Ferroelectric electret material based on 3D printing and preparation method and application thereof

Abstract

The invention discloses a ferroelectric electret material based on 3D printing and a preparation method and application thereof, and belongs to the technical field of functional materials and intelligent devices, the ferroelectric electret material comprises solid layers and porous layers, the solid layers are bonded to the two sides of the porous layers, and the porous layers are arranged in one of #-shaped grids or circular grids. By optimizing 3D printing parameters and autonomously regulating and controlling a ferroelectric electret material and a foam structure (pore size, pore shape, porosity and thickness), the ferroelectric electret material can stably store charges after polarization. According to the ferroelectric electret material based on 3D printing and the preparation method and application thereof, the printing precision is improved, the solid layer and the porous layer are prepared separately, the cell size is reduced, and the ferroelectric electret material with excellent piezoelectric performance for 3D printing is obtained; and moreover, accurate control of the foam structure of the ferroelectric electret material, material diversification and preparation process simplification are realized, and the ferroelectric electret material has remarkable advantages in performance and application potential.

Description

Technical Field

[0001] This invention relates to the field of functional materials and smart devices, and in particular to a ferroelectric electret material based on 3D printing, its preparation method, and its application. Background Technology

[0002] Ferroelectric electrets, as a new type of flexible piezoelectric material, possess a core advantage in efficiently combining the long-lasting charge storage capacity of electrets with the excellent electromechanical conversion properties of piezoelectric materials. Compared to traditional piezoelectric ceramics, their fabrication process is simpler and significantly less expensive, typically achieved through corona charging of polymer foam films, eliminating the need for high-temperature sintering and complex polarization processes. Their exceptional flexibility and plasticity allow them to perfectly conform to complex curved surfaces, providing ideal material support for electronic skin, flexible sensors, and health monitoring devices.

[0003] Currently, there are several technological foundations for the preparation of ferroelectric electrets. Chinese invention patent CN117309201A proposes a biodegradable and absorbable pressure sensor, using biodegradable materials (such as polylactic acid, chitosan, etc.) to prepare a porous electret film, and improving sensitivity and mechanical compressibility through a corrugated structure design. Its preparation process relies on traditional foaming and template methods, requiring the sacrifice of the template or prolonged soaking; it is difficult to achieve precise control of the micron-level pore structure, and the long-term stability of piezoelectric properties still needs further optimization. Chinese invention patent CN118870275A discloses a method: uniformly mixing polydimethylsiloxane (PDMS) prepolymer with a curing agent, adding anhydrous ethanol and stirring thoroughly to form a mixed material; this mixed material is then heated at high temperature, cured at low temperature, and then subjected to high-pressure polarization to finally obtain a ferroelectric electret. This method requires strict control of the raw material and curing agent ratio, stirring speed and time, and cannot precisely control the pore structure of the ferroelectric electret. The raw materials used in Chinese invention patent CN110148666A are roughly the same as those in CN118870275A, but additional sacrificial materials (such as sodium chloride crystals of a specific particle size) need to be introduced. Furthermore, the materials must be soaked in water for three days during the preparation process (with the water changed every 8 hours), resulting in a long preparation cycle and a complex process. Chinese invention patent CN103460423A uses materials such as polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene copolymer (FEP), forming structural components with the desired structure through extrusion or the introduction of gases such as nitrous oxide, and then polarizing them to obtain a ferroelectric electret. This method requires precise control of the angles at the spatial connections of the structural components, placing extremely high demands on the process control required for preparing high-quality ferroelectric electrets. Chinese invention patent CN102317066A first uses tools such as rollers and embossing molds to prepare polymer films with structured surfaces, then combines polymer films with different structures into composite materials through lamination, bonding, clamping, clamping, or threaded connections, and finally performs polarization treatment to obtain a ferroelectric electret. This method involves multiple tools to prepare diverse membrane structures and their subsequent composites, resulting in a lengthy and complex process.

[0004] In summary, existing ferroelectric electret fabrication techniques still have limitations, making it difficult to achieve a good balance between fabrication difficulty, efficiency, and the controllability of the resulting electret structure and properties. Therefore, there is an urgent need to develop a novel fabrication method that, while ensuring the acquisition of high-performance ferroelectric electrets, also features controllable pore structure, simple process, and higher efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a ferroelectric electret material based on 3D printing, its preparation method and application. By improving printing accuracy and preparing the solid layer and porous layer separately, the cell size is reduced, resulting in a 3D-printed ferroelectric electret material with excellent piezoelectric properties. Furthermore, it achieves precise structural control, material diversification and process simplification of the ferroelectric electret material, showing significant advantages in both performance and application potential.

[0006] To achieve the above objectives, the present invention provides a ferroelectric electret material based on 3D printing, comprising a solid layer and a porous layer, wherein the solid layer is bonded to both sides of the porous layer, and the porous layer is arranged in a grid pattern or a circular grid pattern.

[0007] Furthermore, the porous layers are arranged in other irregular porous shapes.

[0008] Preferably, the thickness of the porous layer d The range is: 0.02mm≤ d ≤0.05mm, the printing thickness of the porous layer is: one layer when the single layer thickness is 0.02mm, or two or more layers when the single layer thickness is 0.01mm, and the porosity of the porous layer is 5-50%.

[0009] Preferably, the solid layer and the porous layer are made of the same or different materials. The solid layer is made of PP, FEP, etc., and the porous layer is made of PP, PLA, TPU, etc.

[0010] This invention also provides a method for preparing a ferroelectric electret material based on 3D printing, comprising the following steps: S1. Write the 3D printer control program based on the porous layer material and the single-layer printing thickness; S2. Take a solid layer, with the adhesive side facing up, and fix it onto the printing plate. Place the printing plate into the marked position in the 3D printer and fix the printing plate in place. S3. Preheat the nozzle and heated bed according to the material to be printed in the porous layer; S4. Following the program written in S1, use a 3D printer to print. After printing, remove any residual material and complete the wire cutting process. S5. Take another solid layer and cover the porous layer printed in S4 with the adhesive side of the solid layer facing down, and cut the printed part into a film. S6. Polarize the printed and cut film to obtain the polarized ferroelectric electret material.

[0011] Preferably, in S3, the nozzle preheating temperature is 210-230℃, and the machine tool temperature after the bed is heated is 40-50℃.

[0012] Preferably, in S4, the 3D printer has an infill rate of 50-95% and an infill speed of 25-35 mm / s.

[0013] Furthermore, before operating the S5, remove the printing plate and allow it to cool naturally before performing the S5 operation.

[0014] Preferably, in S6, the polarization method is one of high-voltage corona polarization and contact polarization, the corona polarization voltage is ±10-20kV, the polarization time is 2-10min, the distance between the corona needle and the film is 1-10cm, and the contact polarization voltage is ±1-10kV.

[0015] Furthermore, 3D printing technology includes one of fused deposition modeling (FDM) and photopolymerization (PRC).

[0016] The present invention also provides an application of 3D-printed ferroelectric electret material, wherein the ferroelectric electret material prepared by the above-described 3D-printed ferroelectric electret material or the above-described method for preparing 3D-printed ferroelectric electret material is applied to piezoelectric sensors, loudspeakers or nanogenerators.

[0017] Preferably, the application procedure is as follows: first, determine the piezoelectric coefficient of the ferroelectric electret material. d 33 Afterwards, the electrodes are attached and applied to piezoelectric sensors, loudspeakers, or nanogenerators.

[0018] Therefore, the present invention, employing the above-mentioned 3D-printed ferroelectric electret material, its preparation method, and its application, has the following beneficial effects: (1) Compared with traditional methods, the new preparation method has greatly simplified the process, is easy to operate, highly adaptable, has a short preparation time, higher material utilization, and the cell structure can be designed independently. It also has excellent piezoelectric properties. The main features are: 1) The structure height is adjustable. By adjusting the parameters of the 3D model, the microstructure of the film (such as the shape, size and distribution of the pores) can be easily changed, thereby preparing ferroelectric electret films with different structural characteristics; 2) The operation process is simple and efficient. The entire preparation process mainly relies on the operation of the 3D printing equipment, supplemented by timely film surface post-treatment. The operation is simple and highly automated; 3) The printing material can be directly taken out as needed after being heated by the 3D printer. There is no need for complex chemical reactions, which significantly saves materials. At the same time, the 3D printing raw materials can be directly replaced to use different materials. (2) Since the material of the prepared ferroelectric electret, as well as the number of film layers, the size, shape and arrangement of pores can be controlled, the structure and material of the film can be continuously optimized based on previous experimental data, so as to prepare ferroelectric electret films with better performance. (3) When the ferroelectric electret composed of polypropylene (PP) solid layer-grid arrangement (TPU) porous layer-polypropylene (PP) solid layer is pressed, the voltage amplitude range is 0.3V-8.5V. It has high sensitivity under small force. After filtering and noise reduction, the sensitivity and stability can be further improved. It can be used for monitoring human vital signs signals, etc.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a 3D printing flowchart of a ferroelectric electret material based on 3D printing, its preparation method, and application examples 1 / 2 of the present invention; Figure 2 This is a schematic diagram of the longitudinal section of a ferroelectric electret material based on 3D printing, its preparation method, and application example 1 of the present invention; Figure 3 This is a surface optical image of a ferroelectric electret material based on 3D printing, its preparation method, and application example 1 of the present invention; Figure 4 This is an electrical signal curve for monitoring heartbeat and pulse in the following embodiment of the present invention: a ferroelectric electret material based on 3D printing, its preparation method, and application example 1. Figure 5 This is a voltage-time curve of the electrical signal monitoring the pressure of a ferroelectric electret material based on 3D printing, its preparation method and application example 2 of the present invention; Figure 6 This is a current-time curve of the electrical signal monitored by pressing, which is a 3D-printed ferroelectric electret material, its preparation method and application example 2 of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0024] Example 1 This invention provides a ferroelectric electret material based on 3D printing, comprising a solid layer and a porous layer. Solid layers are bonded to both sides of the porous layer, which is arranged in a grid pattern. The solid layer is made of PP material, using PP tape as the solid layer, and has a thickness of 50 μm. The porous layer is made of TPU material, with a side length of 2 cm and a thickness of 0.02 mm. The 3D printer has an infill rate of 80%, resulting in a measured porosity of approximately 20%. The porous layer consists of two layers, each 0.01 mm thick, and is printed in double layers.

[0025] The preparation method of ferroelectric electret materials based on 3D printing includes the following steps: S1. Write the 3D printer control program based on the porous layer material and the single-layer printing thickness; S2. Take a solid layer and fix it onto the printing plate with the adhesive side facing up. Place the printing plate into the marked position in the 3D printer and tighten the nuts on the machine to fix the printing plate in place to ensure that the position is correct and there is no warping. S3. Preheat the nozzle and heated bed. The nozzle temperature should be controlled at 230℃ and the machine tool temperature after the heated bed is 50℃. S4. Following the program written in S1, use a 3D printer to print. After printing, remove residual material and perform wire cutting. The infill rate is 80% and the infill speed is 30mm / s. S5. Wait and observe the printer complete printing the first porous layer. After the second intermediate layer is printed, the network is formed, and printing stops. The printing process is as follows: Figure 1 As shown. Remove the printing plate, take another solid layer, and cover the porous layer printed by S4 with the adhesive side of the solid layer facing down, and cut the printed part into a film; S6. The printed and cut film is polarized. Using a corona polarization device, the film is polarized in a strong electric field of 10kV / cm at room temperature for 5 minutes to obtain the corona-polarized ferroelectric electret material, denoted as TPU film. The corona polarization device adopts the structure of the existing technology.

[0026] Next, electrode tape was attached to both the positive and negative sides of the ferroelectric electret material. The positive electrode tape was connected to the positive terminal of the data acquisition instrument, and the negative electrode tape was connected to the negative terminal of the instrument and grounded. An insulating tape was wrapped around the test subject's wrist, and the TPU film with the electrodes attached was secured to the wrist at a point where the pulse was most prominent (usually below the thumb on the palm side). Then, the changes in the electrical signal generated by the TPU film were observed using a picoammeter.

[0027] The final cross-section of the TPU film is as follows Figure 2 Network structure, such as Figure 3The TPU film is a square with sides of 2cm. Experiments showed that the piezoelectric coefficient of this TPU film is 350~485pC / N, and it can detect the electrical signal changes of pulse at the wrist, as shown in the curve. Figure 4 As shown, by Figure 4 The test subject's heart rate was 96 bpm, proving that the prepared TPU film can effectively capture the tiny mechanical signals of the wrist pulse and convert them into stable electrical signals.

[0028] Example 2 The only difference between this embodiment and Embodiment 1 is that the porous layer material is PLA, and the final ferroelectric electret material is referred to as PLA thin film. All other conditions are the same.

[0029] The ferroelectric electret material was attached to the electrode and connected to the instrument (same as in Example 1). Insulating tape was pasted on both sides of the PLA film for insulation treatment. Then, it was pressed with a pressure of 20N and a frequency of 1Hz, and the changes in the electrical signal generated by the PLA film were observed.

[0030] Experiments showed that the piezoelectric coefficient of PLA film is similar to that of TPU film, with a Young's modulus of 2.7~3.5 GPa. The electrical signal change of the ferroelectric electret under 20 N pressure and 1 Hz frequency could be detected. Figure 5 and Figure 6 As shown, by Figure 5 and Figure 6 It can be seen that the maximum open-circuit voltage generated at 20N pressure and 1Hz frequency is 5V, and the maximum short-circuit current is 0.02μA, proving that the PLA film can accurately sense the charge change under pressure.

[0031] Therefore, this invention employs the aforementioned 3D-printed ferroelectric electret material, its preparation method, and its application. By improving printing accuracy and preparing the solid layer and porous layer separately, the cell size is reduced, resulting in a 3D-printed ferroelectric electret material with excellent piezoelectric properties. Furthermore, it achieves precise control over the ferroelectric electret cell structure, material diversification, and process simplification, demonstrating significant advantages in both performance and application potential.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A ferroelectric electret material based on 3D printing, characterized in that: It includes a solid layer and a porous layer, with the solid layer bonded to both sides of the porous layer. The porous layer is arranged in either a grid or a circular grid shape.

2. The ferroelectric electret material based on 3D printing according to claim 1, characterized in that: Thickness of porous layer d The range is: 0.02mm≤ d ≤0.05mm, the printing thickness of the porous layer is: one layer when the single layer thickness is 0.02mm, or two or more layers when the single layer thickness is 0.01mm, and the porosity of the porous layer is 5-50%.

3. The ferroelectric electret material based on 3D printing according to claim 1, characterized in that: The solid layer and the porous layer are made of the same or different materials. The solid layer is made of PP or FEP, and the porous layer is made of PP, PLA or TPU.

4. A method for preparing a ferroelectric electret material based on 3D printing as described in any one of claims 1-3, characterized in that: Includes the following steps: S1. Write the 3D printer control program based on the porous layer material and the single-layer printing thickness; S2. Take a solid layer, with the adhesive side facing up, and fix it onto the printing plate. Place the printing plate into the marked position in the 3D printer and fix the printing plate in place. S3. Preheat the nozzle and heated bed according to the material to be printed in the porous layer; S4. Following the program written in S1, use a 3D printer to print. After printing, remove any residual material and complete the wire cutting process. S5. Take another solid layer and cover the porous layer printed in S4 with the adhesive side of the solid layer facing down, and cut the printed part into a film. S6. Polarize the printed and cut film to obtain the polarized ferroelectric electret material.

5. The method for preparing a ferroelectric electret material based on 3D printing according to claim 4, characterized in that: In S3, the nozzle preheating temperature is 210-230℃, and the machine tool temperature after the bed is heated is 40-50℃.

6. The method for preparing a ferroelectric electret material based on 3D printing according to claim 4, characterized in that: In the S4, the infill rate of the 3D printer is 50-95%, and the infill speed is 25-35mm / s.

7. The method for preparing a ferroelectric electret material based on 3D printing according to claim 4, characterized in that: In S6, the polarization mode is one of high-voltage corona polarization and contact polarization. The corona polarization voltage is ±10-20kV, the polarization time is 2-10min, the distance between the corona needle and the membrane is 1-10cm, and the contact polarization voltage is ±1-10kV.

8. An application of a ferroelectric electret material based on 3D printing, characterized in that: The ferroelectric electret material prepared by the method of preparing the ferroelectric electret material based on 3D printing according to any one of claims 1-3 or any one of claims 4-7 can be applied to piezoelectric sensors, loudspeakers or nanogenerators.

9. The application of a ferroelectric electret material based on 3D printing according to claim 8, characterized in that: The application procedure is as follows: First, determine the piezoelectric coefficient of the ferroelectric electret material. d 33 Afterwards, the electrodes are attached and applied to piezoelectric sensors, loudspeakers, or nanogenerators.

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