Preparation method of flexible triboelectric acoustic sensor for monitoring diseases

Abstract

The invention discloses a preparation method of a triboelectric acoustic sensor. The preparation method comprises the following steps: washing animal leather with ethanol and deionized water respectively, and drying the animal leather; then PVDF is mixed with nanoparticles and then dissolved in an organic solvent, stirring is conducted for 4-12 h at the temperature of 40-70 DEG C till complete dissolution, and the obtained solution is subjected to electrostatic spinning to obtain a highly-polarized composite film; the dried animal leather is used as a positive friction layer of the sensor, a conductive material is used for plating a conductive layer on the surface, the obtained electrostatic spinning film is used as a negative friction layer, the friction layers are adhered through conductive glue, and the triboelectric acoustic sensor is obtained. The sensor is suitable for detecting heart sound, lung sound, intestine sound and other internal sound signals of the human body, can convert the picked weak sound signals into electric signals, and has guiding significance in early diagnosis of heart diseases, pneumonia and other diseases in the fields of biomedicine and the like.

Description

Technical Field

[0001] This invention relates to the technical field of acoustic detection inside the human body, and in particular to a method for preparing a flexible triboacoustic sensor for monitoring diseases. Background Technology

[0002] Acoustic sensors are of great significance in human disease and environmental monitoring, and are currently widely used in industry, medical devices, and human-computer interaction. Sound is generated by the vibration of objects and is the most common mechanical wave. In the medical field, professionals often use auscultation to initially monitor abnormalities inside the body. Since 1800, due to its simplicity and non-invasiveness, auscultation using an acoustic stethoscope has been the most routine method for determining a patient's physiological state. However, traditional stethoscopes require doctors to have excellent hearing and judgment. Therefore, electronic stethoscopes were developed to amplify small signals to a reasonable level and reduce the impact of environmental noise. Traditional piezoelectric acoustic sensors rely on piezoelectric materials or complex circuits, which have problems such as poor flexibility and insufficient sensitivity. Moreover, existing triboelectric acoustic sensors mostly use synthetic polymer materials, which lack biocompatibility and environmental friendliness. This invention uses leather with natural micro-nano-scale surface texture as the positive friction layer of the triboelectric acoustic sensor and combines it with a PVDF composite film that has both piezoelectric and triboelectric properties to form a flexible triboelectric acoustic sensor for disease monitoring. Summary of the Invention

[0003] This invention provides a method for preparing a flexible triboacoustic sensor for monitoring diseases, which solves the problems of insufficient biocompatibility and environmental friendliness of existing triboacoustic sensors.

[0004] This invention provides a method for fabricating a triboelectric acoustic sensor, comprising the following steps:

[0005] (1) The animal leather was washed three times each with ethanol and deionized water, and then dried in an oven.

[0006] (2) Apply a conductive layer to the dried leather surface and then dry it in an oven at 80°C.

[0007] (3) Place nanoparticles and PVDF in an organic solvent and stir at 40-70℃ for 4-12h until completely dissolved. The resulting solution is then electrospun to obtain a highly polarized composite film.

[0008] (4) The sheepskin coated with electrodes is used as the positive friction layer of the sensor, and the composite film is used as the negative friction layer. The friction layers are bonded together with conductive adhesive to obtain the triboacoustic sensor.

[0009] Preferably, the leather is treated with ethanol and deionized water to remove natural oils and water-soluble impurities from the surface.

[0010] Preferably, the animal leather is one of sheep leather, cow leather, horse leather, or pig leather.

[0011] Preferably, the conductive material is at least one of silver paste, copper paste, carbon paste, carbon nanotube paste, PEDOT:PSS, and AgNWs.

[0012] Preferably, the method for preparing the electrode is one of screen printing, spin coating, or spray coating.

[0013] Preferably, the nanoparticles are at least one of BaTiO3, SrTiO3, TiO3, ZnO, CNT, and PZT.

[0014] Preferably, the organic solvent is at least one of N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and acetone.

[0015] Preferably, animal leather is used as the positive friction layer and PVDF composite film is used as the negative friction layer. The two are used in a contact-separation mode to form a triboacoustic sensor.

[0016] A method for fabricating a flexible triboacoustic sensor for monitoring diseases reveals that the sensor converts acoustic signals into electrical signals, and monitors internal acoustic signals of the human body through the generated electrical signals.

[0017] Beneficial effects:

[0018] The flexible triboacoustic sensor prepared in this invention first uses leather as the positive friction layer, replacing traditional polymer synthetic materials and reducing resource consumption. Simultaneously, animal leather is biodegradable, reducing environmental pollution. Second, the PVDF composite film, serving as the negative friction layer, is prepared using electrospinning technology and then assembled into the flexible triboacoustic sensor using conductive adhesive, simplifying the process. The overall thickness of the sensor is less than 1 mm, and it perfectly conforms to the curved surface of the human body, avoiding skin discomfort caused by prolonged wear. Finally, the flexible triboacoustic sensor requires no external power supply, can drive low-power circuits, and can achieve a "battery-free" design in wearable devices. Attached Figure Description

[0019] Figure 1 This is a diagram of the layered structure of the sensor, where 1 is leather, 2 is conductive adhesive, and 3 is electrospun film.

[0020] Figure 2 SEM image of leather surface. Detailed Implementation

[0021] Example 1:

[0022] The method for fabricating the flexible triboacoustic sensor of the present invention is described in detail below:

[0023] Select sheep leather with a thickness of approximately 0.5 mm, soak the leather in a 70% ethanol solution, and agitate it at a constant temperature of 60°C for 30 minutes to dissolve surface grease and organic contaminants; then rinse it repeatedly with deionized water until neutral (pH≈7) to remove residual ethanol and water-soluble impurities, and place it in a vacuum drying oven at 60°C for 4 hours to ensure a moisture content of <2%.

[0024] Take 1g of PVDF powder (molecular weight 300,000-500,000) and 0.05g of barium titanate powder and dissolve them in V DMF V 丙酮 The solution was mixed with a ratio of 8:2 and magnetically stirred at 60℃ for 8 hours until a transparent solution was formed. Then, a PVDF composite membrane was prepared by electrospinning. Specifically, the solution was placed in a syringe, the electrospinning apparatus voltage was set to 20kV, the injection rate to 0.8mL / h, and the receiving distance to 15cm. During the spinning process, a high-voltage electric field induced the directional alignment of the PVDF molecular chains, promoting the formation of the β phase.

[0025] Silver paste is applied to the leather surface as a conductive layer using screen printing technology. The surface is then annealed at 80°C for 10 minutes to remove the solvent and cure the conductive layer.

[0026] The PVDF composite film (negative friction layer) and the leather with a conductive coating (positive friction layer) were cut into pieces with dimensions of 2×2 cm. 2 The cube-shaped structure uses conductive carbon cloth to bond the positive and negative friction layers together. Then, leads are connected to the conductive layers of the leather and PVDF film, which are then connected to the signal acquisition circuit.

[0027] Example 2:

[0028] The method for fabricating the flexible triboacoustic sensor of the present invention is described in detail below:

[0029] Select cowhide with a thickness of about 0.5mm, soak the leather in a 70% ethanol solution, and shake it at a constant temperature of 60℃ for 30 minutes to dissolve surface grease and organic contaminants. Rinse it repeatedly with deionized water until neutral (pH≈7) to remove residual ethanol and water-soluble impurities. Place it in a vacuum drying oven and dry it at 60℃ for 4 hours to ensure that the moisture content is <2%.

[0030] Take 1g of PVDF powder (molecular weight 300,000-500,000) and 0.05g of titanium dioxide nanoparticles, and dissolve them in V DMF V 丙酮The solution was mixed at a ratio of 7:3, then sonicated for 30 minutes and magnetically stirred at 60°C for 8 hours until completely dissolved. A PVDF composite membrane was then prepared by electrospinning. Specifically, the solution was placed in a syringe, the electrospinning apparatus voltage was set to 18kV, the injection rate to 1.0mL / h, and the receiving distance to 15cm. During the spinning process, a high-voltage electric field induced the directional alignment of the PVDF molecular chains, promoting the formation of the β phase.

[0031] Silver paste is applied to the leather surface using screen printing technology as a conductive layer. The surface is then annealed at 80°C for 10 minutes to remove the solvent and cure the conductive layer.

[0032] The PVDF composite film (negative friction layer) and the leather with a conductive coating (positive friction layer) were cut into pieces with dimensions of 2×2 cm. 2 The cube-shaped structure uses conductive carbon cloth to bond the positive and negative friction layers together. Leads are connected to the conductive layers of the leather and PVDF film, which are then connected to the signal acquisition circuit.

[0033] The above detailed description of the implementation is provided only as an example and is not intended to limit the diverse implementation schemes of the present invention. Several modifications and improvements can be made without departing from the inventive concept of the present invention, and these should also be considered within the protection scope of the present invention.

Claims

1. A method for preparing a flexible triboacoustic sensor for monitoring diseases, characterized in that: (1) The animal leather was washed three times with ethanol and three times with deionized water, and then dried in a 60°C oven for 4 hours to obtain dried leather. (2) A layer of conductive material is plated on the dried leather surface, and then it is placed in an 80°C oven to dry for 10 minutes to obtain leather plated with electrodes. (3) Place nanoparticles and PVDF in 5 mL of organic solvent and stir at 40-70 °C for 4-12 h until completely dissolved. Then obtain a highly polarized composite film by electrospinning. (4) The leather coated with electrodes is used as the positive friction layer of the sensor, and the composite film is used as the negative friction layer. The friction layers are bonded together with conductive adhesive to obtain a triboacoustic sensor.

2. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: The animal leather mentioned is one of sheep leather, cow leather, horse leather, or pig leather.

3. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: The conductive material is one of silver paste, copper paste, carbon paste, carbon nanotube paste, PEDOT:PSS, and AgNWs.

4. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: The method for preparing the electrode is one of screen printing, spin coating, or spray coating.

5. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: The nanoparticles mentioned are BaTiO3 nanoparticles.

6. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: The organic solvent is a mixture of N,N-dimethylformamide (DMF) and acetone in a volume ratio of 7:

3.

7. The method for preparing a triboacoustic sensor according to claim 1, characterized in that: Animal leather is used as the positive friction layer, and PVDF composite film is used as the negative friction layer. The two are used in a contact-separation mode to form a triboacoustic sensor.

8. A method for detecting heartbeat, characterized in that: The aforementioned sensor converts acoustic signals into electrical signals, and uses the generated electrical signals to monitor acoustic signals inside the human body.

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