阅读说明：本技术 一种基于丙烯酰胺/氧化碳纳米管纳米复合水凝胶传感器及其制备方法 (acrylamide/carbon oxide nanotube-based nanocomposite hydrogel sensor and preparation method thereof ) 是由 姚芳莲 孙侠 李俊杰 秦志辉 于 2019-08-08 设计创作，主要内容包括：本发明涉及一种基于丙烯酰胺/氧化碳纳米管纳米复合水凝胶传感器及其制备方法；配置明胶水溶液,加入氧化碳纳米管,得到分层的氧化碳纳米管浊液；用超声波处理,得到分散氧化碳纳米管分散液；称取丙烯酰胺加入碳纳米管分散液中,并加入引发剂过硫酸铵,交联剂为N’,N’-二甲基双丙烯酰胺,在氩气保护下,磁力搅拌溶液；将溶液转移至片状模具中,进行自由基聚合,得到片状纳米复合水凝胶；将所得水凝胶用VHB胶带封装,两端加上铜电极和导线,得到高强度可拉伸的应变传感器。应变传感器的反应时间为0.3s,并且在300次反复拉伸后仍然可以保持稳定可重复的信号输出；有着优异的敏感性,并且在检测人体运动方面得到了实际应用。(The invention relates to a sensor based on acrylamide/carbon oxide nanotube nano composite hydrogel and a preparation method thereof; preparing a gelatin aqueous solution, and adding the carbon oxide nanotube to obtain a layered carbon oxide nanotube turbid solution; treating with ultrasonic wave to obtain dispersed carbon oxide nanotube dispersion liquid; weighing acrylamide, adding the acrylamide into the carbon nano tube dispersion liquid, adding an initiator ammonium persulfate, wherein a cross-linking agent is N ', N' -dimethyl bisacrylamide, and magnetically stirring the solution under the protection of argon; transferring the solution into a sheet-shaped mold, and carrying out free radical polymerization to obtain sheet-shaped nano composite hydrogel; and packaging the obtained hydrogel by using a VHB adhesive tape, and adding copper electrodes and leads at two ends to obtain the high-strength stretchable strain sensor. The response time of the strain sensor is 0.3s, and the stable and repeatable signal output can be still kept after 300 times of repeated stretching; has excellent sensitivity and is practically applied to the detection of human body movement.)

1. The sensor is characterized in that the strain sensor takes carbon nanotubes dispersed by gelatin as a conductive material, polyacrylamide as a substrate and water as a medium, and comprises the following components in percentage by weight: 3-4.4 wt% of gelatin, 0.15-1.5 wt% of carbon oxide nanotube, 10-25 wt% of acrylamide and the balance of water.

2. A preparation method of a sensor based on acrylamide/oxidized carbon nanotube nano composite hydrogel comprises the following steps:

(1) Preparing a gelatin water solution with the mass fraction of 4-6 wt%, and adding the carbon oxide nanotube into the gelatin water solution to obtain layered carbon oxide nanotube turbid liquid; treating the obtained turbid solution with 100-300 frequency ultrasonic waves to obtain uniformly dispersed oxidized carbon nanotube dispersion liquid;

(2) Weighing acrylamide, adding the acrylamide into the carbon nano tube dispersion liquid obtained in the step (1), adding an initiator ammonium persulfate, wherein a cross-linking agent is N ', N' -dimethyl bisacrylamide, and magnetically stirring the mixture to obtain a uniform solution under the protection of argon;

(3) Transferring the solution stirred by the magnetic force in the step (2) into a sheet-shaped die, and carrying out free radical polymerization at 40-60 ℃ to obtain sheet-shaped nano composite hydrogel;

(4) And packaging the obtained hydrogel by using a VHB adhesive tape, and adding copper electrodes and leads at two ends to obtain the high-strength stretchable strain sensor.

3. the method as set forth in claim 2, wherein the ultrasonic treatment time in the step (1) is 30min to 2 h.

4. The method as set forth in claim 2, wherein the ultrasonic frequency in the step (1) is 150 and 250 Hz.

5. The method as set forth in claim 2, wherein the acrylamide content in said step (2) is 10.9-21.8 wt% based on the total mass of the gel.

6. The method as set forth in claim 2, characterized in that the initiator ammonium persulfate content in the step (2) is 0.1 mol% based on the acrylamide monomer.

7. the method as set forth in claim 2, characterized in that the crosslinking agent in the step (2) is N ', N' -dimethylbisacrylamide in an amount of 0.03 mol% based on the acrylamide monomer.

8. The method as set forth in claim 2, wherein the magnetic stirring in the step (2) is carried out for 30 to 60 min.

9. the method as set forth in claim 2, wherein the radical polymerization time in said step (3) is 3 to 6 hours.

Technical Field

The invention relates to a sensor based on acrylamide/carbon oxide nanotube nano composite hydrogel and a preparation method thereof; belongs to the field of functional materials.

Background

Recently, stretchable, wearable electronics have found wide application in electronic skin, artificial intelligence, energy storage devices, and human motion monitoring. Among them, strain sensors similar to skin have attracted researchers' attention because they can convert mechanical signals such as tension, bending, etc. into corresponding electrical signals such as resistance, current, etc. In order to satisfy various applications, these deformation sensors should have characteristics of high strength, stretchability, simplicity of fabrication, and the like. However, in the conventional strain sensor, conductive polymer, metal, graphene or the like is doped in a composite substrate, and although the conventional strain sensor has good sensitivity, the conventional strain sensor is generally rigid and has a low elongation (< 200%), so that the conventional strain sensor is difficult to be applied in practice. Therefore, the design of a novel high-strength stretchable strain sensor has important application value.

Hydrogel-based strain sensors have been a new focus of research since their good stretchability, biocompatibility and similarity to human tissue. The hydrogel can be endowed with conductive performance by in-situ polymerization of conductive polymers or doping of conductive nanoparticles such as carbon nanotubes and the like in the hydrogel, so that the hydrogel can be applied to a strain sensor. However, these hydrogel-based strain sensors are severely limited in their practical application due to the non-uniformity of the doped particles, generally poor mechanical properties or low elongation. In addition, hydrogel-based sensors often lack self-healing properties and are not conducive to long-term reuse. Meanwhile, the preparation process of the gel is complicated and the components are complex. Therefore, the preparation of conductive hydrogel which is stretchable with high strength and has good self-recovery property and the application of the conductive hydrogel in a sensor still remain to be solved.

Disclosure of Invention

The invention aims to overcome the defects of poor strength, low tensile rate and the like of the conventional hydrogel strain sensor by uniformly dispersing the carbon oxide nanotubes, and provides a strain sensor which has high strength and is stretchable and can be practically applied and a manufacturing method thereof.

The technical scheme of the invention is as follows:

An acrylamide/carbon oxide nanotube-based nano composite hydrogel and a preparation method thereof are disclosed: combining an oxidized multi-walled carbon nanotube with conductive performance with a polyacrylamide base with excellent tensile performance; oxidizing the multi-wall carbon nano-tube by concentrated nitric acid to obtain an oxidized carbon nano-tube with the surface rich in carboxyl; the carbon oxide nano tube can be combined with gelatin through hydrogen bond action to obtain good water solubility; adding an acrylamide monomer into the carbon oxide nanotube dispersion liquid, and carrying out free radical polymerization under the action of a cross-linking agent and an initiator; due to the nanometer reinforcing effect of the carbon oxide nanotube and a large amount of hydrogen bond effects contained in a gel system, the nanometer composite hydrogel is reinforced, and the high-strength conductive hydrogel is obtained;

An acrylamide/carbon nanotube oxide based nanocomposite hydrogel sensor: the composite hydrogel was coated with VHB tape from 3M company to obtain a high-strength stretchable strain sensor.

the invention relates to an acrylamide/oxidized carbon nanotube-based nanocomposite hydrogel sensor, which takes gelatin-dispersed carbon nanotubes as a conductive material, polyacrylamide as a substrate and water as a medium, and comprises the following components in percentage by weight: 3-4.4 wt% of gelatin, 0.15-1.5 wt% of carbon oxide nanotube, 10-25 wt% of acrylamide and the balance of water.

The invention discloses a preparation method of a sensor based on acrylamide/oxidized carbon nanotube nano composite hydrogel, which comprises the following steps:

(1) Preparing a gelatin water solution with the mass fraction of 4-6 wt%, and adding the carbon oxide nanotube into the gelatin water solution to obtain layered carbon oxide nanotube turbid liquid; treating the obtained turbid solution with 100-300 frequency ultrasonic waves to obtain uniformly dispersed oxidized carbon nanotube dispersion liquid;

(2) Weighing acrylamide, adding the acrylamide into the carbon nano tube dispersion liquid obtained in the step (1), adding an initiator ammonium persulfate, wherein a cross-linking agent is N ', N' -dimethyl bisacrylamide, and magnetically stirring the mixture to obtain a uniform solution under the protection of argon;

(3) transferring the solution stirred by the magnetic force in the step (2) into a sheet-shaped die, and carrying out free radical polymerization at 40-60 ℃ to obtain sheet-shaped nano composite hydrogel;

(4) And packaging the obtained hydrogel by using a VHB adhesive tape, and adding copper electrodes and leads at two ends to obtain the high-strength stretchable strain sensor.

preferred conditions are as follows:

The ultrasonic treatment time in the step (1) is 30min-2 h.

The ultrasonic frequency in the step (1) is 150-250 Hz.

In the step (2), the content of acrylamide accounts for 10.9-21.8 wt% of the total mass of the gel.

in the step (2), the content of the initiator ammonium persulfate is 0.1 mol% of the acrylamide monomer.

In the step (2), the content of the crosslinking agent N ', N' -dimethyl bisacrylamide is 0.03 mol% of the acrylamide monomer.

And (3) magnetically stirring for 30-60min in the step (2).

The free radical polymerization time in the step (3) is 3-6 h.

compared with the prior art, the invention has the following beneficial effects: the gelatin is adopted to disperse the carbon oxide nanotubes, the operation is simple, and the carbon oxide nanotubes are dispersed uniformly. Acrylamide is used as a main material of the hydrogel, and raw materials are easy to obtain. The prepared nano composite hydrogel has good strength, stretchability and self-recovery property, and the strain sensor prepared from the nano composite hydrogel has good sensitivity, quick reaction time and wider detection range. The strength of the hydrogel can reach 0.71MPa at most, and the elongation is 1070 percent. The response time of the strain sensor is 0.3s, and the stable and repeatable signal output can still be maintained after 300 times of repeated stretching. In addition, the strain sensor has excellent sensitivity and is practically used for detecting human body movement.

drawings

FIG. 1: the nano composite hydrogel bears optical photos of different deformations;

FIG. 2: the tensile mechanical properties of the nanocomposite hydrogel;

FIG. 3: self-recovery properties of the nanocomposite hydrogel;

FIG. 4: high strength tensile strain sensors detect bending movements at different parts of the human body.

the specific implementation mode is as follows:

the technical scheme of the invention is further explained by combining specific examples. The reagents used in the following examples include essentially the following: gelatin, oxidized carbon nanotubes, acrylamide and deionized water.