A polyionic elastomer pressure sensor of a biomimetic microstructured dielectric layer
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2026-03-31
- Publication Date
- 2026-05-29
AI Technical Summary
Existing flexible pressure sensors struggle to maintain high sensitivity and linear response over a wide pressure range, limiting their applicability in high-precision applications.
We designed a microconical dielectric layer with a Fibonacci spiral arrangement, combined with a polyion-elastomer material, and by mimicking the distribution of sunflower seeds, we ensured that the dielectric layer triggered microstructure contacts step by step under different pressures, thus optimizing the capacitance changes of the ion-electron double layer.
It achieves high sensitivity and stability over a wide pressure range, overcomes the response saturation and linearity degradation problems of traditional flexible sensors, and provides greater linearity and higher sensitivity.
Smart Images
Figure CN121933159B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sensor technology, specifically to a biomimetic microstructured dielectric layer polyion elastomer pressure sensor. The microstructured dielectric layer, designed based on biomimetic principles and arranged in a Fibonacci spiral, is a flexible sensor. Background Technology
[0002] With the rapid development of smart wearable devices and sensor technology, flexible pressure sensors, as key components for sensing changes in external pressure, have shown broad application potential in fields such as health monitoring, robotic tactile systems, and the Internet of Things. These sensors achieve precise environmental interaction by capturing pressure changes, and their performance directly determines the reliability and functionality of related devices. However, existing flexible pressure sensors still face technical bottlenecks in terms of sensitivity, linear response, and long-term stability, making it difficult to meet the needs of diverse application scenarios.
[0003] Ion-based flexible sensors are based on the principle of interfacial capacitance. They introduce nanoscale ion-electron double-layer capacitance (EDL) at the electrode interface, utilizing the capacitance change induced by external force to generate an electrical signal output. Although microstructure designs such as microcones, microspheres, and micropillars can achieve high sensitivity in low-pressure ranges, their linear response range is limited, and they are prone to response saturation at higher pressures, leading to a significant decrease in linearity. This limitation prevents the sensor from maintaining stable performance over a wide pressure range, restricting its applicability in high-precision applications.
[0004] If ionized flexible sensors can achieve high linearity over a wide pressure range while maintaining excellent response sensitivity and stability, it will drive the widespread application of polyionized elastomers in various fields such as smart wearable devices, robotic tactile sensing, health monitoring systems, and the Internet of Things. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a biomimetic microstructured dielectric layer polyionoelastic pressure sensor. This sensor utilizes a microconical dielectric layer with a Fibonacci spiral arrangement, higher on the outside and lower on the inside, mimicking the growth pattern of sunflower seeds in nature. This ensures that the upper electrode can progressively trigger contact with the dielectric layer microstructures at different heights when subjected to pressure, thereby maintaining a large linear response over a wide pressure range. Furthermore, this invention selects polyionoelastic as the dielectric layer material, leveraging its tunable composition to achieve an optimized balance between ionic conductivity and mechanical properties. This material not only ensures high sensitivity of the sensor in high-pressure regions but also effectively improves its stability and durability in high-pressure areas.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] A biomimetic microstructured dielectric layer polyion elastomer pressure sensor includes a lower electrode, a dielectric layer, a spacer layer, and an upper electrode stacked sequentially from bottom to top.
[0008] The dielectric layer is a circular flat substrate with a diameter of 8-15 mm and a thickness of 0.2-1 mm, and has n microcones on the side facing the spacer layer.
[0009] The microcones include at least three different height levels, and the maximum height difference between the microcones of different heights does not exceed 200 micrometers. The height of the microcones gradually decreases from the outside to the inside along the circular flat substrate region. The distribution of the center points of the n microcones on the dielectric layer follows a Fibonacci spiral pattern similar to the distribution of sunflower seeds, thereby achieving a uniformly filled array of microcones within the circular region of the dielectric layer.
[0010] The spacer layer is annular and is used to isolate the upper electrode from the dielectric layer, preventing the upper electrode from directly contacting the microcone of the dielectric layer. The outer diameter of the spacer layer is the same as the diameter of the dielectric layer, the ring width is 0.5~1 mm, and the height of the spacer layer is the same as the maximum height of the microcone.
[0011] Furthermore, the number n of the microcones is 50 to 200.
[0012] Furthermore, the number n of the microcones is 50, 100, 150 or 200.
[0013] Furthermore, the microcone is a cone with a diameter of 100-200 micrometers; the minimum height of the microcone is 100-200 micrometers, and the maximum height is 200-300 micrometers.
[0014] Furthermore, the spacer layer is made of polydimethylsiloxane elastomer.
[0015] Furthermore, the dielectric layer is made of polyionomer, which is a cross-linked network structure formed by polyurethane precursor and polymerizable ionic liquid, forming an ion-electron double layer capacitor (EDL) at the electrode-dielectric layer interface. This double layer capacitor can provide very high capacitance, and even a very small pressure can cause a large capacitance change, thus exhibiting high sensitivity.
[0016] Furthermore, the aforementioned biomimetic microstructured dielectric layer polyion elastomer pressure sensor also has an encapsulation layer on the outside of the upper and lower electrodes to provide protection.
[0017] A biomimetic microstructured dielectric layer polyion elastomer pressure sensor includes a lower electrode, a dielectric layer, a spacer layer, and an upper electrode stacked sequentially from bottom to top.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] This invention, for the first time, incorporates biomimetic principles to design a Fibonacci spiral-arranged microconical structure for use in a flexible pressure sensor. Under low pressure, the outermost, taller microcones on the dielectric layer are compressed first, resulting in a change in capacitance. As the pressure increases, the innermost, shorter microcones are compressed. This biomimetic microstructure provides greater compressibility to the dielectric layer, ensuring high sensitivity even under high pressure and significantly improving the sensor's linear response over a wide pressure range. Ultimately, this invention optimizes the change in ion-electron double-layer capacitance by gradually contacting microstructures of different heights under pressure, thereby achieving greater linearity and higher sensitivity, overcoming the common defects of response saturation and linearity degradation in traditional flexible sensor designs. Attached Figure Description
[0020] Figure 1 The image shows a sunflower seed and a diagram illustrating the Fibonacci spiral pattern.
[0021] Figure 2 This is a schematic diagram showing the azimuth angle distribution of the center point of the microcone in the polar coordinate system.
[0022] Figure 3 This describes the fabrication process of the microstructured dielectric layer and sensor in this invention.
[0023] Figure 4 The figures show cross-sectional views and corresponding top views of the microconical structures in Examples 1-4.
[0024] Figure 5 This is an optical image of the microstructured dielectric layer in Example 1.
[0025] Figure 6 The sensitivity curve of the polyion elastomer pressure sensor with microstructured dielectric layer in Example 1 is shown. Detailed Implementation
[0026] The present invention will be further described below with reference to embodiments and accompanying drawings.
[0027] Example 1
[0028] A biomimetic microstructured dielectric layer polyion elastomer pressure sensor includes a lower electrode, a dielectric layer, a spacer layer, and an upper electrode stacked sequentially from bottom to top.
[0029] The specific preparation process is as follows: Figure 3 As shown:
[0030] Step 1: Microstructure design.
[0031] The microstructure design in this embodiment was completed using modeling software. The dielectric layer has a diameter of 10 mm and a thickness of 0.5 mm, and microcones are arranged in a Fibonacci spiral pattern. The microcones (which are cones) are arranged at a golden angle, and there are 50 microcones arranged on the surface of the dielectric layer. This ensures that the microstructures at different heights can gradually contact each other under different pressures, optimizing the response characteristics of the flexible pressure sensor. The height of the microcones gradually decreases from the outside to the inside, with a maximum height of 300 micrometers and a minimum height of 100 micrometers. The diameter of the microcones ranges from 200 micrometers.
[0032] Furthermore, the Fibonacci spiral arrangement of the microcone is specifically as follows:
[0033] Establish a polar coordinate system with the center point of the circular region on the dielectric layer as the origin. For a total of n microcones, the th... The center points of the microcones are numbered in the polar coordinate system as follows: And has a corresponding azimuth angle And satisfy: The azimuth angle is the difference in azimuth angle between the center point of the microcone and the center of the circle, such as... Figure 2 As shown, rather than the tilt angle or rotational orientation angle of the microcone body.
[0034] in =1, 2, 3, …n; For the golden corner, ≈137.5° Take its range from 0° to 360° with Equivalent angle value; and Indicates the center point of adjacent serial number microcones. and The azimuth difference relative to the origin is constant. Among them, adjacent refers to adjacent sequence numbers. and It is not the nearest neighbor in the sense of planar distance.
[0035] The distribution of the center points of the microcones ultimately resembles the Fibonacci spiral pattern of sunflower seeds, thus achieving a uniformly filled array of microcones within the circular region of the dielectric layer. Figure 1 The image shows a sunflower seed and a diagram illustrating the Fibonacci spiral arrangement. The microcones are arranged at a golden angle (approximately 137.5°), a configuration that helps optimize the linear response and sensitivity of the flexible pressure sensor under stress.
[0036] Step 2: Microstructure reverse template design.
[0037] In this embodiment, the anti-template design of the microstructure was performed using modeling software. The anti-template design ensured that the microcones were arranged according to the Fibonacci spiral, and took into account factors such as the size, angle, and spacing of the microcones to accurately reproduce them onto the dielectric layer surface. The anti-template was then prepared by photopolymerization 3D printing.
[0038] Step 3: Preparation of polyionoelastic (polyurethane-based ionoelastic) with biomimetic microstructured dielectric layer.
[0039] In this embodiment, the polyurethane prepolymer and polymerizable ionic liquid are first mixed at a molar ratio of 15:100, and a photoinitiator is added (the amount of photoinitiator added is 5% of the total mass of the polyurethane prepolymer and polymerizable ionic liquid). Then, the mixture is uniformly injected into the designed microstructure inverse mold to ensure that the material can completely fill the microstructure of the mold.
[0040] After injection, the reverse template is placed in an ultraviolet irradiation device and cured using 405nm wavelength ultraviolet light for 1 minute. After curing, demolding yields a polyurethane-based ionomer dielectric layer with a microconical structure. At this point, the arrangement and size of the microcones have been replicated on the dielectric layer surface and conform to the Fibonacci spiral arrangement design, ensuring high sensitivity and good response of the sensor under different pressures.
[0041] Step 4: Fabrication of a polyion elastomer pressure sensor based on a biomimetic microstructured dielectric layer.
[0042] The polyurethane-based polyionomer material sample prepared in step 3 was used as the sensing layer (dielectric layer), and the following was followed: Figure 3 The structure shown consists of a lower electrode, a dielectric layer, a spacer layer (made of polydimethylsiloxane elastomer), and an upper electrode stacked sequentially from bottom to top, and then encapsulated; a complete flexible pressure sensor is further fabricated, and then relevant tests and characterization are performed.
[0043] Example 2
[0044] Compared to Example 1, this example only changes the number of microcones in step 1 to 100, while keeping other parameters unchanged, and finally obtains a polyion elastomer pressure sensor with a corresponding microstructured dielectric layer.
[0045] Example 2
[0046] Compared to Example 1, this example only changes the number of microcones in step 1 to 150, while keeping other parameters unchanged, and finally obtains a polyion elastomer pressure sensor with a corresponding microstructured dielectric layer.
[0047] Example 3
[0048] Compared to Example 1, this example only changes the number of microcones in step 1 to 200, while keeping other parameters unchanged, and finally obtains a polyion elastomer pressure sensor with a corresponding microstructured dielectric layer.
[0049] Figure 4 The figures show cross-sectional views and corresponding top views of the microconical structures in Examples 1-4. They illustrate the arrangement and size distribution of the microconical structures in this invention, with the height of the microcones gradually changing on the dielectric layer surface. A Fibonacci spiral arrangement is used, with each microcone arranged at a golden angle (approximately 137.5°). The diameter of the microconical structure is 0.5 mm, and they are arranged on a 10 mm wide dielectric layer surface. Different colored microcones represent different height levels.
[0050] Figure 5 This is an optical image of the microstructured dielectric layer in Example 1.
[0051] Figure 6 The sensitivity curve of the polyionomer pressure sensor with a microstructured dielectric layer in Example 1 is shown. The results indicate that the polyionomer pressure sensor with a microstructured dielectric layer maintains good linearity with stress and capacitance changes within a stress range of 350 kPa, and maintains a pressure of 5.3 kPa. −1 High sensitivity.
[0052] As can be seen from the above embodiments, this invention utilizes a microconical dielectric layer with a Fibonacci spiral arrangement, higher on the outside and lower on the inside, mimicking the growth pattern of sunflower seeds in nature. This ensures that the dielectric layer can progressively trigger contact between microstructures of different heights under stress, thereby maintaining a large linear response over a wide pressure range. By progressively contacting microstructures of different heights under pressure, the change in ionic capacitance is optimized, resulting in a greater linearity response and higher sensitivity; overcoming the common defects of response saturation and linearity degradation in traditional flexible sensor designs. This invention can employ microconical designs with different heights and spacings, providing customized performance optimization according to different application requirements. Whether it's linearity over a wide pressure range or sensitivity under high pressure, this invention provides an ideal solution. Furthermore, this invention selects polyionomer as the dielectric layer material, utilizing its tunable composition to achieve an optimized balance between ionic conductivity and mechanical properties; this material not only ensures high sensitivity of the sensor in high-pressure areas but also effectively improves its stability and durability in high-pressure regions.
Claims
1. A biomimetic microstructured dielectric layer polyion elastomer pressure sensor, comprising a lower electrode, a dielectric layer, a spacer layer, and an upper electrode stacked sequentially from bottom to top, characterized in that: The dielectric layer is a circular flat substrate with a diameter of 8-15 mm and a thickness of 0.2-1 mm, and has n microcones on the side facing the spacer layer; The microcones include at least three different height levels, and the maximum height difference between the microcones of different heights does not exceed 200 micrometers. The height of the microcones gradually decreases from the outside to the inside along the circular flat plate substrate area. The distribution of the center points of n microcones on the dielectric layer presents a Fibonacci spiral pattern that mimics the distribution of sunflower seeds, thus achieving a uniformly filled array of microcones within the circular region of the dielectric layer. The Fibonacci spiral arrangement of the microcones is specifically as follows: Establish a polar coordinate system with the center point of the circular region on the dielectric layer as the origin. For a total of n microcones, the th... The center points of the microcones are numbered in the polar coordinate system as follows: And has a corresponding azimuth angle And satisfy: The azimuth angle is the difference in azimuth angle between the center point of the microcone and the center of the circle, not the tilt angle or rotational orientation angle of the microcone body. in =1, 2, 3, …n; For the golden corner, ≈137.5° Take its range from 0° to 360° with Equivalent angle value; and Indicates the center point of adjacent serial number microcones. and The azimuth difference relative to the origin is constant. Among them, adjacent refers to adjacent sequence numbers. and It is not the nearest neighbor in the sense of planar distance; The spacer layer is annular and is used to isolate the upper electrode from the dielectric layer, preventing the upper electrode from directly contacting the microcone of the dielectric layer. The outer diameter of the spacer layer is the same as the diameter of the dielectric layer, the ring width is 0.5~1 mm, and the height of the spacer layer is the same as the maximum height of the microcone.
2. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 1, characterized in that: The number of microcones, n, is 50 to 200.
3. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 2, characterized in that: The number n of the microcones is 50, 100, 150 or 200.
4. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 1, characterized in that: The microcone is a cone with a diameter of 100-200 micrometers; the minimum height of the microcone is 100-200 micrometers, and the maximum height is 200-300 micrometers.
5. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 1, characterized in that: The spacer layer is made of polydimethylsiloxane elastomer.
6. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 1, characterized in that: The dielectric layer is made of polyion-electrode elastomer, and the polyion-electrode elastomer dielectric layer introduces an ion-electrode double layer capacitor (EDL).
7. The polyion elastomer pressure sensor with a biomimetic microstructured dielectric layer as described in claim 1, characterized in that: The upper and lower electrodes are also provided with an encapsulation layer on their outer sides.