thick acrylic sheet into a knife-like structure. The handle corresponds to the extension bar. See the attached figure for a detailed schematic diagram. Figure 3 As shown, the upper square size is 6cm×6cm, and the handle portion extending from the bottom is a rectangle of 3×2cm. Use 20μm thick metal tape to cover the cut acrylic plate as the electrode, and lead wires from the electrodes (2, 5) at the handle. Use metal tape to directly stick the wires on the electrodes.

[0041] Next, use scissors to cut 1.5mm thick sponge paper to form a cavity structure with an outer circle length of 6cm and an inner circle length of 5cm as a spacer layer. Double-sided tape is attached to both sides to facilitate adhesion to the acrylic plate with electrodes. A certain amount of 200-500μm polymer powder particles are filled inside the spacer layer as a negative friction material.

[0042] Finally, another acrylic plate with electrodes attached was pasted onto the spacer layer to complete the internal TENG fabrication.

[0043] External packaging: First, use a 3D printer to print a frame (8) for subsequent pouring of silicone rubber. For external packaging, use silicone rubber to mix prepolymer A and curing agent B in a ratio of 10:1. After stirring evenly, vacuum evacuate to remove bubbles. Pour the mixture evenly into the frame with a thickness of about 1 mm. After 6 hours, the silicone rubber in the frame solidifies and then the internal TENG is placed.

[0044] Next, pour the mixed silicone rubber liquid into the frame to cover the entire internal TENG structure. The overall silicone rubber wrapping thickness is controlled to be about 1mm. After 6 hours, the entire silicone rubber is completely solidified and the hydrophone is completed. Subsequently, the sound field test is carried out and the hydrophone is placed in a pool for testing.

[0045] (3) Working principle:

[0046] The structure can work normally when it is horizontal, vertical or tilted at a certain angle. No matter what state the structure is in, its internal particles will maintain a certain arrangement state and maintain basic contact with the surfaces of electrodes 2 and 5. Because underwater sound waves are continuously vibrating, when one side of the structure receives underwater sound waves, the sound waves pass through the sealed sound-permeable layer 7 and reach the backing materials 1 and 6 with electrodes. The vibration causes them to vibrate and is further transmitted to the internal particles, resulting in relative movement between the particles and the electrodes. This movement will cause the separation and redistribution of charges, thereby generating electrical signals and realizing the detection of underwater sounds. This design ensures that the structure can work efficiently and stably at various angles and environments.

[0047] Taking the horizontal placement of the hydrophone as an example, the specific working principle diagram is shown in the attached figure. Figure 4 As shown. In the initial state of the TENG structure, the polymer particles and the metal, such as the aluminum electrode, are stationary. When the thin plate with the Al electrode below is vibrated by the acoustic signal, the internal PTFE particles begin to vibrate, resulting in the first separation from the Al electrode below. Due to electrostatic induction and friction electrification effects, the lower Al electrode carries a positive charge and the PTFE ball carries a negative charge. At this time, the upper Al electrode has no charge, and a potential difference is formed between the two electrode plates, causing the current to flow from the lower electrode plate to the upper electrode plate. When the ball moves to the center of the two electrodes, the current reaches its maximum value; as it continues to vibrate upward, the current gradually decreases; at the maximum vibration displacement, the ball contacts the upper electrode plate and the current is the minimum. Similarly, when the ball moves from top to bottom, the current direction is opposite, forming a complete power generation cycle. Finally, we perform finite element simulations on the potential changes of TENG under different conditions, such as Figure 5 As shown, the potential distribution results are consistent with the predicted results.

[0048] in Figure 6 Shown is a picture of the used PTFE particles under a metallographic microscope.

[0049] (4) Test results:

[0050] The following test equipment is mainly used: underwater speaker, power amplifier, signal generator, 6514 electrometer, sound-absorbing sponge, test water tank, ultrasonic water tank;

[0051] Secondly, the structure was placed in an ultrasonic water tank with a size of 35*30*25 cm for testing, the power was set to 400 W and the ultrasonic frequency was set to 40 kHz, and the structure was placed at different angles for testing.

[0052] Figure 7 (a) and (b) are the current signals of the structure under vertical and vertical tests in a water tank, respectively. It can be seen that the performance of the structure in the horizontal state is better than that in the vertical state. The difference between the two may be related to the design of the TENG structure.

[0053] Finally, the structure was placed in a water tank for experimental testing. The specific steps were as follows: the TENG was placed horizontally at the bottom of the water tank, and an underwater speaker was used 15 cm above it. The underwater speaker was controlled by a signal amplifier to emit a certain decibel sound wave of 50-1000 Hz. The sound wave propagated through the water and when it came into contact with the sealing layer (2) of the TENG, it was transmitted to the backing material (3) through it, further causing the internal particles to vibrate and generate electrical signals. Figure 8 This is the voltage signal generated by TENG after receiving sound waves. The inset is the voltage signal generated by TENG under 150Hz sound waves, indicating that this structure can also identify the frequency of sound waves.

[0054] Further verification of the sound wave frequency: We use a mobile phone APP to control the signal amplifier, and the signal amplifier controls the underwater speaker. When the mobile phone APP outputs a 150Hz frequency signal, the underwater speaker will emit a 150Hz frequency sound through the signal amplifier. At this time, we detect the sound through the TENG hydrophone, and a 150Hz current / voltage signal will also be generated. Similarly, if a 500Hz signal is input, a 500Hz electrical signal will also be output.

[0055] Advantages of the present invention:

[0056] Self-driving: New self-driving sensing principle - using TENG technology to directly power the sensing structure

[0057] The innovative proposal uses TENG as a sensing mechanism, which does not require external power supply and can spontaneously generate and output electrical signals under the sound of the ocean. It can fully utilize underwater sound energy to power the sensing equipment, has the potential for self-powering, and reduces dependence on power supply.

[0058] 1. Excellent sensitivity:

[0059] First, the present invention adopts the principle of friction nano-power generation and can produce high voltage output characteristics. The HP-TENG structure generates 1200mV voltage and 89nA current under 150dB sound pressure level and 150Hz frequency underwater sound, which has high sensitivity, making it perform well in applications such as underwater sound detection.

[0060] Second, the flat-plate design of the TENG structure can effectively increase the receiving area, making the underwater sound detection sensor highly sensitive and able to detect underwater sounds in a wide frequency band, including low-frequency (50-1000Hz) and high-frequency (40kW ultrasonic) sounds.

[0061] 2. Strong adaptability:

[0062] Through the ultrasonic water tank test in horizontal and vertical states, the adaptability of TENG in different directions and environments is demonstrated in different placements. In addition, the test of the electrical signal generated by the underwater speaker and TENG at different angles was also tested, and there was a certain signal. Therefore, the TENG of this structure has strong adaptability underwater.

[0063] 3. Good directivity:

[0064] Since the structure of the present invention is a sandwich structure with symmetrical internal components, the present invention can respectively receive the front and rear propagating underwater sound and has excellent "8"-shaped directivity.

[0065] 4. Simple production process:

[0066] pass Figure 1 An acrylic plate with electrodes attached to the upper part is shown. The manufacturing process is relatively simple and suitable for mass production and wide application.

[0067] This embodiment provides an actual production example based on, and each part of an embodiment of the present invention is specifically described below.

[0068] 1. Preparation of sealing layer: Figure 2 As shown in the structural diagram, the outermost layer uses silicone rubber as a sealing layer. The silicone rubber mold is accurately printed by a light-curing printer. The specific structure is as follows: Figure 2 As shown in the 8 reinforcement frame.

[0069] 2. Assembly of friction power generation structure: Figure 1 As shown in the figure, the key components of the triboelectric structure include acrylic plate, negative friction material PTFE particles and metal aluminum electrodes, all of which are purchased directly from the market. The grooves and other structures on the acrylic plate are completed by laser etching, and the Al electrode is cut into corresponding shapes and pasted on the acrylic plate. In order to improve the conductivity of the aluminum electrode, a certain amount of sodium hydroxide solution is applied to the surface of the purchased aluminum tape to remove the aluminum oxide on its surface during the experiment to remove the oxide layer.

[0070] 3. Spacer layer installation: The inner cavity (4) of the sponge structure is cut into a specific structure (outer circle side length 6 cm, inner circle side length 5 cm) with scissors according to the design requirements, and double-sided tape is pasted on both sides to firmly fix it on the acrylic board.

[0071] 4. Negative friction material filling: A certain amount of 200-500 μm PTFE (3) powder particles is filled inside the sponge structure as negative friction material.

[0072] 5. A number of wires can be purchased directly from the market and are respectively led out from the upper and lower aluminum electrodes (9, 10) to eventually form a pair of electrodes. At the same time, the positive and negative electrodes are connected to detect the electrical signal generated by the output friction power generation module.

[0073] Through the above steps, the hydrophone in the embodiment is assembled and has the characteristics of waterproofness, stability and efficient energy conversion. This implementation example of the best mode shows excellent performance and feasibility in practical applications.

Claims

1. A water acoustic detection sensor based on friction nano-power generation technology, characterized in that: The invention comprises an upper backing material (1), an upper metal electrode (2), polymer particles (3), a spacer layer (4), a lower metal electrode (5), a lower backing material (6), a sound-transmitting sealing layer (7), and a reinforcing outer frame (8); the upper backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are stacked together in sequence from top to bottom; the backing material (1), the upper metal electrode (2), the lower metal electrode (5), and the lower backing material (6) are all plate-like structures, and the specific plate-like structures have extension strips (11) extending in the same plane on the side edges; the upper backing material (1) and the upper metal electrode (2) are stacked together from top to bottom, and the extension strips of the upper backing material (1) and the upper metal electrode (2) are synchronously stacked as an upper connecting electrode (9); the lower metal electrode (5) and the lower backing material (6) are stacked together from top to bottom, and the lower metal electrode (5) and the lower backing material The extended strips of (6) are synchronously stacked as the lower connecting electrode (10); the upper metal electrode (2) and the lower metal electrode (5) are connected by a spacer layer (4), the spacer layer (4) is a hollow plate-shaped frame around the edges, the spacer layer (4) forms a cavity between the upper metal electrode (2) and the lower metal electrode (5), and the polymer particles (3) are filled in the cavity; the backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are wrapped in a sound-transmitting sealing layer (7) and a reinforcing outer frame (8), and the sides of the stacked upper backing material (1), the upper metal electrode (2), the polymer particles (3), the spacer layer (4), the lower metal electrode (5), and the lower backing material (6) are surrounded by a reinforcing outer frame (8); the corresponding upper connecting electrode (9) and the lower connecting electrode (10) extend out of the sound-transmitting sealing layer (7) and the reinforcing outer frame (8).

2. The underwater acoustic detection sensor based on friction nano-power generation technology according to claim 1 is characterized in that: The upper backing material (1) and the lower backing material (6) are as thin as possible while ensuring their own mechanical strength, and preferably use acrylic plates so that their effective vibration thickness as backing materials is 0.1 mm; The upper metal electrode (2) and the lower metal electrode (5) are pasted on the corresponding backing materials, and the thickness of the electrodes is as thin as possible; The sound-transmitting sealing layer (7) is a rubber layer with a thickness of 1-2 mm; the sound-transmitting sealing layer is obtained by an in-situ casting method; The spacer layer (4) is made of sponge paper, and the thickness of the cavity spacer layer is 1.0-2.0 mm; The polymer particles (3) are microsphere particles; further, PTFE particles are used, the particle size is less than 1 mm, and the average particle size is 0.2-0.5 mm; multiple polymer particles (3) have gaps in the cavity, and the polymer particles (3) in the cavity can vibrate in the cavity.

3. A water acoustic detection sensor based on friction nano-power generation technology according to claim 2, characterized in that: Aluminum foil tape with a thickness of 20 μm was selected and pasted on the acrylic plate as the electrode layer.

4. A water acoustic detection sensor based on friction nano power generation technology according to claim 1 or 2, characterized in that: The upper metal electrode (2) and the lower metal electrode (5) are replaced by corresponding organic polymer films with electrodes, and the polymer particles (3) are replaced by metal particles.

5. The underwater acoustic detection sensor based on friction nano power generation technology described in any one of claims 1 to 4 is used for detecting underwater sound.

6. The use according to claim 5, for detecting the frequency of underwater low-frequency 50-1000HZ sound.

7. According to the application described in claim 5 or 6, when in use, after the underwater sound acts on the sensor, the sensor can generate a current / voltage signal of a certain frequency, and this frequency is basically consistent with the frequency of the sound received in the water.

8. According to the application described in claim 5 or 6, the sensor can work in the horizontal, vertical or inclined at a certain angle to the horizontal plane, and the horizontal, vertical or inclined at a certain angle to the horizontal plane refers to the board surface in the direction of the upper backing material (1) being horizontal, vertical or inclined at a certain angle to the horizontal plane.

9. According to the application described in claim 5 or 6, the underwater sound propagating in front and behind the sensor can be received and detected, and has excellent "8"-shaped directivity.

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