A hypersensitive coupling bionic strain sensor and a preparation method thereof

Abstract

The application discloses a kind of hypersensitive coupling bionic strain sensors and preparation method thereof, belong to the field of strain sensor.The specific method is through coupling bionic arthropod crack receptor and helical growth divergent law of sunflower seed, design coupling bionic strain sensor structure, prepare flexible elastic substrate with micro-nano coupling bionic crack array using replication transfer method, and carry out ion sputtering and plate a layer of nano silver film, obtain the resistance layer deposited on flexible elastic substrate and micro-nano coupling bionic crack array.Finally, copper wire electrode is packaged on the surface of resistance layer, and a kind of coupling bionic strain sensor is obtained, which not only has ultrahigh sensitivity, but also good durability, rapid response time and recovery time, simple structure, and excellent performance in all aspects.

Description

Technical Field

[0001] This invention relates to the field of strain sensors, specifically to an ultrasensitive coupled biomimetic strain sensor and its fabrication method. Background Technology

[0002] In recent years, flexible electronic devices have gradually become a research hotspot, such as wearable devices, electronic skin, and robots. Flexible strain sensors are an indispensable type of sensor in flexible electronic devices. Improving the design and fabrication techniques of flexible strain sensors can enhance their performance and thus promote the development of flexible electronics. Sensitivity is one of the most critical performance characteristics of flexible strain sensors. Improving its sensitivity can broaden the sensor's detection range, enabling it to detect very weak strain signals, such as human pulse and heart rate. With the rapid development of bionics, applying bionic principles to the design of flexible strain sensors can not only enrich the sensing mechanism but also improve the performance of strain sensors. Therefore, this paper proposes a hypersensitive coupled bionic strain sensor and its fabrication method. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes an ultrasensitive coupled biomimetic strain sensor and its fabrication method.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A hypersensitive coupled biomimetic strain sensor, comprising:

[0006] Flexible substrate;

[0007] A micro-nano coupled biomimetic crack array is disposed on the flexible substrate. The micro-nano coupled biomimetic crack array consists of N first arc lines and N second arc lines arranged in a circle with the same center; where N is an integer greater than 0; the micro-nano coupled biomimetic crack array refers to a micro-nano scale crack array designed with two biological characteristics coupled in a biomimetic manner.

[0008] A resistive layer is deposited on the flexible substrate and the micro / nano coupled biomimetic crack array;

[0009] Electrodes are disposed on the resistive layer.

[0010] Furthermore, the second arc and the first arc are mirror symmetrical.

[0011] Furthermore, the arc of the micro-nano coupled biomimetic crack array is composed of three points: the first point is the geometric center point, the second point is at a distance of h from the geometric horizontal center line, and the third point is at a distance of w from the geometric vertical center line.

[0012] Furthermore, the sensor is a cuboid, satisfying c = 0.35a, r = 0.05a, and a > 10d;

[0013] Where c is the chord length of each arc of the micro-nano coupled biomimetic crack array; a is the side length of the sensor; d is the height of the sensor; and r is the radius of the circular region at the center of the pattern formed by the first arc and the second arc.

[0014] Furthermore, the material of the flexible substrate is one or more of the following: epoxy resin, polyethylene, polyvinylidene fluoride, polypropylene, polystyrene, polysulfone ether, polyimide, polyamide, thermoplastic polyurethane, polyethylene terephthalate, styrene-butadiene-styrene block copolymer, natural rubber, nitrile rubber, polydimethylsiloxane, styrene-based thermoplastic elastomers, thermoplastic vulcanized rubber, silicone, and biodegradable fossil-based polymer Ecoflex.

[0015] Furthermore, the material of the resistive layer is one or more of the following: gold nanoparticles, silver nanoparticles, copper nanoparticles, platinum nanoparticles, carbon nanotubes, graphene, carbon black, carbon fiber, aluminum-boron alloy, aluminum-chromium alloy, iron-manganese alloy, aluminum-chromium-yttrium alloy, and silver-copper-palladium alloy.

[0016] Furthermore, the electrode is made of one or more of the following materials: gold, silver, copper, iron, graphite, steel, copper, copper-tungsten alloy, silver-tungsten alloy, brass, and cast iron.

[0017] The present invention also provides a method for fabricating a hypersensitive coupled biomimetic strain sensor as described in any of the preceding claims, comprising the following steps:

[0018] A model of the biomimetic strain sensor was created using 3D modeling software, and then the structural parameters of the sensor and the micro-nano coupled biomimetic crack array were determined by simulation using finite element analysis software.

[0019] A flexible substrate with a micro-nano coupled biomimetic crack array was prepared using a replication transfer method.

[0020] The flexible substrate is placed in an ion sputtering instrument to deposit a resistive layer on the flexible substrate and the micro-nano coupled biomimetic crack array.

[0021] The sensor is obtained by attaching copper wire electrodes to the surface of the resistive layer with copper tape.

[0022] The beneficial effects of this invention are:

[0023] This invention designs a sensor structure by coupling a biomimetic arthropod crack receptor with the spiral divergent growth pattern of sunflower seeds. The resulting biomimetic strain sensor has ultra-high sensitivity and very fast response and recovery times. Moreover, the circular blank space at the center of the micro-nano coupled biomimetic crack array can avoid stress concentration and improve the durability of the biomimetic strain sensor. The ultrasensitive biomimetic strain sensor of this invention has a simple structure, is easy to fabricate, and has excellent performance in all aspects. Attached Figure Description

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] Figure 1 This is a diagram of the micro / nano-coupled biomimetic crack array structure of this application;

[0026] Figure 2 This is a schematic diagram of the fabricated ultrasensitive coupled biomimetic strain sensor of this application;

[0027] Figure 3 This is a super-depth-of-field morphology image of the micro-nano coupled biomimetic crack of the supersensitive coupled biomimetic strain sensor of this application.

[0028] Figure 4 This is a test graph showing the resistance change rate as a function of strain for the hypersensitive coupled biomimetic strain sensor of this application.

[0029] Figure 5 The graph shows the number of cycles for durability testing of the hypersensitive coupled biomimetic strain sensor of this application at a strain of 0.1764%.

[0030] Figure 6 The graph shows the response time and recovery time of the hypersensitive coupled biomimetic strain sensor of this application at a strain of 0.4%. Detailed Implementation

[0031] 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, and 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.

[0032] This invention provides a supersensitive coupled biomimetic strain sensor, comprising a flexible substrate, a micro / nano coupled biomimetic crack array on the surface of the flexible substrate, a resistive layer deposited on the flexible substrate and the micro / nano coupled biomimetic crack array, and electrodes disposed on the resistive layer;

[0033] The micro-nano coupled biomimetic crack array is composed of N first arc lines 1 and N second arc lines 2, with the first arc lines 1 and the second arc lines 2 arranged in a circle with the same center, and N is an integer greater than 0.

[0034] Example

[0035] Fabrication of a hypersensitive coupled biomimetic strain sensor

[0036] (1) A three-dimensional model of the biomimetic strain sensor was constructed using SOLIDWORKS software. In this embodiment, N=12. The design parameters were optimized through ANSYS finite element simulation to obtain the design parameters of the micro-nano coupled biomimetic crack array structure of the biomimetic strain sensor with excellent performance in all aspects. The arc of the micro-nano coupled biomimetic crack array is composed of three points: the first point is the geometric center point, the second point is h away from the geometric horizontal center line, and the third point is w away from the geometric vertical center line; in this embodiment, h=0.22 and w=0.16. The length, width, and height of the biomimetic strain sensor model are 1*1*0.1mm respectively. Figure 1 As shown.

[0037] (2) The optimal structural design parameters obtained in (1) are used to draw a micro-nano coupled biomimetic array pattern using CAD. The drawn pattern is then imported into a paper cutter to cut out the coupled biomimetic structure on a PET film. The length, width and height of the PET film are 25*25*1mm.

[0038] (3) Place the PET sheet obtained in (2) on the substrate of the spin coater, and evenly spin coat the liquid epoxy resin AB glue onto the surface of the PET sheet. The spin coater speed is 100 r / min, and the spin coat takes about 60 seconds. After spin coat, place it in a vacuum drying oven and evacuate for 20 minutes to remove air bubbles from the spin-coated epoxy resin AB glue. Cure at 70°C for about 2 hours. Liquid epoxy resin AB glue ratio: A:B = 3:1.

[0039] (4) Peel off the epoxy resin AB glue cured in (3) from the PET board to obtain an epoxy resin model with protruding micro-nano coupled biomimetic array pattern.

[0040] (5) Place the epoxy resin model obtained in (4) onto the substrate of the spin coater, and uniformly spin coat the liquid PDMS onto the surface of the epoxy resin model. The spin coater speed is 100 r / min, and the spin coat takes about 60 seconds. After spin coat, place it in a vacuum drying oven and evacuate for 20 minutes to remove air bubbles from the spin-coated PDMS. Cure at 80°C for about 2-3 hours. Liquid PDMS ratio: precursor: curing agent = 10:1.

[0041] (6) Peel off the PDMS cured in (5) from the epoxy resin model to obtain a PDMS flexible substrate with a micro-nano coupled biomimetic crack array. The length, width and height of the flexible substrate are approximately 25*25*1mm.

[0042] (7) The flexible substrate obtained in (6) is placed in an ion sputtering apparatus to deposit a film. The film material is silver nanoparticles, and the thickness is approximately 100 nm, resulting in a resistive layer deposited on the flexible substrate and the micro / nano-coupled biomimetic crack array. Finally, copper wire electrodes are attached to the surface of the resistive layer with copper tape to obtain an ultrasensitive biomimetic strain sensor, such as... Figure 2 As shown.

[0043] The structure of the hypersensitive coupled biomimetic strain sensor prepared in this embodiment was characterized. The morphology of the micro / nano coupled biomimetic crack array was characterized using a super depth-of-field digital 3D video microscope, such as... Figure 3 As shown, the crack depth is approximately 80 μm, and each crack has a roughly equal depth.

[0044] Performance testing of the fabricated hypersensitive coupled biomimetic strain sensor

[0045] Sensitivity (GF) test: such as Figure 4 As shown, the fabricated hypersensitive coupled biomimetic strain sensor exhibits extremely high sensitivity. In the first stage, when the strain is less than 0.46%, the maximum sensitivity is approximately 4000. In the second stage, when the strain is greater than 0.46%, the sensitivity suddenly surges to a maximum of approximately 60000, indicating that the fabricated coupled biomimetic strain sensor has extremely high sensitivity. Furthermore, even at a very low strain of 0.058%, there is still a resistance change, with a sensitivity of approximately 2014.

[0046] Durability testing: such as Figure 5 As shown, under cyclic stretching with a strain of 0.18%, the resistance change rate of the hypersensitive coupled bionic strain sensor remained relatively stable during 7000 cycles, indicating that the prepared hypersensitive coupled bionic strain sensor has good durability and can maintain a stable and good working state over a long period of time.

[0047] Response time and recovery time tests: such as Figure 6 As shown, with a strain of 0.40%, the response time is 104 ms and the recovery time is 112 ms. Both the response and recovery times are relatively fast, indicating that the fabricated hypersensitive coupled biomimetic strain sensor has a rapid response and good performance.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A hypersensitive coupled biomimetic strain sensor, characterized in that, include: Flexible substrate; A micro-nano coupled biomimetic crack array is disposed on the flexible substrate. The micro-nano coupled biomimetic crack array is composed of N first arc lines (1) and N second arc lines (2). The first arc lines (1) and the second arc lines (2) are arranged in a circle with the same center. The second arc lines (2) and the first arc lines (1) are mirror symmetrical. N is an integer greater than 0. The first arc (1) and the second arc (2) intersect each other; The sensor is a cuboid, satisfying c = 0.35a, r = 0.05a and a > 10d; where c is the chord length of each arc of the micro-nano coupled biomimetic crack array; a is the side length of the sensor; d is the height of the sensor; and r is the radius of the circular region at the center of the pattern formed by the first arc (1) and the second arc (2). A resistive layer is deposited on the flexible substrate and the micro / nano coupled biomimetic crack array; Electrodes are disposed on the resistive layer.

2. The ultrasensitive coupled biomimetic strain sensor according to claim 1, characterized in that, The flexible substrate is made of one or more of the following materials: epoxy resin, polyethylene, polyvinylidene fluoride, polypropylene, polystyrene, polysulfone ether, polyimide, polyamide, thermoplastic polyurethane, polyethylene terephthalate, styrene-butadiene-styrene block copolymer, natural rubber, nitrile rubber, polydimethylsiloxane, styrene-based thermoplastic elastomers, thermoplastic vulcanized rubber, silicone, and biodegradable fossil-based polymer Ecoflex.

3. The ultrasensitive coupled biomimetic strain sensor according to claim 1, characterized in that, The resistive layer is made of one or more of the following materials: gold nanoparticles, silver nanoparticles, copper nanoparticles, platinum nanoparticles, carbon nanotubes, graphene, carbon black, carbon fiber, aluminum-boron alloy, aluminum-chromium alloy, iron-manganese alloy, aluminum-chromium-yttrium alloy, and silver-copper-palladium alloy.

4. The ultrasensitive coupled biomimetic strain sensor according to claim 1, characterized in that... The electrode is made of one or more of the following materials: gold, silver, copper, iron, graphite, steel, copper, copper-tungsten alloy, silver-tungsten alloy, brass, and cast iron.

5. A method for fabricating a hypersensitive coupled biomimetic strain sensor as described in any one of claims 1 to 4, characterized in that... This includes the following steps: A model of the biomimetic strain sensor was created using 3D modeling software, and then the structural parameters of the sensor and the micro-nano coupled biomimetic crack array were determined by simulation using finite element analysis software. A flexible substrate with a micro-nano coupled biomimetic crack array was prepared using a replication transfer method. The flexible substrate is placed in an ion sputtering instrument to deposit a resistive layer on the flexible substrate and the micro-nano coupled biomimetic crack array. The sensor is obtained by attaching copper wire electrodes to the surface of the resistive layer with copper tape.

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