阅读说明：本技术 柔性、可拉伸硅橡胶基可穿戴应变传感纤维的制备方法 (Preparation method of flexible and stretchable silicon rubber-based wearable strain sensing fiber ) 是由 马忠雷 向小莲 魏阿静 马建中 邵亮 康松磊 张梦辉 谌亚茹 于 2019-10-12 设计创作，主要内容包括：柔性、可拉伸硅橡胶基可穿戴应变传感纤维的制备方法,包括以下步骤：采用硅烷偶联剂于氮气氛围保护下对羟基多壁碳纳米管进行表面功能化改性；将硅橡胶注入聚四氟乙烯管并固化制得透明无气泡且表面光滑的硅橡胶纤维；将功能化改性多壁碳纳米管分散于硅橡胶中得到功能化改性多壁碳纳米管的前驱体分散液；通过浸涂法将前驱体分散液包覆于硅橡胶纤维表面并固化制得低填充、柔性、可拉伸且高灵敏的核壳结构硅橡胶基可穿戴应变传感纤维,在电阻可变导体、人工智能和可穿戴设备等领域具有良好的应用前景。(The preparation method of the flexible and stretchable silicon rubber-based wearable strain sensing fiber comprises the following steps: performing surface functional modification on the hydroxyl multi-walled carbon nanotube by adopting a silane coupling agent under the protection of nitrogen atmosphere; injecting silicon rubber into a polytetrafluoroethylene tube and curing to prepare transparent bubble-free silicon rubber fiber with a smooth surface; dispersing the functionalized modified multi-walled carbon nanotubes in silicone rubber to obtain a precursor dispersion liquid of the functionalized modified multi-walled carbon nanotubes; the precursor dispersion liquid is coated on the surface of the silicon rubber fiber by a dip-coating method and is cured to prepare the low-filling, flexible, stretchable and highly sensitive core-shell structure silicon rubber-based wearable strain sensing fiber, and the fiber has good application prospects in the fields of resistance variable conductors, artificial intelligence, wearable equipment and the like.)

1. The preparation method of the flexible and stretchable silicon rubber-based wearable strain sensing fiber is characterized by comprising the following steps of:

step 1, performing reflux reaction on a silane coupling agent in a toluene solvent protected by nitrogen atmosphere at 60-100 ℃ for 12-24 h to modify the surface of a hydroxyl multi-walled carbon nanotube, performing vacuum filtration and washing, and drying in an oven at 60-80 ℃ for 3-8 h to obtain a functionalized modified multi-walled carbon nanotube;

step 2, taking the silicone rubber component A and the silicone rubber component B, magnetically stirring for 10-40 min according to a mass ratio of 8: 1-12: 1 until the components are uniformly mixed, degassing for 10-40 min until a precursor mixed solution is bubble-free, injecting the precursor mixed solution into a polytetrafluoroethylene tube, and curing in an oven at 60-80 ℃ for 1-3 h to prepare the transparent bubble-free silicone rubber fiber with a smooth surface;

step 3, weighing the silicone rubber A component, dissolving the silicone rubber A component in a solvent, adding the functionalized modified multi-walled carbon nanotubes, uniformly dispersing, and then placing the mixture in an oven at the temperature of 60-80 ℃ to remove the solvent; adding the silicone rubber component B according to the mass ratio of the silicone rubber component A to the silicone rubber component B of 8: 1-12: 1, uniformly mixing, and degassing for 10-40 min to obtain a precursor dispersion liquid of the functionalized modified multi-walled carbon nanotube;

step 4, immersing the silicone rubber fiber prepared in the step 2 into the functional modified multi-walled carbon nanotube precursor dispersion liquid prepared in the step 3, so that the functional modified multi-walled carbon nanotube precursor dispersion liquid is coated on the surface of the silicone rubber fiber; and taking out the fiber, and curing the fiber in an oven at the temperature of 60-80 ℃ for 1-3 hours to obtain the flexible and stretchable silicon rubber-based wearable strain sensing fiber with the core-shell structure.

2. The method for preparing the flexible and stretchable silicone rubber-based wearable strain sensing fiber according to claim 1, wherein the silane coupling agent in step 1 is one of KH550, KH560 and KH 570.

3. The preparation method of the flexible and stretchable silicone rubber-based wearable strain sensing fiber according to claim 1, wherein the concentration of the silane coupling agent in the toluene solution in the step 1 is 2-8 g/L.

4. The method of claim 1, wherein the solvent in step 3 is one of tetrahydrofuran, cyclohexane or n-hexanol.

5. The method for preparing the flexible and stretchable silicone rubber-based wearable strain sensing fiber according to claim 1, wherein the functionalized and modified multi-walled carbon nanotubes in the step 3 can be replaced by one of graphene, metal nanowires or metal nanoparticles.

6. The method for preparing the flexible and stretchable silicone rubber-based wearable strain sensing fiber according to claim 1, wherein the concentration of the functionalized and modified multi-walled carbon nanotubes in the precursor dispersion liquid in the step 3 is 1.5-6 wt%.

7. The method for preparing the flexible and stretchable silicone rubber-based wearable strain sensing fiber according to claim 1, wherein the mass ratio of the functionalized and modified multi-walled carbon nanotubes in the composite fiber obtained in the step 4 is 0.75-1.5 wt%.

8. The method of claim 1, wherein said silicone rubber component A is vinyl terminated polydimethyl-methylvinylsiloxane; the silicone rubber component B adopts dimethyl-methylhydrosiloxane and platinum catalyst.

Technical Field

The invention belongs to the technical field of polymer-based nano composite materials, and particularly relates to a preparation method of a flexible and stretchable silicon rubber-based wearable strain sensing fiber.

Background

The strain sensing material is a functional material capable of converting external stimuli such as pulling, pressing and bending into visible electric signals, and has good application prospects in human-computer interaction, flexible display screens, artificial intelligence and wearable electronic equipment. The traditional strain sensing material is usually manufactured based on rigid materials such as metal and semiconductor strain gauges, and although the traditional strain sensing material has good sensing performance and response capability, the traditional strain sensing material has the defects of complex preparation process, high cost, poor flexibility and wearability and the like, so that the application range of the traditional strain sensing material is limited. The polymer-based strain sensing material has the characteristics of good flexibility, chemical corrosion resistance, easiness in processing and forming, low cost and the like, and has the advantages of simple signal output mode, simple and convenient working mechanism and strong wearability, so that the polymer-based strain sensing material becomes a current research hotspot. However, higher loadings are generally required to achieve good conductivity and sensing properties, which severely affect the processability and mechanical properties (mainly strength and flexibility) of the composite. Therefore, how to obtain a flexible, stretchable and highly sensitive polymer-based strain sensing material at low filling becomes a problem to be solved.

Chinese patent (application number: 201710401202.0, application date: 2017-05-31, publication number: CN107287684A, publication date: 2017-10-24) discloses a preparation method of a flexible force-sensitive sensing fiber, wherein an elastic composite fiber with a highly oriented one-dimensional (1D)/two-dimensional (2D) hybrid network structure is prepared by adopting a wet spinning method, and the elastic composite fiber is further fully swelled in a metal precursor and reduced in reducing steam to prepare the force-sensitive sensing fiber based on a 0D/1D/2D three-dimensional cooperative network. Chinese patent (application No. 201720453150.7, application date: 2017-04-27, publication No. CN1.207002925A, publication date: 2018-02-13) discloses a preparation method of flexible sensing fiber, conductive fiber made of a plurality of silver-plated nylon threads is wrapped on spandex elastic yarn, and insulating material is wrapped outside the conductive fiber to prepare the flexible sensing fiber with good elasticity and conductivity. However, the flexible sensing fiber prepared in the current patent generally has the problems of high content of conductive filler, complex preparation process, high production cost and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a preparation method of a flexible and stretchable silicon rubber-based wearable strain sensing fiber, and the strain sensing fiber obtained by the method has the characteristics of low filling, flexibility, stretchability and high sensitivity.

In order to achieve the purpose, the invention adopts the technical scheme that the preparation method of the flexible and stretchable silicon rubber-based wearable strain sensing fiber is characterized by comprising the following steps of:

step 1, performing reflux reaction on a silane coupling agent in a toluene solvent protected by nitrogen atmosphere at 60-100 ℃ for 12-24 h to modify the surface of a hydroxyl multi-walled carbon nanotube, performing vacuum filtration and washing, and drying in an oven at 60-80 ℃ for 3-8 h to obtain a functionalized modified multi-walled carbon nanotube;

step 2, taking the silicone rubber component A and the silicone rubber component B, magnetically stirring for 10-40 min according to a mass ratio of 8: 1-12: 1 until the components are uniformly mixed, degassing for 10-40 min until a precursor mixed solution is bubble-free, injecting the precursor mixed solution into a polytetrafluoroethylene tube, and curing in an oven at 60-80 ℃ for 1-3 h to prepare the transparent bubble-free silicone rubber fiber with a smooth surface;

step 3, weighing the silicone rubber A component, dissolving the silicone rubber A component in a solvent, adding the functionalized modified multi-walled carbon nanotubes, uniformly dispersing, and then placing the mixture in an oven at the temperature of 60-80 ℃ to remove the solvent; adding the silicone rubber component B according to the mass ratio of the silicone rubber component A to the silicone rubber component B of 8: 1-12: 1, uniformly mixing, and degassing for 10-40 min to obtain a precursor dispersion liquid of the functionalized modified multi-walled carbon nanotube;

step 4, immersing the silicone rubber fiber prepared in the step 2 into the functional modified multi-walled carbon nanotube precursor dispersion liquid prepared in the step 3, so that the functional modified multi-walled carbon nanotube precursor dispersion liquid is coated on the surface of the silicone rubber fiber; and taking out the fiber, and curing the fiber in an oven at the temperature of 60-80 ℃ for 1-3 hours to obtain the flexible and stretchable silicon rubber-based wearable strain sensing fiber with the core-shell structure.

The silane coupling agent in the step 1 is one of KH550, KH560 and KH 570.

The concentration of the silane coupling agent in the step 1 in the toluene solution is 2-8 g/L.

The functionalized modified multi-walled carbon nanotube in the step 3 can be replaced by one of graphene, metal nanowires or metal nanoparticles.

The solvent in the step 3 is one of tetrahydrofuran, cyclohexane or n-hexanol.

The concentration of the functionalized modified multi-walled carbon nanotubes in the precursor dispersion liquid in the step 3 is 1.5-6 wt%.

In the content of the functionalized modified multi-walled carbon nanotubes in the composite fiber obtained in the step 4, the whole mass of the composite fiber accounts for 0.75-1.5 wt%.

The component A of the silicon rubber adopts vinyl-terminated polydimethyl-methylvinylsiloxane; the silicone rubber component B adopts dimethyl-methylhydrosiloxane and platinum catalyst.

Compared with the prior art, the invention has the beneficial effects that:

the flexible and stretchable silicon rubber fiber is used as a matrix, the functionalized modified multi-walled carbon nanotube is used as a functional filler, the conductive nano material precursor dispersion liquid is coated on the surface of the silicon rubber fiber by a simple and convenient low-cost dip-coating-curing method, and the flexible, stretchable and highly sensitive silicon rubber-based composite strain sensing fiber with a core-shell structure is prepared after curing. The preparation method adopted by the invention is simple and effective, has strong operation controllability and low cost, can be manufactured in a large scale and is easy for commercial production. The obtained strain sensing fiber has the characteristics of flexibility, stretchability, high sensitivity and the like, and the local effective concentration of the functionalized modified multi-walled carbon nanotube in the shell layer can be effectively improved through the core-shell structure design, so that the composite fiber is endowed with high conductivity and excellent sensing performance under low filling, and has good repeatability and working stability. Therefore, the flexible and stretchable silicon rubber-based sensing fiber disclosed by the invention has a good application prospect in the fields of resistance variable conductors, artificial intelligence, wearable equipment and the like.

The preparation method of the flexible and silicon rubber-based wearable strain sensing fiber is characterized by comprising the following steps: the invention is based on the core-shell structure design, and adopts a simple and convenient low-cost dip-coating-curing method to coat the precursor dispersion liquid of the nano conductive material and the silicon rubber on the surface of the silicon rubber fiber, so as to prepare the silicon rubber-based strain sensing fiber composite material with low filling, flexibility, stretchability and high sensitivity. The core-shell structure design enables the conductive filler to be selectively distributed in the silicone rubber matrix shell layer of the composite fiber, effectively improves the local concentration of the conductive filler in the elastomer fiber, and thus endows the composite fiber with good conductivity and sensing performance under low filling.

Drawings

FIG. 1 is a Transmission Electron Microscope (TEM) image of KH570 functionalized and modified multi-walled carbon nanotubes in example 4 of the present invention.

FIG. 2 is a cross-sectional electron Scanning Electron Microscope (SEM) image of the composite fiber in example 4 of the present invention.

FIG. 3 is a Scanning Electron Microscope (SEM) image of the shell layer of the composite fiber in example 4 of the present invention.

Fig. 4 is a photograph of the application of the composite fiber in human body movement monitoring in example 4 of the present invention.

FIG. 5 is a current response curve of the composite fiber in example 4 of the present invention for human body movement monitoring (wrist flexion-extension).

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The preparation method of the flexible and stretchable silicon rubber-based wearable strain sensing fiber comprises the following steps:

step 1, performing reflux reaction on a silane coupling agent in a toluene solvent protected by nitrogen atmosphere at 60-100 ℃ for 12-24 h to modify the surface of a hydroxyl multi-walled carbon nanotube, performing vacuum filtration and washing, and drying in an oven at 60-80 ℃ for 3-8 h to obtain a functionalized modified multi-walled carbon nanotube;

the silane coupling in the step 1 is one of KH550, KH560 and KH 570.

The concentration of the silane coupling agent in the toluene solution in the step 1 is 2-8 g/L.

Step 2, taking a silicone rubber component A (vinyl-terminated polydimethyl-methyl vinyl siloxane) and a silicone rubber component B (polydimethyl-methyl hydrogen siloxane and a platinum catalyst), magnetically stirring for 10-40 min according to the mass ratio of 8: 1-12: 1 until the components are uniformly mixed, degassing for 10-40 min until a precursor mixed solution is bubble-free, injecting the precursor mixed solution into a polytetrafluoroethylene tube, and curing in an oven at 60-80 ℃ for 1-3 h to prepare the transparent bubble-free silicone rubber fiber with a smooth surface;

step 3, weighing a proper amount of silicone rubber component A (vinyl-terminated polydimethyl-methylvinylsiloxane) to dissolve in a solvent, adding the functionalized modified multi-walled carbon nanotubes to disperse uniformly, and then placing in an oven at 60-80 ℃ to remove the solvent; adding the silicone rubber component B (dimethyl-methyl hydrogen siloxane and platinum catalyst) according to the mass ratio of the silicone rubber component A (vinyl-terminated dimethyl-methyl vinyl siloxane) to the silicone rubber component B (dimethyl-methyl hydrogen siloxane and platinum catalyst) of 8: 1-12: 1, uniformly mixing, and degassing for 10-40 min to obtain a precursor dispersion liquid of the functionalized modified multi-walled carbon nanotube; the solvent in the step 3 is one of tetrahydrofuran, cyclohexane or n-hexanol;

the functionalized modified multi-walled carbon nanotube in the step 3 can be replaced by one of graphene, metal nanowires or metal nanoparticles.

Step 4, immersing the silicone rubber fiber prepared in the step 2 into the functional modified multi-walled carbon nanotube precursor dispersion liquid prepared in the step 3, so that the precursor dispersion liquid is coated on the surface of the silicone rubber fiber; and taking out the fiber and then placing the fiber in an oven at the temperature of 60-80 ℃ for curing for 1-3 h to obtain the flexible and stretchable silicon rubber-based wearable strain sensing fiber with the core-shell structure, wherein the content of the functionalized modified multi-walled carbon nanotubes is 0.75-1.5 wt%.