Microstructure biocrystal piezoelectric flexible electronic device and preparation method and application thereof
By fabricating microstructured biocrystal piezoelectric flexible electronic devices, the limitations of existing flexible electronic devices in terms of material biocompatibility and structural design have been overcome. Stability and visual monitoring of piezoelectric signals have been achieved, making them suitable for real-time sensing of human motion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-13
- Publication Date
- 2026-04-14
AI Technical Summary
Existing flexible electronic devices have limitations in terms of material biocompatibility and structural design, resulting in weak signal transmission, low sensitivity, and most devices only have a single electrical signal sensing function, making it difficult to achieve fast, intuitive and accurate feedback.
A method for fabricating microstructured biocrystal piezoelectric flexible electronic devices was adopted. By forming a microstructured biocrystal layer on a template using a mixed solution of polyvinyl alcohol, glycine, PEDOT:PSS and gelatin, and combining it with a polyurethane film and a silica positive structure template, a sandwich structure with a conductive network was prepared, which enhances piezoelectric sensitivity and signal strength.
It achieves dual sensing performance with piezoelectric response and visual monitoring, enabling real-time monitoring of human movement, improving the strength and stability of signal output, and possessing excellent biocompatibility and biodegradability.
Smart Images
Figure CN121865841A_ABST
Abstract
Description
Technical fields: This invention belongs to the field of biomedical materials technology, specifically relating to a microstructured biocrystal piezoelectric flexible electronic device, its preparation method, and its application. Background technology: Flexible electronics, as an ideal alternative to traditional electronic products, have attracted much attention due to their excellent flexibility, multifunctionality, and high integration, and are widely studied in fields such as wearable technology, personalized medical monitoring, and artificial electronic skin. For many years, flexible electronic devices based on conductive mechanisms have been extensively explored, capable of converting external stimuli into detectable electrical signals. In recent years, with the rapid development of flexible energy harvesting technology, self-powered flexible electronic devices that do not require an external power source have gained increasing attention, exhibiting significant characteristics and broad application potential. Despite considerable progress, significant challenges remain in constructing integrated wearable electronic devices that are miniaturized and biocompatible with the skin. Furthermore, common self-powered flexible electronic devices often suffer from inadequate structural design, resulting in weak signal transmission and low sensitivity, severely limiting their practical application value. Simultaneously, most devices only possess a single electrical signal sensing function, which poses a significant challenge to achieving fast, intuitive, and accurate feedback. Therefore, developing novel self-powered flexible electronic products with skin-adaptive components, optimized structural design, and diversified sensing methods remains a research direction worthy of focused attention and anticipation.
[0003] Based on this, the present invention proposes a microstructured biocrystal piezoelectric flexible electronic device, its preparation method and application, which can be used for real-time monitoring of human movement. Summary of the Invention: The purpose of this invention is to address the shortcomings of existing technologies by providing a microstructured biocrystal piezoelectric flexible electronic device, its fabrication method, and its applications, thereby overcoming the limitations of existing flexible electronic devices in terms of material biocompatibility and structural design.
[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: (I) This invention provides a method for preparing a microstructured biocrystal piezoelectric flexible electronic device, comprising the following steps: A polyvinyl alcohol solution and a glycine solution were mixed, and then PEDOT:PSS solution and gelatin were added and stirred until homogeneous to obtain a mixed solution. The mixed solution was dropped into a template with a porous structure, heated for a period of time, and then cooled to obtain a microstructured biocrystal layer. A polyurethane prepolymer solution was dropped onto the upper surface of the microstructured biocrystal layer, and a silica positive structure template was placed on the upper surface of the polyurethane prepolymer solution. Using capillary force, the polyurethane prepolymer solution was allowed to wet the silica positive structure template, fully wetting the voids of the silica nanoparticles in the positive structure template. Subsequently, the polyurethane prepolymer was cured by solvent evaporation. Finally, the silica positive structure template was etched to obtain a microstructured biocrystal piezoelectric flexible electronic device.
[0006] Furthermore, the volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:1, the concentration of the polyvinyl alcohol solution is 10% w / v, and the concentration of the glycine solution is 10% w / v; in the mixed solution, the concentration of PEDOT:PSS is 1~1.3 wt%, and the concentration of gelatin is 0.75 g / mL.
[0007] Furthermore, after mixing the polyvinyl alcohol solution and glycine solution, the stirring temperature is 60°C and the stirring time is 1 h; after adding PEDOT:PSS solution and gelatin, the stirring temperature is 70°C and the stirring time is 24 h.
[0008] Furthermore, after the mixed solution is added dropwise to the template, the heating temperature is 70°C and the heating time is 6 hours.
[0009] Furthermore, the polyurethane prepolymer solution is obtained by dissolving polyurethane in N,N-dimethylformamide and stirring at 75°C, with a polyurethane concentration of 20 wt%.
[0010] Furthermore, in the template with the cavity structure, the cavity structure is distributed in an array, and the cavity structure is a variable diameter cylindrical structure with a bottom diameter of 330μm, a tip diameter of 100μm, and a height of 600μm; the template is coated with a platinum electrode of about 100nm.
[0011] Furthermore, the solvent evaporation method is carried out at 75°C. After the solvent evaporates, the polyurethane film layer connects the microstructured biocrystal layer with the silica positive structure template.
[0012] Furthermore, the method for preparing the positive silica structure is as follows: prepare a 20wt% silica ethanol solution, and through solvent evaporation, self-assemble silica nanoparticles on a glass slide to obtain a positive silica structure template; the particle size of the silica nanoparticles is 250nm.
[0013] Furthermore, hydrofluoric acid is used to etch the silicon dioxide positive structure template. During the etching process, contact with the microstructured biocrystal layer must be avoided to obtain a microstructured biocrystal piezoelectric flexible electronic device.
[0014] (ii) The present invention also provides a microstructured biocrystal piezoelectric flexible electronic device prepared by the above preparation method, comprising an inverse opal structure layer, a polyurethane film layer and a microstructured biocrystal layer arranged sequentially from top to bottom; the inverse opal structure layer is prepared by a sacrificial template and exhibits a bright structural color behavior; the microstructured biocrystal layer is a micron-scale microstructure array obtained by template replication, wherein the addition of a conductive network helps to obtain a more stable and sensitive piezoelectric signal feedback.
[0015] (III) This invention also provides the application of the microstructured biocrystal piezoelectric flexible electronic device prepared by the above preparation method in the preparation of a real-time human motion monitoring device. The beneficial effects of this invention are: (1) The microstructured biocrystal piezoelectric flexible electronic device provided by this invention has a sandwich structure, with a polyurethane inverse opal structure as the top layer, a polyurethane film as the middle layer, and a microstructured biocrystal as the bottom layer. The glycine crystals in the microstructured biocrystal layer exhibit oriented alignment, displaying piezoelectric properties. On the one hand, the morphology of the microstructure enhances the piezoelectric sensitivity of the flexible electronic device; on the other hand, the addition of the conductive network improves the strength and stability of the piezoelectric output signal. Due to the presence of the flexible polyurethane middle layer, the microstructured biocrystal flexible electronics exhibit strong adaptability and can withstand mechanical behaviors such as bending and compression. The polyurethane inverse opal structure layer endows the microstructured biocrystal flexible electronics with vibrant structural color behavior, exhibiting visual and interactive structural color changes when facing external stimuli.
[0016] (2) The microstructured biocrystal piezoelectric flexible electronic device provided by the present invention has dual sensing performance of piezoelectric response and visual monitoring, and can fit well with the skin to realize real-time monitoring and sensing of human movement.
[0017] (3) The microstructured biocrystal piezoelectric flexible electronic device provided by the present invention has diverse functions, dual signal response sensitivity, stability and reliability, and provides a new idea for the development of flexible electronic devices. Attached image description: Figure 1 This is a schematic diagram of the fabrication process of the microstructured biocrystal flexible electronic device of the present invention; Figure 2 These are piezoelectric performance characterization diagrams of the microstructured biocrystal flexible electronic devices prepared in Examples 1-6; Figure 3These are structural color sensing characterization images of the microstructured biocrystal flexible electronic device prepared in Example 1; where a is a graph showing the change in structural color with pressure; and b is a graph showing the change in reflection peak shift value with pressure. Figure 4 The graph shows the results of real-time monitoring of human movement using the microstructured biocrystal flexible electronic device prepared in Example 1; where a is the voltage change curve of finger touch action; b is the voltage change curve of knee bending action; c is the reflection peak change graph of finger touch action; and d is the reflection peak change graph of knee bending action. Detailed implementation method: To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the reagents, methods, and equipment used are conventional reagents, methods, and equipment in this technical field.
[0020] Example 1 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, comprising, from top to bottom, an inverse opal structure layer, a polyurethane film layer, and a microstructured biocrystal layer. The inverse opal structure layer is fabricated using a sacrificial silica positive structure template, exhibiting vibrant structural color behavior. The microstructured biocrystal layer is a micrometer-scale microstructure array replicated using a template; the addition of a conductive network helps to obtain more stable and sensitive piezoelectric signal feedback.
[0021] Its preparation method specifically includes the following steps: Step 1: Prepare a template with an ordered micro-array cavity structure. In the template, the cavity structure is distributed in an array and is a variable diameter cylindrical structure with a bottom diameter of 330 μm, a tip diameter of 100 μm, and a height of 600 μm.
[0022] Step 2: Dissolve polyvinyl alcohol powder in deionized water and heat and stir at 85°C for 3 hours to form a homogeneous solution, obtaining a 10% w / v polyvinyl alcohol solution; dissolve glycine powder in deionized water to prepare a 10% w / v glycine solution. Mix the polyvinyl alcohol solution and glycine solution at a volume ratio of 1:1, and stir the mixture at 60°C for 1 hour to obtain a homogeneous solution. Add 1.3 wt% PEDOT:PSS solution and 0.75 g / mL gelatin powder to the mixture, and stir at 70°C for 24 hours to obtain a homogeneous mixed solution.
[0023] Step 3: The mixed solution obtained in Step 2 is dropped into the template with the microarray cavity structure from Step 1. Vacuum pressure is used to allow the homogeneous solution to permeate the cavities of the template. The negative mold containing the homogeneous solution is placed in a 70°C environment for 6 hours. The solution gradually evaporates and forms crystals. After cooling to room temperature, a microstructured biocrystal layer is formed inside the template. A platinum electrode with a thickness of about 100 nm is then sprayed onto the surface of the microstructure.
[0024] Step 4: Dissolve polyurethane in N,N-dimethylformamide (DMF) and stir at 75°C to obtain a polyurethane prepolymer solution with a concentration of 20 wt%.
[0025] Step 5: Disperse silica nanoparticles with a particle size of 250 nm uniformly in an ethanol solution to prepare a 20 wt% silica ethanol solution. Through solvent evaporation, the silica nanoparticles self-assemble on a glass slide to obtain a silica positive structure template.
[0026] Step Six: Drop the polyurethane prepolymer solution prepared in Step Four onto the surface of the microstructured biocrystal layer formed in Step Three. Then, flip the silica positive structure template obtained in Step Five and place it above the polyurethane prepolymer solution. Utilizing capillary action, the polyurethane prepolymer solution fully wets the voids in the silica nanoparticles within the positive structure template. The polyurethane prepolymer is cured using a solvent evaporation method at 75°C. After the DMF solution has gradually and completely evaporated, the polyurethane film layer connects the microstructured biocrystal layer to the silica positive structure template. Finally, hydrofluoric acid is used to etch the silica positive structure template, avoiding contact with the microstructured biocrystal layer during the etching process, thereby obtaining a microstructured biocrystal piezoelectric flexible electronic device.
[0027] like Figure 1As shown, 1 is a mixed solution composed of polyvinyl alcohol, glycine, PEDOT:PSS, and gelatin; 2 is a template with an ordered microarray cavity structure; 3 is the self-assembled crystallization of the mixed solution after solvent evaporation; 4 is a DMF solution containing polyurethane; 5 is a polyurethane prepolymer solution that fully impregnates the silica positive structure template; 6 is the connection between the microstructured biocrystal layer and the positive structure template after solvent evaporation and curing of the polyurethane thin film layer, followed by etching to obtain an inverse opal structure; 7 is the microstructured biocrystal piezoelectric flexible electronic device obtained after final demolding.
[0028] Example 2 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, which is prepared using the same method as the previous embodiment, except that the volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:1 in this embodiment.
[0029] Example 3 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, which is prepared using the same method as the previous embodiment, except that the volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:1.5 in this embodiment.
[0030] Example 4 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, which is prepared using the same method as the previous embodiment, except that the volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:2 in this embodiment.
[0031] Example 5 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, which is prepared using the same method as the previous embodiment, except that the volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:0.5 in this embodiment.
[0032] Example 6 This embodiment provides a microstructured biocrystal piezoelectric flexible electronic device, which is prepared using the same method as the previous embodiment, except that the volume ratio of the polyvinyl alcohol solution to the glycine solution is 1.5:0.5.
[0033] Effect test The piezoelectric properties and structural color sensing properties of the microstructured biocrystal flexible electronic device prepared by the above method were characterized.
[0034] 1. Characterization of piezoelectric properties: Considering the influence of glycine content on piezoelectric properties, this invention prepared and studied the effect of different glycine contents on the piezoelectric properties of flexible electronic devices with microstructured biocrystals. To this end, the glycine content was controlled by adjusting the mixing ratio of polyvinyl alcohol solution and glycine solution, as described in Examples 1-6. The flexible electronic devices with different glycine contents from Examples 1-6 were pressed with the same force, and the changes in their piezoelectric output signals during this process were recorded.
[0035] The results showed that as the ratio of polyvinyl alcohol to glycine increased to 1:1.5, the voltage output also increased; further increasing the ratio to 2:1 resulted in a decrease in output voltage. Figure 2 This may be because a higher glycine content is detrimental to crystal continuity.
[0036] 2. Characterization of structural color sensing performance: The structural color sensing performance was characterized using the microstructured biocrystal flexible electronics prepared in Example 1 as an example.
[0037] The polyurethane inverse opal structural layer exhibits structural color behavior. The color sensing capability of the microstructured biocrystal flexible electronic device was tested by adjusting mechanical deformation. Optical photographs were taken in real time during the gradual pressing of the microstructured biocrystal flexible electronic device, and changes in the material's characteristic reflectance were measured using a fiber optic spectrometer. The results are as follows: Figure 3 As shown, this indicates that a structural color change that can be observed with the naked eye is possible. The reflection peak exhibits a blue shift trend, with the color changing from orange-red to blue-green. Figure 3 a), and at the same time, the quantitative results were studied, and the change in the reflection peak shift value was approximately 40 nm ( Figure 3 b).
[0038] 3. Real-time monitoring of human movement Taking the microstructured biocrystal flexible electronics prepared in Example 1 as an example, it was used for real-time monitoring of human movement, as detailed below: Flexible electronic devices with microstructured biocrystals are fixed to different joints in the human body to monitor movements including finger touch and knee flexion. During joint movement, the system collects electrical signal outputs in real time and extracts corresponding characteristic reflection peaks.
[0039] The results are as follows Figure 4 As shown, experimental results demonstrate that this microstructured biocrystal can provide stable and reliable electrical signals, effectively recognizing rapid and slight finger touches. Figure 4 a). As the range of motion increases, such as when the knee is bent, the piezoelectric signal strengthens accordingly, and exhibits consistent response characteristics at different motion frequencies. Figure 4b). Simultaneously, this flexible device also possesses real-time visual color sensing capabilities; the reflection peak shifts accordingly with the movement state, thereby synchronously revealing human motion information. Figure 4 c-4d).
[0040] The above results demonstrate that the microstructured biocrystal flexible electronic device prepared in this invention can effectively monitor human movement by working in conjunction with visual sensing through real-time piezoelectric signal output, providing new ideas and possibilities for the development of a new generation of intelligent, convenient, and efficient flexible electronic devices.
[0041] This invention utilizes glycine, a biocrystalline form, which not only possesses excellent biocompatibility and biodegradability but also can form a regular crystal structure through a self-assembly process, exhibiting significant piezoelectric properties and generating stable electrical signal output under mechanical stimulation. Furthermore, the introduction of a conductive network helps form a three-dimensional conductive pathway, greatly reducing internal impedance and charge recombination losses, thereby significantly improving the strength and stability of the piezoelectric output signal.
[0042] This invention overcomes the limitations of existing flexible electronic devices in terms of material biocompatibility and structural design, proposing a method for fabricating piezoelectric flexible electronic devices based on microstructured biocrystals. This method not only focuses on the controllable construction of microstructures but also strives to achieve efficient integration of the device on a flexible substrate and diversify its sensing functions. By optimizing the array morphology design and combining it with a conductive network, the signal output strength and operational stability of the device under dynamic mechanical loads are effectively improved. The sensor system constructed by this invention can accurately capture minute deformations generated during human movement and synchronously convert them into electrical signals and identifiable optical signals, thereby enabling real-time and continuous monitoring of motion status.
[0043] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.
Claims
1. A method for fabricating a microstructured biocrystal piezoelectric flexible electronic device, characterized in that, Includes the following steps: Mix polyvinyl alcohol solution and glycine solution, add PEDOT:PSS solution and gelatin, stir well to obtain a mixed solution; The mixed solution was dropped into a template with a porous structure, heated for a period of time and then cooled to obtain a microstructured biocrystal layer. A polyurethane prepolymer solution was dropped onto the surface of a microstructured biocrystal layer. A silica positive structure template was placed on the surface of the polyurethane prepolymer solution. The polyurethane prepolymer was then cured by solvent evaporation. Finally, the silica positive structure template was etched to obtain a microstructured biocrystal piezoelectric flexible electronic device.
2. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, The volume ratio of the polyvinyl alcohol solution and the glycine solution is 1:1, the concentration of the polyvinyl alcohol solution is 10% w / v, and the concentration of the glycine solution is 10% w / v. In the mixed solution, the concentration of PEDOT:PSS is 1~1.3 wt%, and the concentration of gelatin is 0.75 g / mL.
3. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, The polyvinyl alcohol solution and glycine solution were mixed and stirred at 60°C for 1 hour. After adding PEDOT:PSS solution and gelatin, the stirring temperature was 70℃ and the stirring time was 24 h.
4. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, After the mixed solution is added dropwise to the template, the heating temperature is 70°C and the heating time is 6 hours.
5. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, The polyurethane prepolymer solution is obtained by dissolving polyurethane in N,N-dimethylformamide and stirring at 75°C, with a polyurethane concentration of 20 wt%.
6. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, In the template with the cavity structure, the cavity structure is distributed in an array, and the cavity structure is a variable diameter cylindrical structure with a bottom diameter of 330μm, a tip diameter of 100μm, and a height of 600μm; The template is coated with a platinum electrode of about 100 nm.
7. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, The solvent evaporation method is carried out at 75°C. After the solvent evaporates, the polyurethane film layer connects the microstructured biocrystal layer with the silica positive structure template.
8. The method for fabricating the microstructured biocrystal piezoelectric flexible electronic device according to claim 1, characterized in that, The method for preparing the positive silica structure is as follows: prepare a silica ethanol solution, and through solvent evaporation, self-assemble silica nanoparticles on a glass slide to obtain a silica positive structure template; the particle size of the silica nanoparticles is 250 nm.
9. A microstructured biocrystal piezoelectric flexible electronic device prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the microstructured biocrystal piezoelectric flexible electronic device prepared by the preparation method according to any one of claims 1 to 8 in the preparation of a real-time human motion monitoring device.