A polyimide nanofiber-based piezoelectric sensor

Abstract

The utility model discloses a kind of piezoelectric sensor based on polyimide nanofiber, sensor includes: polyimide nanofiber layer, the layer has piezoelectric performance, can respond to external mechanical stress, pressure or vibration change and produce electric signal;Electrode layer is set to the both ends of polyimide nanofiber layer, electrode layer is used to collect the electric signal generated by polyimide nanofiber layer;Substrate, substrate is used to support polyimide nanofiber layer and electrode layer, and provide mechanical support;Protective layer, cover electrode layer and polyimide nanofiber layer;Signal processing unit is used to process the electric signal generated by polyimide nanofiber layer and output available sensing signal, the utility model relates to sensor technical field, the piezoelectric sensor based on polyimide nanofiber, high sensitivity and reliability: the piezoelectric performance of polyimide nanofiber layer is excellent, can produce enough electric signal under weak external pressure or vibration effect.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, specifically to a piezoelectric sensor based on polyimide nanofibers. Background Technology

[0002] With the continuous development of flexible electronics technology, flexible piezoelectric sensors are increasingly widely used in wearable devices, medical monitoring, smart homes, and automotive electronics due to their high sensitivity, portability, and deformability. Most existing piezoelectric sensors use hard piezoelectric materials, such as lead zirconate titanate (PZT) or polymer piezoelectric materials. While these materials have good piezoelectric properties, they have certain limitations in applications with specific requirements for flexibility and lightweight design.

[0003] Polyimide (PI) is a polymer material with excellent flexibility, high temperature resistance, and chemical stability, and has been widely used in the electronics field in recent years. Polyimide nanofibers prepared by electrospinning technology can maintain the excellent properties of polyimide while also providing good piezoelectric properties, thus becoming a research hotspot for novel piezoelectric materials. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a piezoelectric sensor based on polyimide nanofibers, which solves the existing technical problems.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a piezoelectric sensor based on polyimide nanofibers, the sensor comprising:

[0006] The polyimide nanofiber layer has piezoelectric properties and can generate electrical signals in response to external mechanical stress, pressure or vibration changes.

[0007] An electrode layer is disposed at both ends of the polyimide nanofiber layer, and the electrode layer is used to collect electrical signals generated by the polyimide nanofiber layer.

[0008] A substrate, which supports the polyimide nanofiber layer and the electrode layer and provides mechanical support;

[0009] A protective layer covers the electrode layer and the polyimide nanofiber layer. The protective layer has the properties of resisting mechanical wear and chemical corrosion to enhance the service life of the sensor.

[0010] The signal processing unit, connected to the electrode layer, is used to process the electrical signals generated by the polyimide nanofiber layer and output usable sensing signals.

[0011] Preferably, the polyimide nanofiber layer is a nanofiber layer prepared by electrospinning technology, and the arrangement direction of the nanofiber layer is at a certain angle to the direction of external mechanical stress, so as to enhance the response sensitivity of the sensor.

[0012] Preferably, the electrode layer is a conductive material selected from aluminum, copper, silver, gold, graphene or their alloys, and the electrode layer is connected to the polyimide nanofiber layer by evaporation, sputtering or printing.

[0013] Preferably, the substrate is a flexible material selected from polyimide film, polyester film, polyester resin or glass fiber. The flexible substrate can be bent or stretched to meet the needs of wearable devices or flexible electronic products.

[0014] Preferably, the protective layer is a transparent polyurethane film or a polyimide film, and the thickness of the protective layer is 0.1 μm to 10 μm, which is used to prevent physical damage to the sensor from the external environment and to ensure the stable operation of the sensor under harsh conditions.

[0015] Preferably, the signal processing unit includes an amplifier circuit, a filter circuit, and an analog-to-digital converter to enhance the stability and reliability of the signal and convert the analog signal generated by the sensor into a digital signal output.

[0016] Preferably, the sensor operates in the frequency range of 10Hz to 10kHz and is suitable for detecting vibration, pressure, impact or acoustic signals.

[0017] Preferably, the sensor has a piezoelectric constant greater than 10 pC / N, and is able to generate a sufficient electrical signal under weak external pressure or vibration signals.

[0018] Preferably, the sensor is used to detect motion in smart wearable devices, human physiological signals, robot vibration signals, pressure changes in automotive electronic devices, or mechanical signals in medical monitoring devices.

[0019] Beneficial effects

[0020] This invention provides a piezoelectric sensor based on polyimide nanofibers. It offers the following advantages: This piezoelectric sensor based on polyimide nanofibers exhibits high sensitivity and reliability; the polyimide nanofiber layer possesses excellent piezoelectric properties, enabling it to generate sufficient electrical signals under weak external pressure or vibration.

[0021] Flexibility and scalability: Utilizing a flexible substrate, it can be adapted to applications such as wearable devices, smart homes, and flexible electronics;

[0022] Durability: The protective layer enhances the sensor's wear and corrosion resistance, extending its service life;

[0023] Wide range of applications: Applicable to a variety of fields, including smart wearables, robots, automotive electronics, and medical monitoring equipment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of this utility model.

[0025] In the figure: 1. Substrate; 2. Protective layer; 3. Electrode layer; 4. Polyimide nanofiber layer; 5. Signal processing unit. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Those skilled in the art should connect all electrical components and their compatible power supplies to each other using wires, and select appropriate controllers according to actual conditions to meet control requirements. The specific connection and control sequence should refer to the working sequence of each electrical component in the following working principle to complete the electrical connection. The detailed connection methods are well-known technologies in the art. The following mainly introduces the working principle and process, and will not explain the electrical control.

[0028] Please see Figure 1 This utility model provides a technical solution:

[0029] Example 1: Flexible piezoelectric sensor based on polyimide nanofibers

[0030] This embodiment provides a flexible piezoelectric sensor based on polyimide (PI) nanofibers, the structure of which includes a polyimide nanofiber layer, an electrode layer, a flexible substrate, a protective layer, and a signal processing unit.

[0031] 1. Polyimide nanofiber layer:

[0032] In this embodiment, the polyimide nanofiber layer is prepared by electrospinning technology. During the preparation process, polyimide resin (such as PI-2545) is dissolved in N,N-dimethylformamide (DMF) solvent to prepare a 15% solution.

[0033] The electrospinning process uses a DC voltage of 18kV, an electrospinning distance of 15cm, and a collection rate of 0.5mL / h to obtain polyimide nanofibers with a diameter of 200nm.

[0034] The polyimide nanofiber layer is 2 μm thick, with a loose interlayer structure, exhibiting good flexibility and piezoelectric properties.

[0035] 2. Electrode layer:

[0036] In this embodiment, aluminum (Al) is selected as the electrode material, and an aluminum electrode of about 200 nm is deposited at both ends of the polyimide nanofiber layer using magnetron sputtering.

[0037] The aluminum electrode is formed by photolithography, with an electrode area of ​​10mm×10mm, ensuring good contact between the electrode and the nanofiber layer, which can effectively collect electrical signals.

[0038] 3. Flexible substrate:

[0039] The substrate is a 50μm thick polyimide film (PI-2545), which has excellent flexibility and high temperature resistance. The substrate surface is pretreated to ensure good adhesion, thus ensuring that the polyimide nanofiber layer is firmly fixed on its surface.

[0040] 4. Protective layer:

[0041] To improve the durability of the sensor, the protective layer uses a transparent polyurethane (PU) film with a thickness of 2μm, which can effectively prevent mechanical wear and chemical corrosion.

[0042] The protective layer not only protects the electrodes and nanofiber layer from the influence of the external environment, but also ensures the long-term stable operation of the sensor.

[0043] 5. Signal Processing Unit:

[0044] The sensor's signal is collected by electrodes and then transmitted to a signal processing unit. This unit includes a low-noise amplifier, a filtering circuit, and an analog-to-digital converter (ADC).

[0045] The signal processing unit amplifies the electrical signal, filters out noise, and finally converts the analog signal into a digital signal for output, facilitating subsequent processing and application.

[0046] Working principle:

[0047] When external pressure or vibration is applied to the piezoelectric sensor, the polyimide nanofiber layer deforms due to its piezoelectric properties, resulting in a charge distribution within the fiber layer. The electrode layer collects these charges, which are then processed by the signal processing unit to output an electrical signal proportional to the intensity of the external pressure or vibration.

[0048] Performance testing:

[0049] This sensor has good response sensitivity in the frequency range of 10Hz to 10kHz, and can detect slight pressure changes, making it suitable for physiological signal monitoring in smart wearable devices.

[0050] Tests showed that the sensor has a piezoelectric constant of 12 pC / N, and exhibits high output signal strength and low noise.

[0051] Example 2: High-frequency vibration sensor based on polyimide nanofibers

[0052] In this embodiment, the sensor is used to detect high-frequency vibration signals, and is particularly suitable for condition monitoring of industrial equipment.

[0053] 1. Polyimide nanofiber layer:

[0054] Polyimide nanofiber layers were prepared by electrospinning. Polyimide resin (PI-2555) was mixed with a solvent and then electrospun under the following conditions: voltage 20 kV, distance 18 cm, and solution concentration 12%.

[0055] By adjusting the electrospinning rate and solution concentration, polyimide nanofibers with a diameter of 100 nm were prepared.

[0056] The thickness of the polyimide nanofiber layer is 1 μm.

[0057] 2. Electrode layer:

[0058] The electrode is made of silver (Ag) material. A silver layer is deposited at both ends of the polyimide nanofiber layer by sputtering technology. The thickness of the silver electrode is 150 nm.

[0059] This structure ensures close contact between the electrode layer and the polyimide nanofiber layer, improving signal collection efficiency.

[0060] 3. Substrate:

[0061] The substrate is a transparent polyester film with a thickness of 40μm, which has good mechanical flexibility and light transmittance.

[0062] This substrate is suitable for detecting high-frequency vibration signals without interfering with optical monitoring.

[0063] 4. Protective layer:

[0064] The protective layer is made of polyurethane material with a thickness of 1μm, which can effectively prevent damage to the sensor from the external environment (such as chemical solvents, temperature changes, etc.).

[0065] 5. Signal Processing Unit:

[0066] The sensor employs a signal processing unit with anti-interference design, including a high-pass filter, amplifier, and precise analog-to-digital converter. This allows the sensor to accurately convert vibration signals into digital data.

[0067] Working principle:

[0068] This sensor responds to vibration or strain through a polyimide nanofiber layer. When the device or structure vibrates, the polyimide nanofiber layer undergoes minute deformation and generates an electrical signal through the piezoelectric effect. An electrode layer collects the electrical signal and outputs the final data through a signal processing unit.

[0069] Performance testing:

[0070] This sensor can effectively detect small-amplitude vibration changes in the frequency range of 1kHz to 10kHz, and has high response sensitivity.

[0071] The sensor has been tested and found to operate stably for over 5,000 hours, making it suitable for long-term monitoring of industrial equipment.

[0072] Example 3: Pressure Sensor Based on Polyimide Nanofibers

[0073] The sensor in this embodiment is designed for pressure detection, and is particularly suitable for scenarios in the medical and health field where dynamic monitoring of weight or pressure changes is required.

[0074] 1. Polyimide nanofiber layer:

[0075] Using a polyimide PI-2545 resin solution, the voltage was controlled at 18kV and the electrospinning distance at 20cm during the electrospinning process to obtain polyimide nanofibers with a diameter of approximately 300nm.

[0076] The polyimide nanofiber layer has a thickness of 1.5 μm.

[0077] 2. Electrode layer:

[0078] The electrode layer is made of copper (Cu) material with a thickness of 200 nm. It is deposited on both ends of the polyimide nanofiber layer by evaporation to ensure good conductivity.

[0079] 3. Substrate:

[0080] The substrate is a 50μm thick polyimide film, which has excellent flexibility and temperature resistance, making it suitable for medical sensor devices that require bending or deformation.

[0081] 4. Protective layer:

[0082] The protective layer is made of polyester material and is 1 μm thick, providing additional mechanical protection and enhancing the sensor's suitability for biomedical applications.

[0083] 5. Signal Processing Unit:

[0084] The signal processing unit includes a set of low-noise amplifiers, a high-precision analog-to-digital converter, and a highly adaptable digital signal output interface. These components enable the sensor to output pressure change data in real time.

[0085] Working principle:

[0086] When external pressure is applied to the sensor, the polyimide nanofiber layer deforms and converts it into an electrical signal through the piezoelectric effect. The electrode layer collects the electrical signal and transmits it to the signal processing unit, which ultimately outputs the pressure data.

[0087] Performance testing:

[0088] Tests showed that the sensor's pressure detection range is from 0.1 Pa to 1000 Pa, and its sensitivity and stability meet the requirements for medical monitoring.

[0089] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A piezoelectric sensor based on polyimide nanofibers, characterized in that, The sensor includes: The polyimide nanofiber layer has piezoelectric properties and can generate electrical signals in response to external mechanical stress, pressure or vibration changes. An electrode layer is disposed at both ends of the polyimide nanofiber layer, and the electrode layer is used to collect electrical signals generated by the polyimide nanofiber layer. A substrate, which supports the polyimide nanofiber layer and the electrode layer and provides mechanical support; A protective layer covers the electrode layer and the polyimide nanofiber layer, and the protective layer has the properties of resisting mechanical wear and chemical corrosion. The signal processing unit, connected to the electrode layer, is used to process the electrical signals generated by the polyimide nanofiber layer and output usable sensing signals.

2. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The polyimide nanofiber layer is a nanofiber layer prepared by electrospinning technology.

3. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The electrode layer is a conductive material selected from aluminum, copper, silver or gold, and the electrode layer is connected to the polyimide nanofiber layer by evaporation, sputtering or printing.

4. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The substrate is a flexible substrate, which is made of a flexible material selected from polyimide film, polyester film, polyester resin or glass fiber. The flexible substrate can be bent or stretched.

5. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The protective layer is a transparent polyurethane film or a polyimide film, and the thickness of the protective layer is from 0.1 μm to 10 μm.

6. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The signal processing unit includes an amplifier circuit, a filter circuit, and an analog-to-digital converter to enhance the stability and reliability of the signal and convert the analog signal generated by the sensor into a digital signal output.

7. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The sensor operates in the frequency range of 10Hz to 10kHz.

8. The piezoelectric sensor based on polyimide nanofibers according to claim 1, characterized in that, The piezoelectric constant of the sensor is greater than 10 pC / N.

Images