Preparation method of hydrogel flexible strain sensor with resistance-capacitance dual modes and sensor

A strain sensor, hydrogel technology, applied in chemical instruments and methods, electrical/magnetic solid deformation measurement, electromagnetic measurement devices, etc., can solve problems such as sensor failure, inability to meet stress, and shorten sensor life

Active Publication Date: 2021-12-14
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The currently reported hydrogel flexible strain sensors all use rigid materials such as metal sheets and copper wires as electrodes, which cannot satisfy the application of a large number of complex and dynamic stresses, and are prone to breakage under the action of external force damage, resulting in sensor failure.
When the flexible sensor is stretched as a whole, since the rigid material electrode cannot deform together with the hydrogel, the interface between the electrode and the hydrogel bears a large stress, which will bring large fluctuations to the measurement of the sensing signal, and the metal electrode ( Such as copper wire) long-term use will react with hydrogel, be corroded, and shorten the service life of the sensor
These issues limit its application in wearable devices
In addition, most of the currently reported hydrogel flexible strain sensors adopt resistive sensing, and the sensing form is single, which cannot meet the requirements of capacitive / resistive dual mode use.

Method used

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  • Preparation method of hydrogel flexible strain sensor with resistance-capacitance dual modes and sensor
  • Preparation method of hydrogel flexible strain sensor with resistance-capacitance dual modes and sensor
  • Preparation method of hydrogel flexible strain sensor with resistance-capacitance dual modes and sensor

Examples

Experimental program
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Effect test

Embodiment 1

[0056] Example 1 Hydrogel Flexible Strain Sensor with Resistance and Capacitance Dual Modes

[0057] The sensor prepared in this embodiment includes the upper glue layer 5, the middle glue layer 3 and the lower glue layer 1 of the same shape; the upper grid electrode 4 is arranged between the upper glue layer 5 and the middle glue layer 3, and the lower glue layer 1 and the middle glue layer The lower grid electrode 2 is arranged between the layers 3; the wide side of the upper grid electrode 4 matches the width of the intermediate adhesive layer 3, and the long side extends to the outside of the long sides on both sides of the intermediate adhesive layer 3; the lower grid electrode 2 The shape is the same as that of the upper grid electrode 4; the outer surface of the sensor is provided with a flexible polymer film encapsulation layer.

[0058] The sensor preparation method is as follows:

[0059] Step (1), dissolve 15.6g of acrylamide monomer and 17.5g of sodium chloride in...

Embodiment 2

[0072] The sensor preparation method of this embodiment is the same as that of Embodiment 1, except that the thickness of the lower rubber layer in this embodiment is 0.5 mm, the thickness of the middle rubber layer is 1 mm, and the thickness of the upper rubber layer is 0.5 mm. The structure of the upper grid electrode and the lower grid electrode is as follows Figure 7 As shown, it is a spring-like connection grid structure, which is made of thermoplastic polyurethane, with a line width of 20 μm and a thickness of 50 μm. The thickness of the metal chromium layer evaporated on the surface is 5 nm, and the thickness of the gold layer is 25 nm.

[0073] In this embodiment, the lengths of the lead electrodes 6-9 (that is, the parts on both sides of the long sides of the upper / lower grid electrodes that exceed the long sides of the intermediate adhesive layer) are all 1 cm.

[0074] Referring to the method of Example 1, the hydrogel flexible strain sensor with resistance-capacit...

Embodiment 3

[0076] The sensor preparation method of this embodiment is the same as that of Embodiment 1, and the difference from Embodiment 1 is that the structure of the upper grid electrode and the lower grid electrode of this embodiment is as follows Figure 8 As shown, it is a spring-like connection grid structure, which is made of thermoplastic polyurethane, with a line width of 500 μm and a thickness of 200 μm. The thickness of the evaporated metal titanium layer on the surface is 20 nm, and the thickness of the gold layer is 100 nm.

[0077] Referring to the method of Example 1, the hydrogel flexible strain sensor with resistance-capacitance dual mode obtained in this example is tested. When the tensile strain is 5%, 10%, and 15%, the resistance changes between wiring 6 and 7 are respectively 17.2%, 19.4%, and 21.6%, and the capacitance changes between wiring 6 and 8 are 7.5%, 15.3%, and 24.6%, which have remarkable resistance-capacitance dual-mode sensing characteristics.

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Abstract

The invention relates to the technical field of hydrogel, and provides a preparation method of a hydrogel flexible strain sensor with resistance-capacitance dual modes and the sensor. The sensor is formed by laminating and compounding hydrogel and a flexible grid electrode, according to different wiring modes, the sensor has a resistive working mode and a capacitive working mode, resistive sensing is achieved through the flexible grid electrode with strain response capacity, capacitive sensing is achieved through a double-electric-layer capacitor at the interface of the hydrogel and the flexible grid electrode, and thesensor can be used for detecting tensile strain; and the whole flexible device designed by the invention has good stretchability, high sensitivity and wide detection range, can realize real-time monitoring of tiny and violent human motion, and can be applied to the fields of wearable equipment, flexible robots, electronic skin and the like.

Description

technical field [0001] The invention relates to the field of hydrogel technology, in particular to a hydrogel flexible strain sensor with resistance-capacitance dual modes. Background technique [0002] With the development of intelligence in modern society, research on flexible smart wearable devices is increasing, and the demand for sensors with strong stretchability and ductility is rapidly increasing. Compared with traditional flexible strain sensors based on metals and semiconductors, hydrogel flexible strain sensors have been extensively studied due to their good stretchability and simple fabrication methods. [0003] Patent CN 112724339A discloses a hydrogel flexible strain sensor and its preparation method, including the following steps: step 1, mixing and dissolving monomer acrylamide, calcium chloride, sodium caseinate, and polydopamine solution in deionized water Obtain a mixed solution; step 2, add a chemical crosslinking agent N,N'-methylenebisacrylamide into t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B27/34B32B27/40B32B27/08B32B3/12B32B33/00C08F220/56C08F222/38G01B7/16
CPCB32B27/34B32B27/40B32B27/08B32B3/12B32B33/00C08F220/56G01B7/18B32B2307/54C08F222/385
Inventor 周建新胡聪周玉成戎家胜
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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