Piezoelectric biomaterial composite film and method of manufacturing the same

Abstract

The present application relates to a piezoelectric biomaterial composite film, comprising piezoelectric biomaterial nanocrystals and a biodegradable biopolymer matrix, wherein the piezoelectric biomaterial nanocrystals have an average particle size of less than 2 μm and are wrapped by the biodegradable biopolymer matrix, and the piezoelectric biomaterial composite film has a Young's modulus of less than 400 MPa. The present application also relates to a method and device for manufacturing the piezoelectric biomaterial composite film, and a device comprising the piezoelectric biomaterial composite film. The piezoelectric biomaterial composite film of the present application has excellent biodegradability, flexibility and piezoelectric performance, and by selecting and adjusting the mass ratio of biomaterial nanocrystals and biopolymers, the biodegradation rate of the composite film can be controlled.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Provisional Application No. 63 / 763,895, filed with the United States Patent and Trademark Office on February 26, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to a biodegradable flexible piezoelectric biomaterial composite membrane and a method for manufacturing the same. More specifically, this application relates to a piezoelectric biomaterial composite membrane formed from a dense piezoelectric crystal and a biodegradable biopolymer matrix. Background Technology

[0004] The piezoelectric effect is the phenomenon where certain materials undergo electronic polarization or the reverse process when stress is applied. This effect enables the direct conversion between electrical and mechanical energy, leading to the widespread application of these materials in actuators, sensors, acoustic devices, nanoscale energy harvesters, and scanning probe microscopes. The piezoelectric effect can exist in ionic crystals, atomic crystals, and molecular crystals. Piezoelectric ionic crystals, represented by barium titanate (BTO) and lead zirconate titanate (PZT), have wide industrial and commercial applications due to their excellent electromechanical conversion, high Curie temperature, strong spontaneous polarization, and ability to be used in polycrystalline ceramic form. In contrast, piezoelectric molecular crystals typically exhibit weak piezoelectric properties caused by relatively weak intermolecular forces.

[0005] Transient implantable piezoelectric materials have attracted attention in biosensing, drug delivery, tissue regeneration, and antimicrobial and tumor therapies because non-degradable scaffolds and implants increase the risk of infection and inflammation. Piezoelectric materials for human applications should possess biocompatibility, biodegradability, and flexibility. However, conventional inorganic piezoelectric materials and piezoelectric polymers fail to meet the requirements related to biodegradability. Piezoelectric molecular biomaterials, due to their suitable solubility, biocompatibility, and biodegradability, represent a promising solution to these problems. However, the technological potential of these piezoelectric biomaterials is limited by several challenges, including their weak macroscopic piezoelectricity, poor mechanical properties, and inability to be mass-produced.

[0006] Despite the development of various self-assembly methods for synthesizing piezoelectric biomaterials, these methods remain challenging for cross-scale and large-scale fabrication due to time-consuming domain aligning processes and limited active control over biomolecules. Attempts to activate the piezoelectricity of large quantities of biomaterials through external polarization have proven largely unsuccessful due to the complex and hierarchical structure of biomaterials. In additive manufacturing methods based on nozzle inkjet printing, thin films can be selectively deposited layer by layer, offering advantages such as design geometric freedom, material utilization, and reduced fabrication time.

[0007] US Patent 2013 / 0052254A1 discloses a system and method for manufacturing a piezoelectric scaffold for tissue growth and repair. The piezoelectric scaffold system consists of a three-dimensional matrix of fibers formed from a biocompatible synthetic piezoelectric polymer material. Differentiable cells are seeded onto the fiber matrix to form a support scaffold for culturing these cells. Furthermore, the fiber matrix can stimulate the differentiated cells to differentiate into mature cells. Experiments have demonstrated that this polymer scaffold has the potential to promote tissue growth, differentiation, and / or repair.

[0008] US2023 / 0363283A1 discloses a method for fabricating piezoelectric bio-organic membranes with a piezoelectric ceramic crystal structure. During synthesis, an electric field is used not only to form nanocrystals but also to provide in-situ polarization, which promotes domain alignment throughout the membrane. The fabricated bio-organic membranes exhibit excellent piezoelectric properties and exceptionally good thermodynamic stability due to the nano-confinement effect. Furthermore, the proposed strategy overcomes the interface dependence of traditional self-assembly methods due to the uniform nucleation of the nanocrystals.

[0009] Nguyen et al. (2016) demonstrated the polarization alignment of peptides and peptide-based nanoenergy harvesters. The polarization is controlled by an electric field applied during peptide self-assembly. Uniform polarization is obtained in two opposite directions, where the effective piezoelectric constant dp 33 The efficiency reached 17.9 pm / V. The peptide-based energy harvester also exhibited an open-circuit voltage of 1.4 V and a power efficiency of 3.3 nW / cm². 2 The power density.

[0010] Yang et al. (2021) proposed a wafer-level fabrication method for piezoelectric biomaterial films based on γ-glycine crystals. The films have a sandwich structure in which crystalline glycine layers self-assemble and automatically align between two polyvinyl alcohol (PVA) films. The heterojunction glycine-PVA film exhibits a piezoelectric coefficient of 5.3 pm / V and shows an order of magnitude improvement in mechanical flexibility compared to pure glycine crystals. Although the γ-glycine-PVA film exhibits uniform piezoelectricity, the piezoelectric properties of glycine are not fully excited because the polarization orientation

[001] is inconsistent with the out-of-plane direction.

[0011] Zhang et al. (2024) discovered a synthetically produced biodegradable molecular crystal, HOCH2(CF2)3CH2OH [2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD)], with a piezoelectric strain coefficient d. 33 138 pm V -1 When HFPD is composited with polyvinyl alcohol to form a flexible piezoelectric film based on interface self-assembly, its d 33 Significantly reduced to 34.3 pm V-1 This is mainly due to uncontrollable grain orientation and displaced macroscopic domains.

[0012] Li et al. (2024) proposed a high-speed, one-step method for printing piezoelectric biofilms using thermo-electric driven aerosols. By adjusting the spatial organization and in-situ polarization of the biomolecular ink, the piezoelectric voltage coefficient of the membrane printed from β-glycine-polyvinylpyrrolidone was 190 × 10⁻⁶. -3 Vm N -1 This is higher than that of lead zirconate titanate, a commonly used piezoelectric material. However, nanoenergy harvesters based on β-glycine-polyvinylpyrrolidone (PVP) membranes exhibit uncontrollable degradation. The unidirectional polarization of the β-glycine-PVP membrane significantly weakens its optimal piezoelectricity and limits its output performance.

[0013] Therefore, one or more of the above-mentioned deficiencies or problems still need to be addressed or eliminated in the process of fabricating biodegradable flexible piezoelectric biomaterial membranes using roll-to-roll aerosol printing. Summary of the Invention

[0014] In one aspect, this application provides a piezoelectric biomaterial composite membrane, comprising: piezoelectric biomaterial nanocrystals; and a biodegradable biopolymer matrix, wherein the piezoelectric biomaterial nanocrystals have an average particle size of less than 2 μm and are coated by the biodegradable biopolymer matrix, and wherein the piezoelectric biomaterial composite membrane has an elastic modulus (e.g., Young's modulus) of less than 400 MPa.

[0015] In some embodiments, the piezoelectric biomaterial nanocrystals have an average particle size of less than 1.5 μm or 1 μm. In other embodiments, the piezoelectric biomaterial composite membrane has an elastic modulus (e.g., Young's modulus) of less than 350 MPa, less than 300 MPa, less than 250 MPa, or less than 200 MPa.

[0016] In some embodiments, the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystals is biodegradable. In other embodiments, the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystals is selected from amino acids, peptides, and proteins. In still other embodiments, the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystals is selected from glycine, L-alanine, DL-alanine, DL-threonine, DL-leucine, diphenylalanine, collagen, keratin, fast-acting proteins, and lysozyme.

[0017] In some embodiments, the biodegradable biopolymer matrix has a Young's modulus of less than 10 MPa, for example, less than 8 MPa or less than 5 MPa. In other embodiments, the biodegradable biopolymer matrix has a dielectric constant of less than 10, for example, less than 8 or less than 5. In still other embodiments, the biopolymer constituting the biodegradable biopolymer matrix is ​​selected from polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), polybutylene succinate (PBS), and polylactic-co-glycolic acid copolymer (PLGA).

[0018] In some embodiments, the piezoelectric biomaterial composite film has a dielectric constant of less than 10, for example, less than 8 or less than 5. In other embodiments, the piezoelectric biomaterial composite film has a thickness of less than 200 μm, for example, less than 150 μm or 100 μm. In still other embodiments, the mass ratio of the piezoelectric biomaterial nanocrystals to the biodegradable biopolymer matrix is ​​less than 3:1, for example, less than 2.5:1, less than 2:1, or less than 1:1.

[0019] In one aspect, this application provides a method for manufacturing the piezoelectric biomaterial composite film described herein, comprising: step 1) providing a composite ink comprising a piezoelectric biomaterial and a biopolymer dispersed in a solvent; step 2) forming composite nanodroplets from the composite ink under the action of an electric field and a thermal field, and causing nucleation and domain alignment to occur in the composite nanodroplets, thereby forming piezoelectric biomaterial nanocrystals in the composite nanodroplets; step 3) printing the composite nanodroplets from step 2) onto a substrate to form a liquid film; and step 4) drying the liquid film to obtain the piezoelectric biomaterial composite film.

[0020] In some embodiments, step 1) includes: providing a solution of piezoelectric biomaterial, providing a solution of biopolymer, and mixing the solution of piezoelectric biomaterial with the solution of biopolymer, preferably in a ratio (e.g., such that the mass ratio of piezoelectric biomaterial nanocrystals to the biodegradable biopolymer matrix is ​​less than 3:1, for example less than 2.5:1, less than 2:1, or less than 1:1), thereby obtaining the composite ink. In other embodiments, step 2) includes: ejecting the composite ink from a printing needle under the synergistic effect of an electric and thermal field to form composite nanodroplets, and achieving supersaturation of the composite nanodroplets by solvent evaporation in a thermo-electric field, thereby initiating homogeneous nucleation and domain alignment to form piezoelectric biomaterial nanocrystals in the composite nanodroplets. In still other embodiments, step 3) includes: printing the composite nanodroplets of step 2) onto a flexible substrate to form a continuous liquid film. In still other embodiments, step 4) includes: passing the liquid film of step 3) through heating and / or hot rollers to form a dry film, thereby obtaining the piezoelectric biomaterial composite film.

[0021] In some implementations, the method is aerosol roll-to-roll printing (AR2RP). In a preferred embodiment, the method includes a) providing a solution of piezoelectric biomaterial; b) providing a solution of biopolymer; c) mixing the solution of piezoelectric biomaterial and the solution of biopolymer in a certain ratio (e.g., such that the mass ratio of piezoelectric biomaterial nanocrystals to biodegradable biopolymer matrix is ​​less than 3:1, for example less than 2.5:1, less than 2:1, or less than 1:1) to obtain a well-dispersed composite ink containing biomaterial and biopolymer; d) forming an electric and thermal field between a printing needle and a printing platform, causing the composite ink to be discharged from the printing needle to form a stable microjet, which then splits into composite nanodroplets; e) supersaturating the composite nanodroplets by solvent evaporation in the thermo-electric field, resulting in homogeneous nucleation and domain alignment, thereby forming piezoelectric biomaterial nanocrystals; f) depositing the composite nanodroplets onto the printing platform to form a continuous liquid film on a flexible substrate; g) passing the liquid film on the flexible substrate through a heated printing platform and a heated roller to form a dry film, thereby obtaining the piezoelectric biomaterial composite film.

[0022] In one aspect, this application provides an apparatus for manufacturing the piezoelectric biomaterial composite membrane described herein, including a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

[0023] In some embodiments, the nanodroplet formation and nanocrystal assembly module includes: a heating device, a power supply, a printing needle, and two polarized electrodes, wherein the heating device is used to provide a thermal field between the flexible substrate and the printing needle, the printing needle is used to eject composite ink and is connected to the power supply to provide an electric field between the flexible substrate and the printing needle, and the two polarized electrodes are located between the printing needle and the flexible substrate to control the domain alignment direction of the nanocrystals and the arrival point of the nanocomposite droplets.

[0024] In a preferred embodiment, the nanodroplet formation and nanocrystal assembly module includes: a heating device, a power supply, a syringe, a conduit, a printing needle, a needle clip, and two polarized electrodes. The syringe contains a nanocomposite droplet and is connected to the printing needle via the conduit. One or more printing needles are disposed on the needle clip. The two polarized electrodes are set at 90° to each other and located at a distance of 5-20 mm from the flexible substrate.

[0025] In some embodiments, the roll-to-roll deposition module includes: a heated roller, a rewinder, a dewinder, a flexible substrate, a support roller, and a printing platform, wherein the printing platform is equipped with a heating device to regulate the temperature, the flexible substrate is unwound from the dewinder and stretched before passing through the support roller and the printing platform, the nanocomposite droplets are deposited on the flexible substrate to form a liquid film, the flexible substrate with the liquid film formed is passed through the heated printing platform and the heated roller to produce a dry film, the dry film being collected by the rewinder.

[0026] In some implementations, the control module includes a controller and a computer, wherein the controller receives control commands from the computer and outputs parameters to the roll-to-roll deposition module and the nanodroplet formation and nanocrystal assembly module, and the computer provides feedback on the printing process and adjusts the printing parameters in real time.

[0027] In one respect, this application provides an apparatus comprising the piezoelectric biomaterial composite membrane described above.

[0028] The biodegradable flexible piezoelectric biomaterial composite membrane and its related manufacturing method of this application have the following features and advantages: (1) The piezoelectric biomaterial composite membrane has excellent biodegradability, flexibility and piezoelectric properties. The biodegradation rate of the composite membrane can be controlled by selecting and adjusting the mass ratio of biomaterial nanocrystals and biopolymers.

[0029] (2) The manufacturing method of piezoelectric biomaterial composite film is free from the interface dependence of conventional self-assembly methods. The one-step high-speed thermo-electric driven 3D printing process can instantly adjust the spatial organization of biomolecular ink.

[0030] (3) The manufacturing method of piezoelectric biomaterial composite membrane is a new model of distributed production of customized piezoelectric biomaterial products, which has advantages in terms of design geometric freedom, material utilization rate and mass production. Attached Figure Description

[0031] The accompanying drawings contain illustrations of certain embodiments to further explain and clarify the above and other aspects, advantages, and features of this application, wherein the same reference numerals refer to the same or functionally similar elements. It should be understood that these drawings depict embodiments of this application and are not intended to limit the scope of protection sought. The content of this application is described and explained in more detail by using the following drawings.

[0032] Figure 1 This is a schematic diagram of an aerosol roll-to-roll printing (AR2RP) device based on the thermo-electric field effect, where 1: heating lamp; 2: precision jet pump; 3: syringe; 4: composite ink; 5: conduit; 6: needle clip; 7: stainless steel printing needle; 8: biomaterial composite nanodroplet; 9: power supply; 10: polarization electrode A; 11: polarization electrode B; 12: power supply A; 13: power supply B; 14: controller; 15: computer; 16: heated roller; 17: rewinder; 18: unwinder; 19: flexible substrate; 20: support roller; 21: printing platform; 22: heating rod.

[0033] Figure 2 This is a schematic diagram of a printing platform 21 having polarization electrode A 10 and polarization electrode B 11.

[0034] Figure 3 A flowchart illustrating a method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to an embodiment of this application is shown.

[0035] Figure 4 The structure of a biodegradable flexible piezoelectric biomaterial composite membrane according to an embodiment of this application is shown.

[0036] Figure 5 A schematically illustrates a needle clip for mounting nine printing needles according to an embodiment of this application.

[0037] Figure 5 Image B shows a needle clip with nine printing needles mounted according to an embodiment of this application.

[0038] Figure 6 An image showing a biodegradable flexible glycine / PCL membrane according to an embodiment of this application.

[0039] Figure 7Image A shows a scanning electron microscope (SEM) image of the surface morphology of the glycine / PCL film, with polarization conditions: polarization electrodes A 10 and B 11 are set at the same 90° rotation angle and their voltage is 0 V.

[0040] Figure 7 B shows a cross-sectional SEM image of the glycine / PCL membrane under the following polarization conditions: polarization electrodes A 10 and B 11 are set at the same 90° rotation angle and their voltage is 0 V, with a film thickness of approximately 5.7 μm.

[0041] Figure 8 SEM images showing the surface morphology of the glycine / PCL film are provided. Polarization conditions: polarization electrode A 10 and polarization electrode B 11 are set at the same 90° rotation angle, and the voltages of polarization electrode A 10 and polarization electrode B 11 are 2 kV and 0 kV, respectively.

[0042] Figure 9 The particle size distribution of a glycine / PCL membrane according to an embodiment of this application is shown.

[0043] Figure 10 The Young's modulus characterization of the piezoelectric composite material according to the embodiments of this application is shown.

[0044] Figure 11 The method of performing a knock test on a piezoelectric composite material according to an embodiment of this application is illustrated.

[0045] Figure 12 The correlation between the piezoelectric voltage output of the piezoelectric glycine / PCL composite membrane and the applied pressure is shown in the impact test. The membrane is manufactured according to an embodiment of this application and has a thickness of approximately 20 μm.

[0046] Figure 13 The piezoelectric voltage response of a glycine / PCL composite membrane with a thickness of approximately 20 μm, manufactured according to an embodiment of this application, is shown after 40 tapping cycles.

[0047] Figure 14 The piezoelectric voltage response of a glycine / PCL composite film with a thickness of approximately 20 μm manufactured according to an embodiment of this application after 22,000 tapping cycles is shown.

[0048] Figure 15 This demonstrates the biodegradability of a glycine / PVP composite membrane with a thickness of approximately 20 μm manufactured according to an embodiment of this application.

[0049] Those skilled in the art will understand that the elements in the accompanying drawings are shown for the purpose of brevity and clarity and are not necessarily described to scale. Detailed Implementation

[0050] It will be apparent to those skilled in the art that modifications (including additions and / or substitutions) can be made without departing from the scope and spirit of this application. Specific details may be omitted to avoid obscuring the disclosure of this application; however, the disclosure of this application is intended to enable those skilled in the art to practice the technical teachings herein without undue experimentation.

[0051] The piezoelectric biomaterial composite membrane of this application is formed from dense nanocrystals and a biodegradable biopolymer matrix. Furthermore, the manufacturing method of this invention, known as aerosol roll-to-roll printing (AR2RP), provides a high-throughput 3D printing process for the instantaneous formation of biomolecular membranes, wherein an in-situ thermo-electric field promotes biomolecular assembly, and various parameters of the spatial organization of the composite material are dynamically adjusted in real time (on the fly). The AR2RP device includes a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

[0052] The biodegradable flexible piezoelectric biomaterial composite membrane of this application comprises: 1) piezoelectric biomaterial nanocrystals having an average particle size of less than 2 μm and being coated with a biodegradable biopolymer; 2) a biopolymer matrix having a dielectric constant of less than 10, a Young's modulus of less than 10 MPa and biodegradability.

[0053] The inventors of this application have discovered that only when the particle size of piezoelectric biomaterial crystals is less than 2 μm can they be appropriately regulated under the influence of an external electric field to achieve optimal phase orientation, thereby obtaining the maximum piezoelectric performance. Therefore, piezoelectric biomaterial crystals should have an average particle size of less than 2 μm, preferably less than 2 μm. When the average particle size of the crystals is greater than 2 μm, the proportion of random orientations increases significantly.

[0054] The inventors of this application would also like to emphasize that although the term "piezoelectric biomaterial nanocrystals" is used, the crystals only need to have an average particle size of less than 2 μm; that is, they are not necessarily limited to an average particle size in the nanometer range. Therefore, in this document, "piezoelectric biomaterial nanocrystals" and "piezoelectric biomaterial crystals" can be used interchangeably.

[0055] In some embodiments, the mass ratio of piezoelectric biomaterial nanocrystals to biopolymers is less than 3:1. For example, the mass ratio can be 3:1, 2.5:1, 2:1, 1:1, or lower. In some embodiments, the Young's modulus of the biodegradable flexible piezoelectric biomaterial composite membrane is less than 400 MPa. In some embodiments, the thickness of the biodegradable flexible piezoelectric biomaterial composite membrane is less than 200 μm.

[0056] In some embodiments, the piezoelectric biomaterial constituting the nanocrystals is biodegradable and includes amino acids such as glycine, L-alanine, DL-alanine, DL-threonine, and DL-leucine, peptides such as diphenylalanine, and proteins such as collagen, keratin, prestin, and lysozyme. In a preferred embodiment, the biomaterial constituting the nanocrystals is glycine.

[0057] In some embodiments, the biodegradable biopolymers include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polycaprolactone (PCL), and other biodegradable polymers. In preferred embodiments, the biopolymers are PCL and PVP. In some embodiments, the biodegradation rate of the piezoelectric biomaterial composite membrane can be controlled by selecting and adjusting the mass ratio of biomaterial nanocrystals to biopolymers.

[0058] Accordingly, this application provides a method and corresponding manufacturing apparatus for producing biodegradable flexible piezoelectric biomaterial composite membranes.

[0059] The aerosol roll-to-roll printing (AR2RP) equipment consists of three parts: a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

[0060] The nanodroplet formation and nanocrystal assembly module includes: a heating lamp 1, a precision jet pump 2, a syringe 3, composite ink 4, a conduit 5, a needle clip 6, a stainless steel printing needle 7, a biomaterial composite nanodroplet 8, a power supply 9, polarization electrode A 10, polarization electrode B 11, power supply A 12, and power supply B 13. The heating lamp 1 is placed between the substrate and the printing needle to provide a thermal field. The syringe 3, containing composite ink 4, is placed above the precision jet pump 2 and connected to the stainless steel printing needle 7 via the conduit 5. The printing needle 7 is mounted on the needle clip 6. The needle clip 6 is movable along the Z-axis to adjust the printing height. The needle clip 6 is insulated. Multiple stainless steel printing needles 7 can be mounted on the needle clip 6 to increase deposition throughput. The high-voltage power supply 9 is connected to the conductive stainless steel printing needle 7 to provide an electric field between the substrate and the printing needle. The biomaterial composite nanodroplet 8 is formed in the electric-thermal field. Polarization electrodes A 10 and B 11 are set at 90° to each other and located 5-20 mm from the substrate. The purpose of these polarization electrodes is to alter the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals and the arrival point of the nanodroplets to form the designed structure. The voltages of polarization electrodes A10 and B11 are generated by power supplies A12 and B13, respectively. Polarization electrodes A10 and B11 can be rotated 180°.

[0061] The roll-to-roll deposition module includes a heated roller 16, a rewinder 17, an unwinder 18, a flexible substrate 19, a support roller 20, and a printing platform 21. A heating rod 22 is embedded in the printing platform 21 to regulate its temperature. The flexible substrate 19 unfolds from the unwinder 18 and is mechanically braked to provide tension before passing through the support roller 20 and the printing platform 21. Biomaterial composite nanodroplets 8 are deposited on the flexible substrate 19. After deposition, the liquid film on the flexible substrate 19 passes through the heated printing platform 21 and the heated roller 16 to produce a dry film. The dry film is finally collected on the roller of the rewinder 17.

[0062] The control module includes a controller 14 and a computer 15. The controller 14 receives control commands from the computer via a USB data cable and outputs parameters to the roll-to-roll deposition module and the nanodroplet formation and nanocrystal assembly module. The computer 15 uses monitoring software to provide feedback on the printing process and adjusts printing parameters in real time, including temperature, voltage, and substrate movement speed.

[0063] A method for manufacturing biodegradable flexible piezoelectric biomaterial composite membranes using an aerosol roll-to-roll printing (AR2RP) device includes the following steps: 1) Provide a solution for piezoelectric biomaterials; 2) Provide a solution of biopolymer; 3) Mix the piezoelectric biomaterial solution and the biopolymer solution in a certain proportion to obtain a well-dispersed composite ink containing biomaterial and biopolymer 4; 4) The composite ink 4 is pushed into the stainless steel printing needle 7 at a constant speed using the precision jet pump 2. The precision jet pump 2 is used to adjust the flow rate of the composite ink 4 during the printing process. The high voltage power supply 9 applies high voltage between the printing needle 7 and the printing platform 21 to form an electric field. The heating lamp 1 applies high temperature between the stainless steel printing needle 7 and the printing platform 21 to form a thermal field. Due to the synergistic effect of the electric field and the thermal field, the composite ink 4 is dragged from the printing needle 7 to form a stable micro-liquid jet, and then splits into biomaterial composite nanodroplets 8.

[0064] 5) Real-time dynamic activation of supersaturation of biomaterial composite nanodroplets is achieved through solvent evaporation in a thermo-electric field. Controller 14 regulates the temperature of the thermal field. Biomaterial composite nanodroplets 8 are deposited in the thermal field. As the surface area to volume ratio of the atomized droplets increases, the concentration and supersaturation of the nanodroplets increase, and homogeneous nucleation and domain alignment occur, forming nanocrystals. During the nanodroplet deposition process, polarization electrodes A 10 and B 11 are set to optimized rotation angles, and optimized voltages are set to change the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals, and the arrival point of the nanodroplets is controlled to form the designed film structure.

[0065] 6) Biomaterial composite nanodroplets 8 with nanocrystals are deposited onto the printing platform 21 to form a continuous liquid film on the flexible substrate 19.

[0066] 7) After deposition, the liquid film on the flexible substrate 19 passes through the heated printing platform 21 and the heated roller 16 to form a dry film. Finally, the dry film is collected on the roller of the rewinder 17.

[0067] In some embodiments, the biomaterials constituting the nanocrystals include: amino acids, such as glycine, L-alanine, DL-alanine, DL-threonine, and DL-leucine; peptides, such as diphenylalanine; and proteins, such as collagen, keratin, fast protein, and lysozyme. In a preferred embodiment, the biomaterial constituting the nanocrystals is glycine.

[0068] In some embodiments, the solution of the piezoelectric biomaterial is provided by dissolving the biomaterial powder in a solution, for example, dissolving glycine in water or diphenylalanine in 1,1,1,3,3,3-hexafluoro-2-propanol. In a preferred embodiment, the solution of the piezoelectric biomaterial is provided by dissolving 10 g of glycine in 100 ml of water.

[0069] In some embodiments, the biopolymer includes polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polycaprolactone (PCL), and other biodegradable polymers. In preferred embodiments, the biopolymers are PCL and PVP.

[0070] In some embodiments, the biopolymer solution is provided by dissolving the biopolymer powder in a solution, such as dissolving PVP in water or PCL in 2,2,2-trifluoroethanol. In a preferred embodiment, the biopolymer solution is provided by dissolving 15 g of PVP in 100 ml of water or 1 g of PCL in 100 ml of 2,2,2-trifluoroethanol.

[0071] In some embodiments, the solutions of piezoelectric biomaterials and biopolymers are mixed at a mass ratio of less than 3:1. For example, the mass ratio can be 3:1, 2.5:1, 2:1, 1:1, or lower.

[0072] In some implementations, the outer diameter and inner diameter of the stainless steel printing needle 7 are 0.7 mm and 0.4 mm, respectively.

[0073] In some implementations, the flow rate of composite ink 4 is 10 μl / min. -1 Up to 200 μl min -1 For example, 30, 50, 80, 100, 120, 150, 180 μl min-1 , and the range formed by any two of them.

[0074] In some implementations, the voltage output of power supply 9 is set to 2 kV to 25 kV, such as 5, 8, 10, 12, 15, 18, 20 and 23 kV, and any two of them.

[0075] In some implementations, the temperature of the thermal field is set to 30°C to 70°C, for example 35, 40, 45, 50, 55, 60 or 65°C, and any two of them.

[0076] In some implementations, the printing height of the printing needle 7 is set from 2 mm to 50 mm, such as 5, 10, 15, 20, 25, 30, 35, 40 or 45 mm, and any two of them.

[0077] In some implementations, the dimensions (height, width, and thickness) of polarization electrode A 10 and polarization electrode B 11 are 30 × 3.0 × 0.5 mm.

[0078] In some implementations, the voltage outputs of power supplies A 12 and B 13 are set to -20 kV to 20 kV, such as -15, -10, -5, 5, 10, 15 kV, and any two of them.

[0079] In some embodiments, the moving speed of the flexible substrate 19 is set to 0.5 mm / s to 50 mm / s, for example 1, 5, 10, 15, 20, 25, 30, 35, 40 or 45 mm / s, and any two of them.

[0080] In some implementations, the thickness of the deposited film is adjusted by changing the flow rate of the composite ink 4, the moving speed of the flexible substrate 19, and the number and position of the stainless steel printing needles 7 mounted in the needle holder 6.

[0081] In some implementations, the domain alignment orientation and intensity of the nanocrystals in the deposited film are adjusted by changing the rotation angle of polarizing electrode A 10 and polarizing electrode B 11 and by applying voltage.

[0082] In some embodiments, the flexible substrate 19 includes a flexible material with a conductive coating, such as a copper foil, steel foil, or a polymer film-coated conductive nanomaterial.

[0083] In some embodiments, the conductive nanomaterials include Au, Ag, Mg, Mo, and Cu, or any combination thereof.

[0084] In some implementations, the dry piezoelectric biomaterial composite membrane is obtained in an unsupported form by peeling it off from the flexible substrate 19.

[0085] The method of this application may further include: clamping at least two biodegradable electrodes on each surface of the piezoelectric biomaterial composite membrane according to the embodiment, and then stacking a protective biodegradable layer on each of the at least two electrodes to form an assembly, thereby obtaining the flexible biodegradable piezoelectric biomaterial composite material of this application.

[0086] In some embodiments, a molybdenum (Mo) film is coated on each surface of the biodegradable flexible piezoelectric biomaterial composite membrane, which serves as an electrode. Preferably, the Mo film is coated on the surface of the flexible piezoelectric biomaterial composite membrane by sputtering.

[0087] In some embodiments, a PLA film is further coated onto the Mo film. Preferably, the PLA is coated onto the Mo film by spin coating.

[0088] Exemplary Implementation

[0089] 1. A biodegradable flexible piezoelectric biomaterial composite membrane, including: 1) Piezoelectric biomaterial nanocrystals with an average particle size of less than 2 μm and coated with biopolymer; 2) The biopolymer matrix has a dielectric constant of less than 10 and a Young's modulus of less than 10 MPa, and is biodegradable.

[0090] 2. The biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the mass ratio of piezoelectric biomaterial nanocrystals to biopolymers is less than 3:1.

[0091] 3. A biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the composite membrane has a Young's modulus of less than 400 MPa and a dielectric constant of less than 10. In this paper, the Young's modulus was measured according to ISO 527-3 standard, and the dielectric constant was measured using a standard impedance analyzer.

[0092] 4. The biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the piezoelectric biomaterial constituting the nanocrystal is biodegradable and includes amino acids such as glycine, L-alanine, DL-alanine, DL-threonine, and DL-leucine, peptides such as diphenylalanine, and proteins such as collagen, keratin, fast protein, and lysozyme.

[0093] 5. A biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the biopolymers include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polycaprolactone (PCL), and other biodegradable polymers.

[0094] 6. The biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the biodegradation rate of the piezoelectric biomaterial composite membrane can be controlled by selecting and adjusting the mass ratio of biomaterial nanocrystals and biopolymers.

[0095] 7. A thermo-electric field-based aerosol roll-to-roll printing (AR2RP) apparatus for manufacturing a biodegradable flexible piezoelectric biomaterial composite film according to the foregoing embodiments, wherein the apparatus includes a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

[0096] 8. An aerosol roll-to-roll printing (AR2RP) device according to the aforementioned embodiment, wherein the nanodroplet formation and nanocrystal assembly module includes: a heating lamp, a precision jet pump, a syringe, composite ink, a conduit, a needle clip, a stainless steel printing needle, biomaterial composite nanodroplets, a power supply, polarization electrode A, polarization electrode B, power supply A, and power supply B. A heating lamp is placed between the substrate and the printing needle to provide a thermal field; a syringe filled with composite ink is placed above a precision ink pump and connected to a stainless steel printing needle via a conduit; the printing needle is mounted on a needle clip; the needle clip can move along the Z-axis to adjust the printing height; the needle clip is insulated; multiple stainless steel printing needles can be mounted on the needle clip to increase deposition throughput; a high-voltage power supply is connected to the conductive stainless steel printing needle to provide an electric field between the substrate and the printing needle; biomaterial composite nanodroplets are formed in the electric-thermal field; polarized electrodes A and B are set at 90° to each other and located 5-20 mm from the substrate; the purpose of the polarized electrodes is to change the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals and control the arrival point of the nanodroplets to form the designed structure; the voltages of polarized electrodes A and B are generated by power supplies A and B, respectively; polarized electrodes A and B can be rotated 180°.

[0097] 9. An aerosol roll-to-roll printing (AR2RP) apparatus according to the foregoing embodiments, wherein the roll-to-roll deposition module includes: a hot roller, a rewinder, an unwinder, a flexible substrate, a support roller, and a printing platform; Heating rods are embedded in the printing platform to regulate its temperature; the flexible substrate is unwound from the unwinder and mechanically braked to provide tension before passing through the support rollers and printing platform; biomaterial composite nanodroplets are deposited on the flexible substrate; after deposition, the liquid film on the flexible substrate passes through the heated printing platform and hot rollers to produce a dry film; the dry film is finally collected on the rollers of the rewinder.

[0098] 10. An aerosol roll-to-roll printing (AR2RP) apparatus according to the foregoing embodiments, wherein the control module includes: a controller and a computer; The controller receives control commands from the computer via a USB data cable and outputs parameters to the roll-to-roll deposition module and the nanodroplet formation and nanocrystal assembly module. The computer uses monitoring software to provide feedback on the printing process and adjusts printing parameters in real time, including temperature, voltage, and substrate movement speed.

[0099] 11. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane using an aerosol roll-to-roll printing (AR2RP) apparatus based on an embodiment, comprising: 1) Provide a solution for piezoelectric biomaterials; 2) Provide a solution of biopolymer; 3) Mix the piezoelectric biomaterial solution and the biopolymer solution in a certain proportion to obtain a well-dispersed composite ink containing biomaterial and biopolymer; 4) A precision jet pump pushes the composite ink into the stainless steel printing needle at a constant speed. The precision jet pump is used to adjust the flow rate of the composite ink during the printing process. A high voltage power supply applies high voltage between the printing needle and the printing platform to form an electric field. A heating lamp applies high temperature between the stainless steel printing needle and the printing platform to form a thermal field. Due to the synergistic effect of the electric field and the thermal field, the composite ink is dragged from the printing needle to form a stable micro-liquid jet, and then splits into biomaterial composite nanodroplets. 5) Real-time dynamic activation of supersaturation of biomaterial composite nanodroplets is achieved through solvent evaporation in a thermo-electric field; the controller adjusts the temperature of the thermal field; biomaterial composite nanodroplets are deposited in the thermal field; as the surface area to volume ratio of the atomized droplets increases, the concentration and supersaturation of the nanodroplets increase, and homogeneous nucleation and domain alignment occur to form nanocrystals; during the nanodroplet deposition process, polarization electrodes A and B are set to optimized rotation angles, and optimized voltages are set to change the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals, and the arrival point of the nanodroplets is controlled to form the designed film structure; 6) Biomaterial composite nanodroplets with nanocrystals are deposited onto a printing platform to form a continuous liquid film on a flexible substrate; 7) After deposition, the liquid film on the flexible substrate is passed through a heated printing platform and hot rollers to form a dry film, which is finally collected on the rollers of the rewinder.

[0100] 12. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the biomaterial constituting the nanocrystals includes: amino acids such as glycine, L-alanine, DL-alanine, DL-threonine, DL-leucine, peptides such as diphenylalanine, and proteins such as collagen, keratin, fast protein, and lysozyme.

[0101] 13. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the solution of the piezoelectric biomaterial is provided by dissolving biomaterial powder in a solution, for example, dissolving glycine in water or diphenylalanine in 1,1,1,3,3,3-hexafluoro-2-propanol.

[0102] 14. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the biopolymer includes polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polycaprolactone (PCL) and other biodegradable polymers.

[0103] 15. A method for manufacturing a biodegradable and flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein a solution of the biopolymer is provided by dissolving biopolymer powder in a solution, for example, dissolving PVP in water or PCL in ethyl acetate.

[0104] 16. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the mass ratio of the piezoelectric biomaterial solution to the biopolymer solution is less than 3:1.

[0105] 17. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the outer diameter and inner diameter of the stainless steel printing needle are 0.7 mm and 0.4 mm, respectively.

[0106] 18. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiment, wherein the flow rate of the composite ink is 10 μl / min. -1 Up to 200 μl min -1 .

[0107] 19. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the voltage output of the power supply is set to 2 kV to 25 kV.

[0108] 20. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the temperature of the thermal field is set to 30°C to 70°C.

[0109] 21. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the printing height of the printing needle is set to 2 mm to 50 mm.

[0110] 22. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the moving speed of the flexible substrate is set to 0.5 mm / s to 50 mm / s.

[0111] 23. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the aforementioned embodiment, wherein the thickness of the deposited membrane can be adjusted by changing the flow rate of the composite ink, the moving speed of the flexible substrate, and the number and position of the stainless steel printing needles mounted in the needle holder.

[0112] 24. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the flexible substrate comprises a flexible material having a conductive coating, such as a copper foil, steel foil, or a conductive nanomaterial coated with a polymer film.

[0113] 25. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite film according to the foregoing embodiments, wherein the conductive nanomaterials include Au, Ag, Mg, Mo and Cu, or any combination thereof.

[0114] 26. A method for manufacturing a biodegradable flexible piezoelectric biomaterial composite membrane according to the foregoing embodiments, wherein the piezoelectric biomaterial composite membrane is obtained in an unsupported form by peeling it from a flexible substrate.

[0115] 27. A piezoelectric device, including the biodegradable flexible piezoelectric biomaterial composite membrane of the aforementioned embodiments.

[0116] Example

[0117] The following specific examples are provided to further explain and illustrate the concept of this application; however, these specific examples are not intended to identify essential or critical features, nor are they intended to limit the scope of protection claimed in this application. Those skilled in the art can employ equivalent technical means to implement the various technical solutions disclosed in this application.

[0118] refer to Figure 1 The aerosol roll-to-roll printing (AR2RP) device based on the thermo-electric field effect mainly consists of three parts: a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

[0119] The nanodroplet formation and nanocrystal assembly module includes: a heating lamp 1, a precision jet pump 2, a syringe 3, composite ink 4, a conduit 5, a needle clip 6, a stainless steel printing needle 7, a biomaterial composite nanodroplet 8, a power supply 9, polarization electrode A 10, polarization electrode B 11, power supply A 12, and power supply B 13. The heating lamp 1 is placed between the substrate and the printing needle to provide a thermal field. The syringe 3, containing composite ink 4, is placed above the precision jet pump 2 and connected to the stainless steel printing needle 7 via the conduit 5. The printing needle 7 is mounted on the needle clip 6. The needle clip 6 is movable along the Z-axis to adjust the printing height. The needle clip 6 is insulated. Multiple stainless steel printing needles 7 can be mounted on the needle clip 6 to increase deposition throughput. The high-voltage power supply 9 is connected to the conductive stainless steel printing needle 7 to provide an electric field between the substrate and the printing needle. The biomaterial composite nanodroplet 8 is formed in the electric-thermal field. Polarization electrode A 10 and polarization electrode B 11 are set at 90° to each other (see [link to documentation]). Figure 2 The polarizing electrodes are located 5-20 mm from the substrate. Their purpose is to alter the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals and the arrival point of the nanodroplets to form the designed structure. The voltages of polarizing electrodes A 10 and B 11 are generated by power supplies A 12 and B 13, respectively. Polarizing electrodes A 10 and B 11 can be rotated 180°.

[0120] The roll-to-roll deposition module includes a heated roller 16, a rewinder 17, an unwinder 18, a flexible substrate 19, a support roller 20, and a printing platform 21. A heating rod 22 is embedded in the printing platform 21 to regulate its temperature. The flexible substrate 19 unfolds from the unwinder 18 and is mechanically braked to provide tension before passing through the support roller 20 and the printing platform 21. Biomaterial composite nanodroplets 8 are deposited on the flexible substrate 19. After deposition, the liquid film on the flexible substrate 19 passes through the heated printing platform 21 and the heated roller 16 to produce a dry film. The dry film is finally collected on the roller of the rewinder 17.

[0121] The control module includes a controller 14 and a computer 15. The controller 14 receives control commands from the computer via a USB data cable and outputs parameters to the roll-to-roll deposition module and the nanodroplet formation and nanocrystal assembly module. The computer 15 uses monitoring software to provide feedback on the printing process and adjusts printing parameters in real time, including temperature, voltage, and substrate movement speed.

[0122] refer to Figure 3 The paper provides a flowchart of the fabrication of biodegradable flexible piezoelectric biomaterial composite membranes using the AR2RP method, including the preparation of homogeneous glycine / PCL composite ink, the formation of nanodroplets, the induction of nucleation and domain alignment to form glycine nanocrystals, and the deposition of glycine nanocrystals and PCL onto a flexible substrate.

[0123] Figure 4 The structure of a biodegradable flexible piezoelectric biomaterial composite membrane with four main components is shown, including PCL filler as a framework and soft elastic filler, glycine nanocrystals as a piezoelectric framework, PCL coating, and Mo coating.

[0124] The preparation method includes: 1) Dissolving 10% w / v glycine powder in deionized water and 5% w / v PCL powder in ethyl acetate, and then stirring and mixing the glycine solution and PCL solution under a magnetic rotator until a uniform composite ink 4 is obtained.

[0125] 2) Place syringe 3 above precision jet pump 2. Syringe 3 is filled with composite ink 4. Syringe 3 is connected to stainless steel printing needles 7 via tubing 5. Nine printing needles are mounted on needle clip 6, distributed as follows: Figure 5 As shown in A) and B) of 5. The inner diameter of the printing needle hole is 0.4 mm. The needle clip 6 is fixed on the Z-axis, and the printing height is set to 8 mm. The needle clip 6 is insulated. The output terminal of the high-voltage power supply 9 is connected to the conductive printing needle 7. The output voltage of the high-voltage power supply 9 is 6000 V. The heating lamp 1 is placed between the substrate and the printing needle to provide a thermal field, and the temperature is set to 60°C. Due to the synergistic effect of the electric field and the thermal field, the ink is dragged from the stainless steel printing needle 7 to form a stable micro-liquid jet, which then splits into biomaterial composite nanodroplets 8 containing nanoscale ink droplets.

[0126] 3) Biomaterial composite nanodroplets 8 are deposited in a thermal field. As the surface area to volume ratio of the atomized droplets increases, the concentration and supersaturation of the nanodroplets increase, and homogeneous nucleation and domain alignment occur, forming nanocrystals. During the nanodroplet deposition process, two polarization conditions are set to change the electric field near the nanodroplets to control the domain alignment direction of the nanocrystals and control the arrival point of the nanodroplets to form the designed film structure: 1. Polarization electrodes A 10 and B 11 are set to a 90° rotation angle, and their voltage is 0 V; 2. Polarization electrodes A 10 and B 11 are set to a 90° rotation angle, and their voltages are 0 V and 2000 V, respectively.

[0127] 4) Biomaterial composite nanodroplets 8 containing glycine nanocrystals are deposited on the printing platform 21 to form a continuous liquid film on the flexible substrate 19. After deposition, the liquid film on the flexible substrate 19 is passed through the heated printing platform 21 and the heated roller 16 to form a dry film. Finally, the dry film is collected on the roller of the rewinder 17. The temperature of the heated printing platform 21 and the heated roller 16 is set to 40°C.

[0128] Figure 6 An image of a biodegradable flexible glycine / PCL membrane with a thickness of 100 μm, a width of 0.2 m, and a length of 2 m is shown.

[0129] Figure 7 A shows a scanning electron microscope (SEM) image of the surface morphology of the glycine / PCL film: Polarization conditions: polarization electrodes A 10 and B 11 are set at the same 90° rotation angle and their voltage is 0 V.

[0130] Figure 7 B shows a cross-sectional SEM image of the glycine / PCL membrane under the following polarization conditions: polarization electrodes A 10 and B 11 are set at the same 90° rotation angle and their voltage is 0 V.

[0131] Figure 8 SEM images showing the surface morphology of the glycine / PCL film are provided. Polarization conditions: polarization electrode A 10 and polarization electrode B 11 are set at the same 90° rotation angle, and the voltages of polarization electrode A 10 and polarization electrode B 11 are 2 kV and 0 kV, respectively.

[0132] Figure 9 The particle size distribution of the glycine / PCL membranes is shown, with an average particle size of 0.45 μm.

[0133] Figure 10 The Young's modulus characterization of the glycine / PCL membrane is shown. The Young's modulus of the glycine / PCL piezoelectric composite membrane (glycine solution and PCL solution, mass ratio 1:2) is approximately 83 MPa (tested according to ISO 527-3 standard), significantly lower than the Young's modulus of glycine crystals (approximately 30 GPa for α-glycine, approximately 28 GPa for γ-glycine, and approximately 15 GPa for β-glycine). Materials with this modulus can cover a range of tissues (tendons, skin, muscle, etc.). The relatively low Young's modulus allows for the application of glycine / PCL membranes in tissue engineering.

[0134] To obtain the piezoelectric response of the glycine / PCL membrane under different deformation modes, a piezoelectric output experiment was designed. Figure 11 A schematic diagram of a knock test performed by a vibration generator is shown, featuring a controlled oscillation frequency and knocking force. The knocking force is adjusted by the distance between the knocking post and the sample surface, which can be detected and quantified using a mechanical force sensor. The piezoelectric output voltage is measured using a digital oscilloscope (Rohde & Schwarz RTE1024). The tested film is a 20 μm thick glycine / PCL coated with a sputtered Mo electrode (100 nm thick).

[0135] Figures 12 to 14 The piezoelectric response of a 20 μm thick glycine / PCL film is shown. In the tapping mode ( Figure 11In this device, when compressive force is applied during a 40 Hz tapping process, a high open-circuit voltage output is generated. Under an applied tapping pressure of 2.1 MPa, the output voltage reaches approximately 9 V. Figure 12 The correlation between the piezoelectric voltage output of the piezoelectric glycine / PCL composite membrane and the applied pressure is shown in the knock test. Figure 13 The piezoelectric voltage response of the glycine / PCL composite film after 40 tapping cycles is shown. The flexible glycine / PCL piezoelectric composite film also exhibits good durability under long-term deformation. Figure 14 The piezoelectric voltage response of the glycine / PCL composite membrane after 22,000 tap cycles is shown. The output voltage remains constant during the 22,000 tap cycles.

[0136] Since both glycine and the selected biopolymers are biodegradable, the deposited glycine / biopolymer membrane is also biodegradable in the natural environment. Figure 15 The biodegradability of a glycine / PVP composite membrane with a thickness of approximately 20 μm is shown. The glycine / PVP membrane underwent an expansion process and then ruptured on a soil surface after 0.25 hours. Finally, it was completely biodegraded after 2 hours. The biodegradation rate of the piezoelectric biomaterial composite membrane can be controlled by selecting and adjusting the mass ratio of biomaterial nanocrystals and biopolymers.

[0137] Industrial application potential

[0138] Due to its excellent biodegradability, flexibility, biocompatibility, piezoelectric properties, and environmental sustainability, the composite membrane of this application can be used as a high-performance implantable biosensor, bioactuator, bioenergy harvester, etc.

[0139] The method for manufacturing piezoelectric biomaterial composite membranes based on thermo-electric driven aerosol roll-to-roll printing in this application can be used for large-scale industrial production, enabling the production of micron-sized piezoelectric smart devices, and can be used for truly distributed production.

[0140] 3D printing, which involves the layer-by-layer deposition of nanocrystals ejected from pinholes, offers unparalleled material versatility, freedom in product geometry design, and short manufacturing times.

[0141] The technical features of any of the above embodiments can be combined with the technical features of another embodiment without departing from the inventive concept of this application, and the resulting new technical solution still falls within the scope of this application.

[0142] These embodiments / examples are described to better explain the principles and applications of this application, enabling those skilled in the art to understand the various embodiments and modifications of this application, but do not constitute any limitation on this application. The scope of this application should be defined by the claims and their equivalents.

Claims

1. Piezoelectric biomaterial composite membrane, including: Piezoelectric biomaterial nanocrystals; and Biodegradable biopolymer matrix The piezoelectric biomaterial nanocrystals described herein have an average particle size of less than 2 μm and are coated with the biodegradable biopolymer matrix. The piezoelectric biomaterial composite membrane has a Young's modulus of less than 400 MPa.

2. The piezoelectric biomaterial composite membrane according to claim 1, wherein the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystals is biodegradable; Preferably, the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystal is selected from amino acids, peptides, and proteins; Preferably, the piezoelectric biomaterial constituting the piezoelectric biomaterial nanocrystal is selected from glycine, L-alanine, DL-alanine, DL-threonine, DL-leucine, diphenylalanine, collagen, keratin, fast protein, and lysozyme.

3. The piezoelectric biomaterial composite membrane according to claim 1, wherein the biodegradable biopolymer matrix has a Young's modulus of less than 10 MPa; Preferably, the biodegradable biopolymer matrix has a dielectric constant of less than 10; Preferably, the biopolymer constituting the biodegradable biopolymer matrix is ​​selected from polyvinyl alcohol, polyvinylpyrrolidone, polylactic acid, polycaprolactone, polyhydroxyalkanoates, polybutylene succinate, and polylactic-co-hydroxyacetic acid copolymer.

4. The piezoelectric biomaterial composite membrane according to any one of claims 1 to 3, wherein the piezoelectric biomaterial composite membrane has a dielectric constant of less than 10; Preferably, the piezoelectric biomaterial composite membrane has a thickness of less than 200 μm; Preferably, the mass ratio of the piezoelectric biomaterial nanocrystals to the biodegradable biopolymer matrix is ​​less than 3:1, for example less than 2.5:1, less than 2:1, or less than 1:

1.

5. A method for manufacturing a piezoelectric biomaterial composite membrane according to any one of claims 1 to 4, comprising: Step 1) Provide a composite ink comprising piezoelectric biomaterials and biopolymers dispersed in a solvent; Step 2) Under the action of electric and thermal fields, the composite ink is formed into composite nanodroplets, and nucleation and domain alignment occur in the composite nanodroplets, thereby forming piezoelectric biomaterial nanocrystals in the composite nanodroplets; Step 3) Print the composite nanodroplets from step 2) onto the substrate to form a liquid film; and Step 4) Dry the liquid film to obtain the piezoelectric biomaterial composite film.

6. The method according to claim 5, wherein: Step 1) includes: providing a solution of piezoelectric biomaterial, providing a solution of biopolymer, and mixing the solution of piezoelectric biomaterial with the solution of biopolymer, preferably in a proportional manner, to obtain the composite ink; or Step 2) includes: under the synergistic effect of an electric field and a thermal field, ejecting the composite ink from the printing needle to form composite nanodroplets; and achieving supersaturation of the composite nanodroplets through solvent evaporation in the thermal-electric field, thereby initiating homogeneous nucleation and domain alignment, and forming piezoelectric biomaterial nanocrystals in the composite nanodroplets; or Step 3) includes: printing the composite nanodroplets from step 2) onto a flexible substrate to form a continuous liquid film; or Step 4) includes: passing the liquid film from step 3) through heating and / or hot rollers to form a dry film, thereby obtaining the piezoelectric biomaterial composite film.

7. The method according to claim 5 or 6, wherein: The method is a roll-to-roll printing of aerosol adhesive, preferably comprising: a) Provide a solution for piezoelectric biomaterials; b) Provide a solution of the biopolymer; c) The solution of the piezoelectric biomaterial and the solution of the biopolymer are mixed in a certain proportion to obtain a well-dispersed composite ink containing biomaterial and biopolymer; d) An electric and thermal field is formed between the printing needle and the printing platform, causing the composite ink to be discharged from the printing needle to form a stable micro-liquid jet, which then splits into composite nanodroplets; e) The composite nanodroplets are supersaturated by solvent evaporation in a thermo-electric field, resulting in homogeneous nucleation and domain alignment, thereby forming piezoelectric biomaterial nanocrystals; f) The composite nanodroplets are deposited onto a printing platform to form a continuous liquid film on a flexible substrate; g) Passing the liquid film on the flexible substrate through a heated printing platform and hot rollers to form a dry film, thereby obtaining the piezoelectric biomaterial composite film.

8. An apparatus for manufacturing a piezoelectric biomaterial composite membrane according to any one of claims 1 to 4, comprising a nanodroplet formation and nanocrystal assembly module, a roll-to-roll deposition module, and a control module.

9. The apparatus according to claim 8, wherein: The nanodroplet formation and nanocrystal assembly module includes: a heating device, a power supply, a printing needle, and two polarized electrodes. The heating device is used to provide a thermal field between the flexible substrate and the printing needle. The printing needle is used to eject composite ink and is connected to the power supply to provide an electric field between the flexible substrate and the printing needle. The two polarized electrodes are located between the printing needle and the flexible substrate to control the domain alignment direction of the nanocrystals and the arrival point of the nanocomposite droplets. The roll-to-roll deposition module includes: a heated roller, a rewinder, a dewinder, a flexible substrate, a support roller, and a printing platform. The printing platform is equipped with a heating device to regulate the temperature. The flexible substrate is unwound from the dewinder and stretched before passing through the support roller and the printing platform. The nanocomposite droplets are deposited on the flexible substrate to form a liquid film. The flexible substrate with the liquid film is passed through the heated printing platform and the heated roller to produce a dry film. The dry film is collected by the rewinder. The control module includes a controller and a computer, wherein the controller receives control commands from the computer and outputs parameters to the roll-to-roll deposition module and the nanodroplet formation and nanocrystal assembly module, and the computer provides feedback on the printing process and adjusts the printing parameters in real time. Preferably, the nanodroplet formation and nanocrystal assembly module includes: a heating device, a power supply, a syringe, a conduit, a printing needle, a needle clip, and two polarized electrodes, wherein the syringe contains nanocomposite ink and is connected to the printing needle through the conduit, the needle clip is provided with one or more printing needles, and the two polarized electrodes are set at 90° to each other and located at a distance of 5-20 mm from the flexible substrate.

10. An apparatus comprising the piezoelectric biomaterial composite membrane according to any one of claims 1 to 4.

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