CN116447967A - High-sensitivity and high-linearity collaborative bionic flexible strain sensor and manufacturing method thereof - Google Patents
High-sensitivity and high-linearity collaborative bionic flexible strain sensor and manufacturing method thereof Download PDFInfo
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/12—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
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- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
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- B05D7/52—Two layers
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- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention discloses a high-sensitivity and high-linearity collaborative bionic flexible strain sensor and a manufacturing method thereof, wherein the strain sensor sequentially comprises a flexible substrate, a conductive functional layer and an electrode from bottom to top; a fold structure is distributed on one surface of the flexible matrix near the conductive functional layer; the conductive functional layer is formed by stacking a plurality of layers of different materials. The invention adopts a template method to prepare the flexible matrix with the fold structure. When the bionic flexible sensor is subjected to external stress or strain, the size and shape of the surface fold structure of the sensor are changed, and micro-cracks can be generated by micro-deformation, so that the electrical property of the sensor is changed. The combination of microcracks and pleated structures provides high sensitivity and high linearity characteristics for biomimetic sensors with large strain stretching capabilities. The sensor of the invention has high sensitivity, high linearity and large strain characteristics.
Description
Technical Field
The invention relates to the technical field of strain sensors, in particular to a high-sensitivity and high-linearity collaborative bionic flexible strain sensor and a manufacturing method thereof.
Background
The flexible strain sensor with ductility and stretchability has a far-reaching application prospect in the fields of electronic skin, human activity monitoring, voice recognition, intelligent robots and the like because of being capable of being used in a conformal way on a curved surface. In the development of flexible strain sensors, the improvement of performance parameters such as working range, sensitivity, linearity, stability and the like is a focus of attention of researchers. While flexible strain sensor layers based on various sensing structures, conductive materials, are endless, achieving a balance between high sensitivity, linearity, and stretchability remains very challenging. Taking a resistive flexible strain sensor as an example, a flexible sensor with large stretchability (i.e., a wide working range) generally has low sensitivity, while a flexible strain sensor with high sensitivity has a small working range. In addition, due to the participation of high molecular polymers in the flexible strain sensor, the working principle of the resistance sensor is generally based on seepage theory, tunneling theory and the like, so that the signal output of the sensor usually appears in a parabolic curve-like form, the linearization is poor, and the resistance sensor can only be fitted in a piecewise manner. Bimodal tensile strain sensors based on biomimetic elicited carbon nanotubes/graphene/silicone rubber/ferroferric oxide nanocomposites are described in the paper Bioinspired Dual-Mode Stretchable Strain Sensor Based on Magnetic Nanocomposites for Strain/Magnetic Discrimination (Xiaohui Guo, et al, small,2023,19 (1): 2205316), with a sensitivity of only 8.43 in a strain amount of 0-120%; the sensor output is not linear in the 0-160% strain range, but can only be fitted in piecewise linearization, with a linearity of 0.96 in the 0-120%. A flexible strain sensor made of composite materials is described in the article Ultra-sensitive and resilient compliant strain gauges for soft machines (Oluwaseun A. Aromi, et al, nature,2020, 587:219-224), which has a linearity of up to 0.98 in a strain range of-1.5% to-3%, a sensitivity of up to 9400, but a working range of only about 3%, and a non-linearity in a strain range of 0 to-1.5%. To achieve multi-performance synergy of the sensor, graphitized carbon black, a conductive material, is embedded in an insulating frame of defatted cellulose nanofibers and encapsulated in an elastic polymer, as in chapter Wide Linear Range Strain Sensor Enabled by the Non-Newtonian Fluid for Bio-Signals Monitoring (WeiD, et al advanced Engineering Materials,2022,24 (10): 2200100), achieving a broad linear range, but only a sensitivity (GF) of 5.47.
With the rise of the nanometer conductive material film, the performance of the sensor can be obviously improved by utilizing the surface microstructure of the conductive film, particularly, the sensor is represented by a crack structure, and the aim of greatly improving the sensitivity is fulfilled by a conductive mechanism of breaking a conductive path under a tiny strain. However, the crack structure brings high sensitivity while also presenting challenges for the stretching range. Therefore Kim et al sputter metallic Pt nanoparticles onto the pretreated polymer substrate surface and form a crack structure by stretching, achieving high sensitivity, but the stretcher is only 2% and the crack structure on the film surface is very ductile to break when stretched, the strain sensor will respond to the applied strain in a nonlinear manner, resulting in poor linearity of the sensor [ KangD, et al nature,2014,516,222-226]. The fold structure has unique natural advantages, such as large stretchability, large specific surface area, anisotropy and other surface forms, so that the fold structure is widely applied to structural design for improving the linearity of the sensor. For example, cheng et al self-assembled a graphene film on the surface of a polymer PDMS and deposited a conductive gold layer, which by pre-stretching the sensor can create net cracks in the gold layer on the surface of the folds, can increase the linearity of the sensor to 0.9975[ ChengX, et al ACSAppl. Mater. Interface 2022,14,34,39230-39239]. Obviously, the layered structure of different conductive materials is also a design strategy that effectively improves linearity while the pleated structure is functioning. The common method for preparing the folds is a stress pre-stretching method, such as the preparation method in the patent with the patent number of CN115096173A, which is difficult to ensure the consistency of the fold structure on different samples, namely the reproducibility is difficult to ensure. Therefore, how to prepare a multistage structure of wrinkles and cracks on a flexible substrate, and achieve high sensitivity and high linearity synergy of a flexible sensor remains a significant challenge.
It should be noted that the foregoing description of the background art is only for the purpose of facilitating a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background section of the present application.
Disclosure of Invention
In view of the defects existing at present, the invention provides the bionic flexible strain sensor with high sensitivity and high linearity and the manufacturing method thereof.
In order to achieve the above purpose, the invention provides a high-sensitivity and high-linearity collaborative bionic flexible strain sensor, which comprises a flexible substrate, a conductive functional layer and an electrode from bottom to top in sequence; a fold structure is distributed on one surface of the flexible matrix near the conductive functional layer; the conductive functional layer is formed by stacking a plurality of layers of different materials.
According to one aspect of the invention, the corrugated structure is prepared by template method, nanoimprint, lithography, laser processing or 3D printing.
According to one aspect of the invention, the width and depth of the cells of the pleated structure are each less than 1000 μm.
According to one aspect of the invention, the material of the conductive functional layer comprises one or more of pure conductive metal micro-nano particles, carbon-based conductive materials and high-molecular polymer materials.
According to one aspect of the invention, the conductive functional layer is made by spray coating, sputter deposition, self-growth, transfer printing, printing or 3D printing.
According to one aspect of the invention, the material of the flexible matrix comprises any one of polydimethylsiloxane, organo platinum silica, thermoplastic elastomer, polyurethane and hydrogel system material.
According to one aspect of the invention, the electrode is electrically attached to the surface of the conductive functional layer.
Based on the same inventive concept, the invention also provides a preparation method of the high-sensitivity and high-linearity collaborative bionic flexible strain sensor, which comprises the following steps:
step 1: spraying a solution containing the bottom layer material of the conductive functional layer on the fold template, and drying to obtain the fold template attached with the bottom layer material of the conductive functional layer;
step 2: uniformly coating the liquid material of the flexible matrix subjected to the defoaming treatment on the bottom layer material of the conductive functional layer on the corrugated template, and obtaining a film of the flexible matrix plus the bottom layer material of the conductive functional layer with a target size through solidification, stripping and cutting;
step 3: the film is placed in a particle sputtering instrument, and the next layer or multiple layers of materials of the conductive functional layer are sputtered on the surface of the bottom layer material of the conductive functional layer, so that the film of the flexible matrix and the conductive functional layer is obtained;
according to one aspect of the invention, the preparation method further comprises:
step 4: and fixing the metal electrodes at two ends of the conductive functional layer by adopting a conductive adhesive tape, and coating conductive silver paste at the joint of the conductive adhesive tape and the conductive functional layer to complete the connection of the circuit.
According to one aspect of the invention, in step 1, the spraying is performed using a spraying device having a nozzle diameter of 1mm, a distance between the nozzle and the surface of the corrugated template of 20cm, and the number of spraying is 4, and the interval time between each spraying is 10s.
The principle of the bionic flexible strain sensor is as follows: when the bionic flexible sensor is subjected to external stress or strain, the size and shape of the surface fold structure of the sensor are changed, and micro-cracks can be generated by micro-deformation, so that the electrical property of the sensor is changed. The combination of microcracks and pleated structures provides high sensitivity and high linearity characteristics for biomimetic sensors with large strain stretching capabilities.
The invention has the beneficial effects that:
(1) The bionic flexible strain sensor can realize high-sensitivity and high-linearity synergy in terms of performance, and can be coupled with high-tensile characteristics according to the inherent properties of the polymer elastic material.
(2) Structurally, the bionic flexible strain sensor combines a fold structure capable of improving linearity and stretchability and a crack structure capable of improving sensitivity. The fold structure is prepared by a template method, the template can be reused, and the fold structure can be prepared repeatedly and uniformly.
(3) From the material aspect, the bionic flexible strain sensor mainly comprises a double-layer conductive layer stack and an elastic material layer. Multiple layers of conductive material can improve the conductive properties of the sensor while still allowing conductive paths to remain under large strains due to the different modulus of elasticity between the different conductive materials.
(4) The sensitivity of the bionic flexible strain sensor is 22.98 in the strain range of 0% -30%. When the strain of the sensor is in the range of 10% strain, the highest linear fitting degree can reach 0.9978, and when the strain of the sensor is respectively in the ranges of 20% and 30%, the linear fitting degree can be improved to 0.9985, which shows that the bionic flexible strain sensor has the characteristics of high sensitivity, high linearity and large strain.
Drawings
FIG. 1 is a schematic diagram illustrating the structure of a high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to embodiment 1 of the present invention;
FIG. 2 is a photomicrograph of the topography of the creped paper used in example 1 of the present invention;
FIG. 3a is an electron microscope image of the surface morphology of the bionic flexible strain sensor according to embodiment 1 of the present invention; FIG. 3b is an enlarged view of part of (1) of FIG. 3 a; FIG. 3c is an enlarged view of part of (2) of FIG. 3 a; FIG. 3d is an enlarged view of a portion of (3) of FIG. 3 a; FIG. 3e is an enlarged view of part of (4) of FIG. 3 a;
FIG. 4a is an electron microscope image of a microcrack structure formed by the bionic flexible strain sensor according to example 1 of the present invention under a tensile strain of 10%; FIG. 4b is an electron microscope image of a microcrack structure formed by the bionic flexible strain sensor according to example 1 of the present invention under 20% tensile strain; FIG. 4c is an electron microscope image of a microcrack structure formed by the bionic flexible strain sensor according to example 1 of the present invention under 30% tensile strain;
FIG. 5 is a cross-sectional morphology electron microscope of the bionic flexible sensor according to embodiment 1 of the present invention;
FIG. 6a is a graph showing the sensitivity, linearity and tensile strain capacity performance test at 10% tensile strain of the bionic flexible sensor according to example 1 of the present invention; FIG. 6b is a graph showing the performance test of sensitivity, linearity and tensile strain amount of the bionic flexible sensor according to example 1 of the present invention under 20% tensile strain; fig. 6c is a chart showing sensitivity, linearity and tensile strain capacity performance test of the bionic flexible sensor according to example 1 of the present invention under 30% tensile strain.
Description of the drawings: 1. a flexible substrate PDMS; 2. a pleated structure; 3. a carbon nanotube layer; 4. an Ag layer; 5. a copper electrode; 6. and (5) conducting wires.
Detailed Description
In order that the invention may be more readily understood, the invention will be further described with reference to the following examples. It should be understood that these examples are intended to illustrate the invention and not to limit the scope of the invention, and that the described embodiments are merely some, but not all, of the embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. Unless defined otherwise, the terms of art used hereinafter are consistent with the meanings understood by those skilled in the art; unless otherwise indicated, all the materials and reagents referred to herein are commercially available or may be prepared by well-known methods.
The creped paper of the present application was purchased from Boshan crepe world paper company.
Currently, flexible strain sensor layers based on various sensing structures, conductive materials, are endless, but achieving a balance between high sensitivity, linearity, and stretchability remains very challenging. Taking a resistive flexible strain sensor as an example, a flexible sensor with large stretchability (i.e., a wide working range) generally has low sensitivity, while a flexible strain sensor with high sensitivity has a small working range. In addition, due to the participation of high molecular polymers in the flexible strain sensor, the working principle of the resistance sensor is generally based on seepage theory, tunneling theory and the like, so that the signal output of the sensor usually appears in a parabolic curve-like form, the linearization is poor, and the resistance sensor can only be fitted in a piecewise manner. With the rise of the nanometer conductive material film, the performance of the sensor can be obviously improved by utilizing the surface microstructure of the conductive film, particularly, the sensor is represented by a crack structure, and the aim of greatly improving the sensitivity is fulfilled by a conductive mechanism of breaking a conductive path under a tiny strain. However, the crack structure brings high sensitivity while also presenting challenges for the stretching range. The fold structure has unique natural advantages, such as large stretchability, large specific surface area, anisotropy and other surface forms, so that the fold structure is widely applied to structural design for improving the linearity of the sensor. Obviously, the layered structure of different conductive materials is also a design strategy that effectively improves linearity while the pleated structure is functioning. A common method for preparing the folds is a stress pre-stretching method, but it is difficult to ensure the consistency of the fold structure on different samples, i.e. the reproducibility is difficult to be ensured. Therefore, how to prepare a multistage structure of wrinkles and cracks on a flexible substrate, and achieve high sensitivity and high linearity synergy of a flexible sensor remains a significant challenge.
In order to solve the problems, the invention provides a high-sensitivity and high-linearity collaborative bionic flexible strain sensor, which sequentially comprises a flexible substrate, a conductive functional layer and an electrode from bottom to top; a fold structure is distributed on one surface of the flexible matrix near the conductive functional layer; the conductive functional layer is formed by stacking a plurality of layers of different materials.
The conductive functional layer is formed by stacking a plurality of layers of different materials, namely, the conductive functional layer is formed by stacking a plurality of conductive layers, and the number of the conductive layers is more than or equal to 2.
Preferably, the fold structure is prepared by a template method, nanoimprint, lithography, laser processing or 3D printing.
Preferably, the width and depth of the cells of the pleated structure are each less than 1000 μm.
Preferably, the material of the conductive functional layer comprises one or more of pure conductive metal micro-nano particles, carbon conductive materials and high polymer materials.
Preferably, the carbon-based conductive material is a carbon nanotube.
Preferably, the conductive functional layer is made by spray coating, sputter deposition, self-growth, transfer printing, printing or 3D printing.
The flexible matrix is an elastic polymer material with good selective stretching property and recovery property
Preferably, the material of the flexible substrate includes any one of Polydimethylsiloxane (PDMS), organo platinum silica gel (Ecoflex), thermoplastic elastomer (styrene-butadiene-styrene block copolymer SBS, styrene-ethylene-butylene-styrene block copolymer SEBS, thermoplastic polyurethane elastomer TPU, polyester elastomer TPEE, etc.), polyurethane PU, hydrogel system material.
Preferably, the electrode is electrically attached to the surface of the conductive functional layer.
The invention also provides a preparation method of the high-sensitivity and high-linearity collaborative bionic flexible strain sensor, which comprises the following steps:
step 1: spraying a solution containing the bottom layer material of the conductive functional layer on the fold template, and drying to obtain the fold template attached with the bottom layer material of the conductive functional layer;
preferably, in step 1, the spraying is performed by a spraying device, the diameter of a nozzle of the spraying device is 1mm, the distance between the nozzle and the surface of the corrugated template is 20cm, the spraying times are 4 times, and the interval time between each spraying is 10s.
Illustratively, the corrugated template is a corrugated paper purchased directly or a template prepared by nanoimprinting, photolithography, laser machining or 3D printing.
Preferably, the pleated template is a directly purchased pleated paper.
Step 2: uniformly coating the liquid material of the flexible matrix subjected to the defoaming treatment on the bottom layer material of the conductive functional layer on the corrugated template, and obtaining a film of the flexible matrix plus the bottom layer material of the conductive functional layer with a target size through solidification, stripping and cutting;
preferably, the defoaming treatment specifically includes: and (3) placing the liquid material of the flexible matrix which is uniformly mixed according to the proportion into a vacuum pump for degassing treatment for 30 min.
Preferably, the curing is specifically an oven curing at 80℃for 2 hours.
Step 3: the film is placed in a particle sputtering instrument, and the next layer or multiple layers of materials of the conductive functional layer are sputtered on the surface of the bottom layer material of the conductive functional layer, so that the film of the flexible matrix and the conductive functional layer is obtained;
preferably, the preparation method further comprises:
step 4: and fixing the metal electrodes at two ends of the conductive functional layer by adopting a conductive adhesive tape, and coating conductive silver paste at the joint of the conductive adhesive tape and the conductive functional layer to complete the connection of the circuit.
Further details are provided below in connection with specific examples.
Example 1
1) Firstly preparing a solution, adding 0.5g of carbon nano tube into 10ml of absolute ethyl alcohol, magnetically stirring for 20min at room temperature, and then performing ultrasonic vibration for 1 hour to fully dissolve the carbon nano tube in the solutionAbsolute ethyl alcohol; the prepared solution was then sprayed onto creped paper (Boshan crepe paper company, bobo Co., ltd., 25 g/M) by means of a spraying device 2 Crepe rate: 25% or more) of the surface, the diameter of the nozzle of the spraying device is 1mm, the distance between the nozzle and the surface of the corrugated paper is 20cm, the spraying times are 4 times, and the time interval of each spraying is 10s. Finally, placing the sample on a heating table at 60 ℃ for heating and drying for 10 minutes;
2) Uniformly mixing a curing agent of the polymer PDMS and a precursor according to the weight ratio of 1:10, and placing the mixture in a vacuum pump for degassing treatment for 30 minutes;
3) Uniformly coating the degassed PDMS liquid on the surface of the corrugated paper with the carbon nanotube powder by using a tape casting method, and then placing a sample into an oven for curing treatment at 80 ℃ for 2 hours;
4) After curing, peeling off the PDMS film, observing that the surface of the film has a uniform fold structure through a microscope, and selecting a proper area for cutting, wherein the size of the area is 30mm multiplied by 10mm (l multiplied by w);
5) Putting the PDMS film into a particle sputtering instrument, and sputtering a 150nm silver particle layer on the surface of the PDMS film to serve as a conductive material;
6) And (3) fixing metal electrodes at two ends of the PDMS film with the film thickness by adopting a conductive adhesive tape, coating conductive silver paste at the joint of the conductive adhesive tape and the silver layer to complete connection of a circuit, thereby obtaining the sensor with the structure shown in figure 1, and carrying out morphology and performance characterization on the sensing element.
Performance inspection and result analysis:
fig. 1 shows a high-sensitivity and high-linearity collaborative bionic flexible strain sensor of embodiment 1, which comprises a flexible substrate PDMS1 with a corrugated structure 2 on the surface, a carbon nanotube layer 3 and an Ag layer 4 on the surface from bottom to top, and finally a copper electrode 5 and a wire 6. The preparation flow of the sensor comprises a corrugated paper template for structure transfer, a dispersion liquid configuration of carbon nano tubes in absolute ethyl alcohol, spraying of the carbon nano tube dispersion liquid on the corrugated paper, preparation of a PDMS film and sputtering of silver nano particles. The surface topography of the pleated paper used is shown in fig. 2. The surface morphology of the prepared bionic flexible sensor is shown in figure 3. Fig. 4 is a morphology electron microscope image of microcracks of the bionic sensor of example 1 under different tensile strains (10%, 20%, 30%), and it can be seen that the microcrack spacing increases slowly with increasing strain, and no straight crack is generated. The crack structures are distributed at the pits of the fold structure in a substantially parallel staggered manner under different strains. Under 30% strain, the crack width is about 2 mu m, and the existence of the carbon nano tube can be seen at the gap of the silver layer, so that the gap of the silver layer crack is filled, and the effect of maintaining the electrical property of the sensing element is achieved. FIG. 5 is a cross-sectional morphology electron microscope image of the bionic flexible sensor of the invention, showing that the thickness of the sensor is about 1.5mm, the maximum thickness of the carbon nano tube is about 600 μm, and the thickness of the silver layer is about 150nm. The results of the bionic flexible sensor sensitivity, linearity and tensile strain capacity performance test are shown in fig. 6. The sensitivity of the bionic sensor in the strain range of 0% -30% is 22.98. When the strain of the sensor is in the range of 10% strain, the highest linear fitting degree can reach 0.9978, and when the strain of the sensor is respectively in the ranges of 20% and 30%, the linear fitting degree can be improved to 0.9985, which shows that the sensor has the characteristics of high sensitivity, high linearity and large strain.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A bionic flexible strain sensor with high sensitivity and high linearity is characterized in that the strain sensor sequentially comprises a flexible substrate, a conductive functional layer and an electrode from bottom to top; a fold structure is distributed on one surface of the flexible matrix near the conductive functional layer; the conductive functional layer is formed by stacking a plurality of layers of different materials.
2. The high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 1, wherein the pleated structure is fabricated by template method, nanoimprint, lithography, laser processing, or 3D printing.
3. The high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 1, wherein the width and depth of the cells of the pleated structure are each below 1000 μm.
4. The high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 1, wherein the material of the conductive functional layer comprises one or more of pure conductive metal micro-nano particles, carbon conductive materials and high-molecular polymer materials.
5. The high sensitivity and high linearity collaborative bionic flexible strain sensor according to claim 1, wherein the conductive functional layer is made by spray coating, sputter deposition, self-growth, transfer printing, printing or 3D printing.
6. The high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 1, wherein the flexible substrate material comprises any one of polydimethylsiloxane, organo platinum silica gel, thermoplastic elastomer, polyurethane, hydrogel system material.
7. The high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 1, wherein the electrode is electrically attached to the surface of the conductive functional layer.
8. A method for preparing the high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to any one of claims 1-7, comprising the following steps:
step 1: spraying a solution containing the bottom layer material of the conductive functional layer on the fold template, and drying to obtain the fold template attached with the bottom layer material of the conductive functional layer;
step 2: uniformly coating the liquid material of the flexible matrix subjected to the defoaming treatment on the bottom layer material of the conductive functional layer on the corrugated template, and obtaining a film of the flexible matrix plus the bottom layer material of the conductive functional layer with a target size through solidification, stripping and cutting;
step 3: and (3) placing the film in a particle sputtering instrument, and sputtering the next layer or layers of materials of the conductive functional layer on the surface of the bottom layer material of the conductive functional layer to obtain the film of the flexible matrix and the conductive functional layer.
9. The method for preparing the high-sensitivity and high-linearity collaborative bionic flexible strain sensor according to claim 8, wherein the method for preparing further comprises:
step 4: and fixing the metal electrodes at two ends of the conductive functional layer by adopting a conductive adhesive tape, and coating conductive silver paste at the joint of the conductive adhesive tape and the conductive functional layer to complete the connection of the circuit.
10. The method for preparing the bionic flexible strain sensor with high sensitivity and high linearity according to claim 8, wherein in step 1, the spraying is completed by a spraying device, the diameter of a nozzle of the spraying device is 1mm, the distance between the nozzle and the surface of the corrugated template is 20cm, the spraying times are 4 times, and the interval time between each spraying is 10s.
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| CN117537699B (en) * | 2024-01-09 | 2024-04-12 | 西南交通大学 | Flexible strain sensor and preparation method thereof |
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