Lead zirconate titanate-based PVDF film induction preparation method, PVDF film and application

Abstract

The present invention discloses a method for inducing the preparation of a PVDF film based on lead zirconate titanate, a PVDF film, and applications thereof. The method comprises: step 1, preparing a PVDF solution; step 2, polarizing a PZT film; and step 3, forming a PVDF film. This method uses the polarized PZT to induce the growth of a PVDF film with a single orientation and a high β-orientation content. The resulting PVDF film exhibits a higher piezoelectric constant and electromechanical coupling coefficient, and is suitable for applications in a variety of fields, including piezoelectric crystal filters, triboelectric nanogenerators, sensors, brakes, and biological applications, with improved applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of PVDF films, and in particular relates to an induced preparation method of a PVDF film based on lead zirconate titanate, the PVDF film and applications. Background Art

[0002] Piezoelectric crystal filters are core components in the communications field. The quality of the channel is directly determined by the filter's filtering characteristics, and piezoelectric materials serve as the filter's core. In piezoelectric materials, the piezoelectric coefficient determines the filter's quality factor (Q), while the electromechanical coupling coefficient determines the filter's bandwidth. Therefore, studying how to improve the piezoelectric coefficient and electromechanical coupling coefficient of piezoelectric materials has become a key issue. Currently, the main piezoelectric materials used include inorganic piezoelectric crystal materials such as lithium niobate, lithium tantalate, zinc oxide, aluminum nitride, and lead zirconate titanate. However, the piezoelectric constant and electromechanical coupling coefficient of piezoelectric materials prepared from these materials are insufficient, and are gradually unable to meet the filter technology requirements for future wireless communications. Designing and developing new piezoelectric materials to significantly improve the piezoelectric constant and electromechanical coupling coefficient of piezoelectric materials is urgent and has good development prospects. Summary of the Invention

[0003] To obtain piezoelectric materials with higher piezoelectric constants and electromechanical coupling coefficients, the present invention provides a method for induced preparation of PVDF films based on lead zirconate titanate, PVDF films, and applications thereof. The polarized PZT induces the growth of PVDF films with a single orientation and a high β-orientation content.

[0004] According to a first aspect of the present invention, a method for inductively preparing a PVDF film based on lead zirconate titanate (PZT) is provided, comprising the following steps:

[0005] Step 1: Prepare PVDF solution: Add 1g of PVDF powder to 10-20ml of DMF solvent in a sealed container, mix and stir thoroughly until the PVDF is completely dissolved, and then place in a vacuum environment for full degassing;

[0006] Step 2: Polarize the PZT film: polarize the PZT film under a strong electric field for 10 minutes to 2 hours and clean it;

[0007] Step 3, PVDF film formation: The PVDF solution prepared in step 1 is formed into a film on the surface of the polarized PZT film in step 2, and then peeled off from the surface of the PZT film after drying to obtain a PVDF film.

[0008] Preferably, the PZT film has a bottom electrode, and the bottom electrode material is a conductive metal, preferably platinum.

[0009] Preferably, in step 3, the PVDF solution is directly coated on the surface of the PZT film to form a film; or the PZT film is immersed in the PVDF solution and allowed to stand for a period of time, so that the PVDF molecules form a film on the surface of the PZT film under the action of the surface charge of the PZT film. Directly coating the PVDF solution on the PZT surface is convenient and quick, and can improve film formation efficiency; using an immersion method can make the PVDF solution more uniform on the surface of the PZT film, resulting in better film quality.

[0010] Preferably, the direct coating method includes drop coating and spin coating, and the spin coating speed is 1500-2000 r / min and the time is 10-30 s.

[0011] Preferably, when the PZT film is immersed in the PVDF solution, the bottom electrode of the PZT film is grounded.

[0012] Preferably, the molecular weight of the PVDF powder in step 1 can be selected to be 100,000 to 1.8 million.

[0013] Preferably, the mixing and stirring speed in step 1 is 500-1000 r / min and the stirring time is 8-12 hours. The long stirring time allows the PVDF powder to be fully mixed with the solvent DMF, and the resulting solution concentration is uniform, so that the quality of each region of the film layer after subsequent film formation is highly consistent.

[0014] Preferably, the PZT thin film in step 2 has an area of ​​1×1 cm, and the PZT thin film is composed of single crystal or polycrystalline PZT, with a thickness of 100 nm to 100 um.

[0015] Preferably, the cleaning process is to rinse the polarized PZT film with an organic solvent and blow dry it, wherein the organic solvent includes but is not limited to acetone, and the drying process is performed using a nitrogen gun.

[0016] According to another aspect of the present invention, a PVDF film is also provided, which is prepared by the above method.

[0017] According to another aspect of the present invention, applications of the above-mentioned film in the fields of piezoelectric crystal filters, friction nanogenerators, sensors, brakes, and biological applications are also provided.

[0018] Compared with the existing technology, the present invention has the following advantages: simple operation, the obtained PVDF film has a single orientation and increased β crystal content, has a higher piezoelectric constant and electromechanical coupling coefficient, and can be used in piezoelectric crystal filters, friction nanogenerators, sensors, brakes and biological applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1Schematic diagram of the structure of the PZT film involved in the embodiment.

[0020] Figure 2 This is the Fourier transform infrared spectrum of the PVDF film in Example 3.

[0021] Figure 3 This is a scanning electron microscope image of the PVDF film in Example 3.

[0022] Figure 4 This is an atomic force microscope image of the PVDF film in Example 3. DETAILED DESCRIPTION

[0023] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0024] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0025] PZT thin film structure Figure 1 As shown, from bottom to top they are silicon substrate, conductive layer (i.e. bottom electrode) and PZT film.

[0026] Example 1:

[0027] 1) Weigh 1 g of PVDF powder and add it to a sealed container containing 20 mL of DMF solvent. Stir and dissolve it at room temperature for 12 hours, then place it in a vacuum diaphragm pump for 3 hours to degas.

[0028] 2) Cut a 1×1 cm PZT film and polarize it at 1 kV for 10 minutes. After polarization, rinse it with acetone and blow dry it with a nitrogen gun.

[0029] 3) Immerse the PZT film in PVDF solution for 8 hours, lead out the bottom electrode and ground it, then take it out, remove the excess solution on the surface, let it stand at room temperature until the solvent is completely evaporated, and then peel it off to obtain the PVDF film.

[0030] Example 2:

[0031] 1) Weigh 0.5 g of PVDF powder and add it to a sealed container containing 7.5 mL of DMF solvent. Stir and dissolve it at room temperature for 12 hours, then place it in a vacuum diaphragm pump for 3 hours to degas.

[0032] 2) Cut a 1×1 cm PZT film and polarize it at 1 kV for 10 minutes. After polarization, rinse it with acetone and blow dry it with a nitrogen gun.

[0033] 3) Drop 0.5 mL of PVDF solution on the PZT film and spin coat it at 500 r / min-10 s and 1500 r / min-20 s, then let it stand at room temperature until the solvent is completely evaporated. After peeling, the PVDF film is obtained.

[0034] Example 3:

[0035] 1) Weigh 0.5 g of PVDF powder and add it to a sealed container containing 7.5 mL of DMF solvent. Stir and dissolve it at room temperature for 12 hours, then place it in a vacuum diaphragm pump for 3 hours to degas.

[0036] 2) Cut a 1×1 cm PZT film and polarize it at 1 kV for 10 minutes. After polarization, rinse it with acetone and blow dry it with a nitrogen gun.

[0037] 3) Drop 0.5 mL of PVDF solution on the PZT film, let it stand at room temperature until the solvent is completely evaporated, and then peel it off to obtain the PVDF film.

[0038] Taking the PVDF film prepared in Example 3 as an example, its Fourier transform infrared spectrum is as follows: Figure 2 As shown in the figure, it can be seen that the prepared PVDF film has a high β crystal content and has good electrical properties.

[0039] The obtained PVDF film was scanned by scanning electron microscope to obtain the following Figure 3 The image shown illustrates that the PVDF film is well crystallized.

[0040] The prepared PVDF film was scanned by atomic force microscopy and the following Figure 4 The image shown shows that the surface of the PVDF film is relatively flat and dense, making it suitable for preparing piezoelectric crystal filters, friction nanogenerators, sensors and other devices.

[0041] In summary, the PVDF film prepared by the above method has a high β crystal content and a single orientation, and has a high piezoelectric constant and an electromechanical coupling system. It can be widely used in piezoelectric crystal filters, friction nanogenerators, sensors, brakes, and biological applications.

[0042] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for inducing the preparation of a PVDF film based on lead zirconate titanate PZT, characterized in that: The following steps are involved: Step 1, prepare PVDF solution: add 1g PVDF powder into a sealed container containing 10-20ml DMF solvent, mix and stir until PVDF is completely dissolved, and then place in a vacuum environment for full degassing. The molecular weight of the PVDF powder is 100,000 to 1.8 million; Step 2: Polarize the PZT film: polarize the PZT film under a strong electric field for 10 minutes to 2 hours and clean it; Step 3, PVDF film formation: forming a film on the surface of the polarized PZT film by the PVDF solution prepared in step 1 in step 2, and peeling it off from the surface of the PZT film after drying to obtain a PVDF film, wherein the film formation process includes: directly coating the PVDF solution on the surface of the PZT film to form a film; Alternatively, the PZT film is immersed in a PVDF solution and allowed to stand for a period of time, and the PVDF molecules form a film on the PZT surface under the action of the surface charge of the PZT film.

2. The method for inducing preparation of a PVDF film based on lead zirconate titanate (PZT) according to claim 1, characterized in that: The PZT film has a bottom electrode, and the bottom electrode material is a conductive metal.

3. The method for inducing preparation of a PVDF film based on lead zirconate titanate (PZT) according to claim 1 or 2, characterized in that: Direct coating methods include drop coating and spin coating, with a spin coating speed of 1500 to 2000 r / min and a time of 10 to 30 s.

4. The method for inducing preparation of a PVDF film based on lead zirconate titanate (PZT) according to claim 1 or 2, characterized in that: When the PZT film is immersed in the PVDF solution, the bottom electrode of the PZT film is grounded.

5. The method for inducing preparation of a PVDF film based on lead zirconate titanate (PZT) according to claim 1 or 2, characterized in that: In step 1, the mixing stirring speed is 500-1000 r / min, and the stirring time is 8-12 h.

6. The method for inducing preparation of a PVDF film based on lead zirconate titanate (PZT) according to claim 1 or 2, characterized in that: The PZT film described in step 2 has an area of ​​1×1 cm, and the PZT film is composed of single crystal or polycrystalline PZT, with a thickness of 100 nm to 100 um.

7. The method for inductively preparing a PVDF film based on lead zirconate titanate (PZT) according to claim 1 or 2, characterized in that: The cleaning process is to rinse the polarized PZT film with an organic solvent and blow it dry. The organic solvent includes but is not limited to acetone.

8. A PVDF film based on lead zirconate titanate PZT, characterized in that: The method according to any one of claims 1 to 7 is used for preparation.

9. An application of the PVDF film according to claim 8, characterized in that: The PVDF film is used for piezoelectric crystal filters, friction nanogenerators, sensors, brakes and biological applications.

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