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CN-122016101-A - Double-sensitive-layer flexible piezoresistive sensor

CN122016101ACN 122016101 ACN122016101 ACN 122016101ACN-122016101-A

Abstract

The invention discloses a double-sensitive-layer flexible piezoresistive sensor which sequentially comprises an upper electrode layer, an upper sensitive layer, a lower sensitive layer and a lower electrode layer from top to bottom, wherein the upper sensitive layer and the lower sensitive layer are mainly made of composite materials made of MWCNTs and SR, the surface of the upper sensitive layer facing the lower sensitive layer is provided with a sand paper-like microstructure, and the surface of the lower sensitive layer facing the upper sensitive layer is provided with a plurality of inclined convex microstructures. The inclined bulge microstructure of the lower sensitive layer is configured into a quadrangular pyramid, the inclination angle of the quadrangular pyramid is 70-130 degrees, and the inclination angle is an included angle between the bottom edge and the side edge of the triangular section which is formed by passing through the top point of the quadrangular pyramid and is perpendicular to one bottom edge of the bottom surface. The invention can simultaneously give consideration to high sensitivity and wide range, realizes sensitive detection when the piezoresistive sensor is subjected to inclined stress, and finally realizes remarkable improvement of the comprehensive performance of the sensor.

Inventors

  • HE XINRAN
  • WANG ZHITONG

Assignees

  • 安徽大学

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. A flexible piezoresistive sensor with double sensitive layers is characterized by comprising an upper electrode layer, an upper sensitive layer, a lower sensitive layer and a lower electrode layer from top to bottom in sequence, wherein the upper sensitive layer and the lower sensitive layer are mainly made of composite materials made of MWCNTs and SR, the surface of the upper sensitive layer facing the lower sensitive layer is provided with a sand paper-like microstructure, the surface of the lower sensitive layer facing the upper sensitive layer is provided with a plurality of inclined bulge microstructures, the inclined bulge microstructures of the lower sensitive layer are configured into quadrangular cones, the inclination angle of each quadrangular cone is 70-130 degrees, and the inclination angle is an included angle between the bottom edge and the side edge of each triangular section in a triangular section formed by passing through the top point of each quadrangular cone and being perpendicular to one bottom edge of the bottom surface.
  2. 2. The flexible piezoresistive sensor according to claim 1, wherein an SR substrate is further arranged between the upper sensitive layer and the lower sensitive layer, and an intermediate electrode layer is arranged on the outer half-surrounding of the SR substrate.
  3. 3. The dual sensitive layer flexible piezoresistive sensor according to claim 1, characterized in that the outer surface of the upper electrode layer and/or the lower electrode layer is coated with an SR layer.
  4. 4. The dual sensitive layer flexible piezoresistive sensor according to claim 1, characterized in that the tilt directions of the plurality of tilt-bump microstructures are the same or different.
  5. 5. The dual sensitive layer flexible piezoresistive sensor according to claim 4, characterized in that the inclination of the quadrangular pyramid is 90 °.
  6. 6. The flexible piezoresistive sensor according to claim 4, wherein the bottom surface of the pyramid is a parallelogram, wherein the length of one side is 2.5 to 3.5mm, the length of the other side is 2 to 4mm, and the height of the pyramid is 3 to 5mm.
  7. 7. The flexible piezoresistive sensor according to claim 6, wherein the bottom surface of the quadrangular pyramid is diamond with a side length of 3mm and a height of 4mm.
  8. 8. The flexible piezoresistive sensor according to claim 2, wherein the sandpaper-like microstructure of the upper sensitive layer is obtained by transferring a sandpaper template, the mesh number of the sandpaper template being 80-150 mesh.
  9. 9. The dual sensitive layer flexible piezoresistive sensor according to claim 8, characterized in that the mesh number of the sandpaper template is 120 mesh.
  10. 10. The flexible piezoresistive sensor according to claim 1, characterized in that the MWCNTs/SR composite solution used for the preparation of the upper and lower sensitive layers has a doping concentration of 4%.

Description

Double-sensitive-layer flexible piezoresistive sensor Technical Field The invention relates to the technical field of flexible pressure sensors, in particular to a double-sensitive-layer flexible piezoresistive sensor. Background Flexible pressure sensors can be classified into four types according to their operating mechanisms, namely, capacitive type, piezoelectric type, piezoresistive type and triboelectric type, wherein piezoresistive type sensors are important for research because of their simple manufacturing process, low power consumption and excellent stability. The reasonable selection of the active material of the piezoresistive sensor is an important factor for realizing high performance, and the performance of the piezoresistive sensor can be obviously improved by optimizing the selection of the material, but the piezoresistive sensor has the problems of high preparation cost, easy falling of the conductive material in long-term use and the like. Besides reasonable selection on the conductive material, the design optimization of the surface microstructure can be used for distributing mechanical stress, so that the overall responsiveness of the piezoresistive sensor is improved. However, due to factors such as insufficient viscoelasticity of sensitive materials and structures, insufficient contact interface change and the like, obvious hysteresis may occur in the loading/unloading process of the sensor, and measurement accuracy and repeatability are affected. Moreover, the existing flexible piezoresistive sensor is difficult to achieve both high sensitivity and wide range, so that effective resolution and stable output are difficult to maintain in a wider pressure range. Meanwhile, the problem of performance limitation caused by underutilization of microstructure contact sites possibly exists in the sensor with the multilayer structure, and the change amplitude of contact resistance and effective signal output are weakened. In addition, piezoresistive sensors are often used for flexible sensing on a manipulator, and the force applied by the piezoresistive sensor is often not in a positive vertical direction, but at an oblique angle. Based on force decomposition, the pressure of the inclined angle can be decomposed into two component forces perpendicular to the surface of the piezoresistive sensor and parallel to the surface of the piezoresistive sensor, but the flexible piezoresistive sensor in the prior art is designed by only considering the sensitivity condition under the condition of forward vertical force, and neglecting the influence of the horizontal component force on the piezoresistive sensor. Disclosure of Invention The invention relates to the term: MWCNTs, multiwall carbon nanotubes. SR, silicone rubber. MLP Multilayer Perceptron, representing a multi-layer perceptron. In order to solve the technical problems in the background technology, the invention provides a double-sensitive-layer flexible piezoresistive sensor which can effectively detect pressure signals in a wider pressure range and has higher sensitivity. The invention provides a double-sensitive-layer flexible piezoresistive sensor which sequentially comprises an upper electrode layer, an upper sensitive layer, a lower sensitive layer and a lower electrode layer from top to bottom, wherein the upper sensitive layer and the lower sensitive layer are mainly made of composite materials made of MWCNTs and SR, the surface of the upper sensitive layer facing the lower sensitive layer is provided with a sand paper-like microstructure, the surface of the lower sensitive layer facing the upper sensitive layer is provided with a plurality of inclined bulge microstructures, the inclined bulge microstructures of the lower sensitive layer are configured into quadrangular cones, the inclination angle of each quadrangular cone is 70-130 degrees, and the inclination angle is an included angle between the bottom edge and the side edge of each triangular section in a triangular section formed by passing through the top point of each quadrangular cone and being perpendicular to one bottom edge of the bottom surface. Further, an SR substrate is arranged between the upper sensitive layer and the lower sensitive layer, and an intermediate electrode layer is arranged on the outer side of the SR substrate in a semi-surrounding manner. Further, the outer surface of the upper electrode layer and/or the lower electrode layer is coated with an SR layer. Further, the oblique directions of the plurality of oblique convex microstructures are the same or different. Further, the inclination angle of the quadrangular pyramid is 90 °. Further, the bottom surface of the quadrangular pyramid is a parallelogram, wherein the length of one side is 2.5-3.5 mm, the length of the other side is 2-4 mm, and the height of the quadrangular pyramid is 3-5 mm. Further, the bottom surface of the quadrangular pyramid is a diamond with the side length of 3mm and the height of