Ferroelectric polymer-based nanocomposites for driving, their preparation methods and applications

Abstract

This invention belongs to the technical field of flexible actuation materials. It discloses a ferroelectric polymer-based nanocomposite material for actuation, its preparation method, and its application. The method includes the following steps: (1) dissolving a ferroelectric polymer with polar and nonpolar molecular conformations in an organic solvent to obtain a polymer solution; (2) dispersing nanofillers in the polymer solution to obtain a mixed solution, placing the mixed solution in a metal container and allowing it to stand at room temperature to allow the solvent to evaporate naturally and form a film, and then removing it to obtain the ferroelectric polymer-based nanocomposite material. This invention utilizes the interface effect between the ferroelectric polymer and nanoparticles to reduce the driving electric field of molecular structure phase transition, thereby obtaining excellent actuation performance. Furthermore, through a simple preparation method, it can simultaneously improve strain and elastic energy density, thus solving the problem that current ferroelectric polymer materials used as electric actuators have large driving electric fields and low output driving elastic energy.

Description

Technical Field

[0001] This invention belongs to the technical field of flexible drive materials, and more specifically, relates to a ferroelectric polymer-based nanocomposite material for drive, its preparation method and application. Background Technology

[0002] In recent years, with the rapid development of the smart hardware market, flexible electronics technology has become one of the research hotspots. Flexible actuation materials enable electronic devices to be thinner and lighter, and to adapt to more complex shapes and strain environments. Among them, ferroelectric polymers have been widely studied in the field of flexible actuation materials due to their advantages such as fast response speed, large actuation strain, high biocompatibility, and ease of processing.

[0003] The high electrostriction generated by ferroelectric polymers originates from the phase transition between the polar and nonpolar isomers of their molecular structure when an electric field is applied. Under normal conditions, the transition between these two molecular conformations depends on a large driving electric field (>100 MV / m). Furthermore, due to the low Young's modulus of polymers, their driven elastic energy density is typically more than an order of magnitude lower than that of common electro-driven materials (such as piezoelectric ceramics or single crystals), making it difficult to meet the requirements of certain applications with high driving forces. Therefore, achieving large strain and high elastic energy density in ferroelectric polymer-based material systems under low electric fields is one of the core technical challenges in designing novel flexible actuation materials. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a ferroelectric polymer-based nanocomposite material for driving, its preparation method, and its application. It utilizes the interfacial effect between the ferroelectric polymer and nanoparticles to reduce the driving electric field of molecular structure phase transition, thereby achieving excellent driving performance. Furthermore, through a simple preparation method, it can simultaneously improve strain and elastic energy density, thus solving the problem that current ferroelectric polymer materials used as electric actuators have large driving electric fields and low output driving elastic energy.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a ferroelectric polymer-based nanocomposite material for driving is provided, characterized in that the method includes the following steps:

[0006] (1) Dissolve ferroelectric polymers with polar and nonpolar molecular conformations in an organic solvent to obtain a polymer solution;

[0007] (2) The nanofiller is dispersed in a polymer solution to obtain a mixed solution. The mixed solution is placed in a metal container and left to stand at room temperature. After the solvent evaporates naturally to form a film, it is taken out to obtain a ferroelectric polymer-based nanocomposite material.

[0008] Furthermore, the ferroelectric polymer is polyvinylidene fluoride or a polyvinylidene fluoride copolymer having polar and nonpolar molecular conformations.

[0009] Furthermore, the organic solvent is any one of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0010] Furthermore, the concentration of the polymer solution is 10 mg / mL to 100 mg / mL, the stirring time is 6 hours to 12 hours, and the temperature is 25℃ to 40℃.

[0011] Furthermore, the nanofiller is dispersed in the polymer solution by ultrasonication for 5 to 60 minutes at a power of 75 W to 300 W.

[0012] Furthermore, the nanofiller is TiO2 nanoparticles or ZnO nanoparticles.

[0013] Furthermore, the particle size of the nanoparticles is 10 nm to 100 nm, and the volume ratio of nanoparticles to ferroelectric polymer is 10% to 22.5%.

[0014] Furthermore, the ferroelectric polymer is polyvinylidene fluoride, the organic solvent is DMF, the nanofiller is TiO2 nanoparticles, and the volume of the TiO2 nanoparticles is 14.9% of the volume of PVDF.

[0015] The present invention also provides a ferroelectric polymer-based nanocomposite material for driving, which is prepared by the preparation method of ferroelectric polymer-based nanocomposite material as described above.

[0016] The present invention also provides an application of the ferroelectric polymer-based nanocomposite material as described above in flexible actuators.

[0017] In summary, compared with the prior art, the ferroelectric polymer-based nanocomposite materials for driving, their preparation methods, and applications provided by this invention have the following beneficial effects:

[0018] 1. This invention utilizes the interfacial effect between ferroelectric polymers and nanoparticles to reduce the driving electric field of molecular structure phase transition, thereby achieving excellent driving performance and solving the problem that current ferroelectric polymer materials used as electric actuators have large driving electric fields and low output driving elastic energy.

[0019] 2. The preparation method described herein only utilizes ultrasonic vibration to disperse nanoparticles in a ferroelectric polymer solution, without requiring modification of the ferroelectric polymer and nanoparticles. It is simple to operate and is green and economical.

[0020] 3. This invention significantly improves the strain and elastic energy density of the composite material by introducing a high content of nanoparticles into the ferroelectric polymer. Under an electric field strength of 40 MV / m, the PVDF / TiO2 composite material containing 14.9 vol% TiO2 exhibits an electrostricted strain of 8% and an elastic energy density of 11.3 J / cm². 3 It is superior to commercially available single-crystal ceramics and ferroelectric polymers.

[0021] 4. The ferroelectric polymer-based nanocomposite material prepared by this invention has the characteristics of large strain and high elastic energy density under low electric field, and can be used to make flexible actuators, which can meet the application requirements of various large stroke and long displacement actuators and micro-machines, such as soft robots, artificial muscles, tissue engineering and wearable biomedical devices. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of a method for preparing a ferroelectric polymer-based nanocomposite material for driving, provided by this invention.

[0023] Figure 2 (a) and (b) in Example 1 of this invention are schematic diagrams showing the strain magnitude of the ferroelectric polymer-based nanocomposite material under different electric fields and its strain performance compared with that of PVDF and TiO2.

[0024] Figure 3 This is a schematic diagram of the stability test of the ferroelectric polymer-based nanocomposite material obtained in Example 1 of this invention;

[0025] Figure 4 This is a schematic diagram showing the relationship between the deformation of the ferroelectric polymer-based nanocomposite material obtained in Example 1 of the present invention and the frequency.

[0026] Figure 5 (a) and (b) in the figures are Fourier transform infrared spectra and molecular change diagrams of the ferroelectric polymer-based nanocomposites obtained in Examples 1, 2 and 3 of the present invention, respectively. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] This invention provides a method for preparing ferroelectric polymer-based nanocomposite materials for driving applications, the method mainly comprising the following steps:

[0029] Step 1: Dissolve the ferroelectric polymer with polar and nonpolar molecular conformations in an organic solvent to obtain a polymer solution.

[0030] The ferroelectric polymer is polyvinylidene fluoride (PVDF) or a polyvinylidene fluoride copolymer with polar and nonpolar molecular conformations, such as polyvinylidene fluoride-hexafluoropropylene (P(VDF-HFP)).

[0031] The organic solvent can be any one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP). The concentration of the polymer solution is 10 mg / mL to 100 mg / mL, the stirring time is 6 hours to 12 hours, and the temperature is 25℃ to 40℃.

[0032] Step 2: Disperse the nanofiller in the polymer solution to obtain a mixed solution. Place the mixed solution in a metal container and let it stand at room temperature to allow the solvent to evaporate naturally and form a film. Then take it out to obtain the ferroelectric polymer-based nanocomposite material.

[0033] Specifically, the nanofiller is dispersed in the polymer solution by ultrasonication for 5 min to 60 min at a power of 75 W to 300 W; the nanofiller is TiO2 nanoparticles or ZnO nanoparticles; the particle size of the nanoparticles is 10 nm to 100 nm, and the volume ratio of the nanoparticles to the ferroelectric polymer is 10% to 22.5%.

[0034] The metal container is made of aluminum, gold, silver, copper, or aluminum alloys. The film is formed by the slow evaporation of the solvent at room temperature, between 20°C and 25°C.

[0035] The present invention also provides a ferroelectric polymer-based nanocomposite material for driving, which is prepared by the preparation method of the ferroelectric polymer-based nanocomposite material for driving as described above.

[0036] The present invention also provides an application of the ferroelectric polymer-based nanocomposite material for driving as described above in flexible driving devices.

[0037] The present invention will be further described in detail below with reference to several specific embodiments.

[0038] Example 1

[0039] Please see Figure 2 , Figure 3 and Figure 4In Example 1, 0.5 g of PVDF was added to 10 mL of DMF solution to prepare a polymer solution with a concentration of 50 mg / mL. The solution was stirred at 300 rpm / min for 8 hours at 25 °C. TiO2 nanoparticles with a particle size of 21 nm were then added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 14.9% of the volume of the PVDF. The performance comparison results of the composite material prepared in Example 1 with typical drive materials are detailed in Table 1.

[0040] Table 1. Performance Comparison of Example 1 and Typical Electro-Actuating Materials

[0041]

[0042]

[0043] Example 2

[0044] Please see Figure 5 In Example 2, 0.5 g of P(VDF-HFP) was added to 10 mL of DMF solution to prepare a polymer solution with a concentration of 50 mg / mL. The solution was stirred at 300 rpm / min for 8 hours at 25°C. TiO2 nanoparticles with a particle size of 21 nm were then added to the solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25°C to form a film. The volume of the TiO2 nanoparticles was 14.9% of the volume of P(VDF-HFP).

[0045] Example 3

[0046] In Example 3, 0.5 g of PVDF was added to 10 mL of DMF solution to prepare a polymer solution with a concentration of 50 mg / mL. The solution was stirred at 300 rpm / min for 8 hours at 25°C. ZnO nanoparticles with a particle size of 18 nm were then added to the solution, and the mixture was ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25°C to form a film. The volume of the ZnO nanoparticles was 14.9% of the volume of the PVDF.

[0047] Example 4

[0048] In Example 4, 0.5 g of P(VDF-HFP) was added to 10 mL of DMF solution to prepare a polymer solution with a concentration of 50 mg / mL. The solution was stirred at 300 rpm / min for 8 hours at 25°C. ZnO nanoparticles with a particle size of 18 nm were then added to the solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25°C to form a film. The volume of the ZnO nanoparticles was 14.9% of the volume of P(VDF-HFP).

[0049] Comparison Case 1

[0050] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of PVDF to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C. TiO2 nanoparticles with a particle size of 21 nm were then added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 9.3% of the volume of the PVDF.

[0051] Comparison Case 2

[0052] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of PVDF to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C. TiO2 nanoparticles with a particle size of 21 nm were then added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 4.2% of the volume of the PVDF.

[0053] Comparison Case 3

[0054] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of PVDF to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C. TiO2 nanoparticles with a particle size of 21 nm were then added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 2.1% of the volume of the PVDF.

[0055] Comparison Case 4

[0056] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of PVDF to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C. ZnO nanoparticles with a particle size of 18 nm were then added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the ZnO nanoparticles was 4.3% of the volume of the PVDF.

[0057] Comparison Case 5

[0058] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of P(VDF-HFP) to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C to ensure complete dissolution of the polymer. TiO2 nanoparticles with a particle size of 21 nm were added to the PVDF solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 9.3% of the volume of P(VDF-HFP).

[0059] Comparison Case 6

[0060] A polymer solution with a concentration of 50 mg / mL was prepared by adding 0.5 g of polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) to 10 mL of DMF solution. The solution was stirred at 300 rpm / min for 8 hours at 25 °C to ensure complete dissolution of the polymer. TiO2 nanoparticles with a particle size of 21 nm were added to the solution and ultrasonically dispersed for 5 min at a power of 175 W. The solution was then poured directly into an aluminum tray and allowed to evaporate naturally at 25 °C to form a film. The volume of the TiO2 nanoparticles was 14.9% of the volume of P(VDF-TrFE). The electrostrain performance comparison results between Example 1 and Comparative Cases 1-6 are detailed in Table 2.

[0061] Table 2. Comparison of electrostrain performance between Example 1 and Comparative Examples 1-6

[0062]

[0063] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a ferroelectric polymer-based nanocomposite material for driving applications, characterized in that, The method includes the following steps: (1) Dissolve ferroelectric polymers with polar and nonpolar molecular conformations in an organic solvent to obtain a polymer solution; (2) The nanofiller is dispersed in a polymer solution to obtain a mixed solution. The mixed solution is placed in a metal container and left to stand at room temperature. After the solvent evaporates naturally to form a film, it is taken out to obtain a ferroelectric polymer-based nanocomposite material. The ferroelectric polymer is polyvinylidene fluoride, the organic solvent is DMF, and the nanofiller is TiO2 nanoparticles, with the volume of TiO2 nanoparticles being 14.9% of the volume of PVDF.

2. The method for preparing the ferroelectric polymer-based nanocomposite material for driving as described in claim 1, characterized in that: The concentration of the polymer solution was 10 mg / mL to 100 mg / mL, the stirring time was 6 hours to 12 hours, and the temperature was 25°C to 40°C.

3. The method for preparing the ferroelectric polymer-based nanocomposite material for driving as described in claim 1, characterized in that: The nanofiller was dispersed in the polymer solution by ultrasonication for 5 min to 60 min at a power of 75 W to 300 W.

4. The method for preparing the ferroelectric polymer-based nanocomposite material for driving as described in claim 1, characterized in that: The nanoparticles have a particle size of 10 nm to 100 nm, and the volume ratio of nanoparticles to ferroelectric polymers is 10% to 22.5%.

5. A ferroelectric polymer-based nanocomposite material for driving applications, characterized in that: The ferroelectric polymer-based nanocomposite material is prepared by the preparation method of the ferroelectric polymer-based nanocomposite material according to any one of claims 1-4.

6. The application of the ferroelectric polymer-based nanocomposite material for drive as described in claim 5 in a flexible drive device.

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