A flexible wearable sensor material for motion monitoring, and a method of making and use thereof in wearable sensors

Abstract

The application relates to the technical field of high polymer material preparation, and particularly discloses a flexible wearable sensor material for motion monitoring, a preparation method thereof and application of the flexible wearable sensor material in preparation of a wearable sensor. The preparation method of the flexible wearable sensor material for motion monitoring comprises the following steps: mixing epoxy soybean oil and 3-(4-carboxyl phenyl) propionic acid, stirring at 130-150 DEG C for 30-60 minutes to obtain a mixture A; mixing borax and glycerol to obtain a mixture B; adding the mixture B into the mixture A, stirring at 130-150 DEG C for 40-80 minutes to obtain a mixture C; cooling the mixture C to 40-60 DEG C, dissolving by adding a solvent, then pouring into a mold, and solidifying to obtain a flexible material, namely the flexible wearable sensor material for motion monitoring. The material has the advantages of easy processing, easy degradation, strong self-healing capacity, good biocompatibility, excellent mechanical properties and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material preparation, in particular to a flexible wearable sensor material for motion monitoring and a preparation method thereof and application thereof in preparing wearable sensors. BACKGROUND

[0002] Whether it is daily commuting work or physical exercise, joint injury seems to be a problem that people of all ages will face, and how to prevent the occurrence of this disease in a scientific way has become a very meaningful topic. At present, the main means for monitoring human motion is through the clothes with sensors, real-time cameras, and the posture of human motion is converted into three-dimensional modeling form to the computer for analysis and processing. Here we face the problems of inconvenient wearing, high cost of equipment, limited use of places, low sensitivity and other shortcomings. In recent years, strain sensors have attracted people's research interest due to their good flexibility, good sensitivity, portability and good adaptability, and strain sensors have been widely used in wearable portable devices. High stretchability and sensitivity are one of the most important factors of strain sensors.

[0003] At present, although great progress has been made in the development of high-stretchable and high-sensitivity flexible sensors, there are still great limitations that hinder their application. The reported flexible strain sensors have a complicated preparation process, and the materials cannot be degraded. The wide application of the sensors and improper post-processing can cause serious environmental pollution. SUMMARY

[0004] In order to overcome at least one of the technical problems in the prior art, the present application first provides a flexible wearable sensor material for motion monitoring and a preparation method thereof and application thereof in preparing wearable sensors.

[0005] The technical solution of the present application is as follows:

[0006] The present application first provides a preparation method of a flexible wearable sensor material for motion monitoring, which comprises the following steps:

[0007] Take the epoxy soybean oil and 3-(4-carboxylphenyl) propionic acid, mix and stir at 130-150℃ for 30-60 minutes to obtain mixture A;

[0008] Take borax and glycerol to mix to obtain mixture B;

[0009] Add mixture B to mixture A, stir at 130-150℃ for 40-80 minutes to obtain mixture C;

[0010] Cooling the mixture C to 40~60℃, dissolving with solvent, then pouring into a mold, and after solidification, the flexible material, i.e. the flexible wearable sensor material for motion monitoring is obtained.

[0011] Preferably, the weight ratio of the epoxy soybean oil and 3-(4-carboxyphenyl)propionic acid is 10:8~9.

[0012] Most preferably, the weight ratio of the epoxy soybean oil and 3-(4-carboxyphenyl)propionic acid is 10:8.4.

[0013] Preferably, the weight ratio of the borax and glycerol is 2~3:6~7.

[0014] Most preferably, the weight ratio of the borax and glycerol is 2.5:6.3.

[0015] Preferably, the method for preparing the flexible wearable sensor material for motion monitoring further comprises the following step:

[0016] Immersing the flexible material in the carbon nanotube solution for more than 2 seconds, and then drying to obtain the flexible wearable sensor material for motion monitoring.

[0017] Further preferably, immersing the flexible material in the carbon nanotube solution for more than 2 seconds, and then drying; repeating the step for 2~5 times to obtain the flexible wearable sensor material for motion monitoring.

[0018] Most preferably, immersing the flexible material in the carbon nanotube solution for 3 seconds, and then drying; repeating the step for 3 times to obtain the flexible wearable sensor material for motion monitoring.

[0019] Preferably, the carbon nanotube solution is prepared by the following method:

[0020] Taking sodium carboxymethyl cellulose and adding it to water to obtain a sodium carboxymethyl cellulose solution;

[0021] Taking carbon nanotubes and adding them to the sodium carboxymethyl cellulose solution, and then stirring uniformly to obtain the carbon nanotube solution.

[0022] Further preferably, the amount ratio of the sodium carboxymethyl cellulose to water is 0.3~0.6 g:50 ml.

[0023] Most preferably, the amount ratio of the sodium carboxymethyl cellulose to water is 0.5 g:50 ml.

[0024] Further preferably, taking sodium carboxymethyl cellulose and calcium dodecylbenzenesulfonate and adding them to water to obtain a sodium carboxymethyl cellulose solution;

[0025] Further preferably, the use amount ratio of sodium carboxymethyl cellulose, calcium dodecylbenzenesulfonate and water is 0.3-0.4 g:0.1-0.2 g:50 ml.

[0026] Most preferably, the use amount ratio of sodium carboxymethyl cellulose, calcium dodecylbenzenesulfonate and water is 0.35 g:0.15 g:50 ml.

[0027] Preferably, the mass fraction of carbon nanotubes in the sodium carboxymethyl cellulose solution is 0.4-1.2 wt.%.

[0028] Most preferably, the mass fraction of carbon nanotubes in the sodium carboxymethyl cellulose solution is 0.8 wt.%.

[0029] The application further provides a flexible wearable sensor material for motion monitoring prepared by the above preparation method.

[0030] The application further provides application of the above flexible wearable sensor material for motion monitoring in preparation of a wearable sensor.

[0031] Preferably, the preparation method of the wearable sensor is: cutting the flexible wearable sensor material for motion monitoring into a strip, then coating conductive silver paste on both ends of the strip, and assembling the wearable sensor with a wire.

[0032] Advantages

[0033] (1) The flexible wearable sensor material for motion monitoring is a bio-based polymer material, has a good degradation rate in a polar solvent, can be recycled and reused, and is a green and environmentally friendly material.

[0034] (2) The sensor prepared from the flexible wearable sensor material for motion monitoring is also good in electrochemical stability and signal response performance, and the resistance signal of the sensor does not attenuate after 50 cycles under a 20% strain; the sensor material has high sensitivity, and the resistance of the material is only 700-2000 Ω, and the material with low resistance has broad application prospects, such as some human-machine interaction devices.

[0035] (3) In addition, the flexible wearable sensor material for motion monitoring has a strong self-healing ability, and after the material is broken, the original mechanical properties and sensing performance are almost not affected after self-healing at room temperature, can perfectly adapt to the scene requiring frequent stretching in sensor application, and the self-healing ability has a significant advantage compared with the same type of polyurethane material. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A resistance change rate graph for the wearable sensor of the present application applied to a human elbow joint.

[0037] Figure 2 A resistance change rate graph for the wearable sensor of the present application applied to a human elbow joint. DETAILED DESCRIPTION

[0038] The present application will be further explained in connection with specific embodiments, but the embodiments do not limit the present application in any form.

[0039] Example 1: Preparation of a flexible wearable sensor material for motion monitoring

[0040] (1) Epoxy soybean oil (10 g) and 3-(4-carboxyphenyl)propionic acid (8.4 g) were added into a 250 ml three-necked flask and mechanically stirred in an oil bath at 140°C for 40 minutes to obtain mixture A;

[0041] (2) Borax (2.5 g) was dissolved in glycerol (6.3 g) to obtain mixture B;

[0042] (3) Mixture B was added into the three-necked flask containing mixture A, and stirring was continued for 1 hour at 140°C under mechanical stirring to obtain mixture C;

[0043] (4) Mixture C was cooled to 50°C, and 20 ml of acetone was added for dissolution, followed by pouring into a polytetrafluoroethylene mold and curing in an oven at 140°C for 10 hours to obtain a flexible material, i.e., the flexible wearable sensor material for motion monitoring.

[0044] Example 2: Preparation of a flexible wearable sensor material for motion monitoring

[0045] (1) Epoxy soybean oil (10 g) and 3-(4-carboxyphenyl)propionic acid (8.4 g) were added into a 250 ml three-necked flask and mechanically stirred in an oil bath at 140°C for 40 minutes to obtain mixture A;

[0046] (2) Borax (2.5 g) was dissolved in glycerol (6.3 g) to obtain mixture B;

[0047] (3) Mixture B was added into the three-necked flask containing mixture A, and stirring was continued for 1 hour at 140°C under mechanical stirring to obtain mixture C;

[0048] (4) Mixture C was cooled to 50°C, and 20 ml of acetone was added for dissolution, followed by pouring into a polytetrafluoroethylene mold and curing in an oven at 140°C for 10 hours to obtain a flexible material;

[0049] (5) the flexible material is immersed in the carbon nanotube solution for 3 seconds, and then is placed in a 60°C air drying oven for drying for 20 minutes; the step is repeated for 3 times, to obtain the flexible wearable sensor material for motion monitoring;

[0050] The carbon nanotube solution is prepared by the following method:

[0051] Sodium carboxymethyl cellulose (0.5 g) is weighed and added into 50 ml of water to prepare a sodium carboxymethyl cellulose solution; carbon nanotubes are added into the sodium carboxymethyl cellulose solution at an addition amount of 0.8 wt.%, and stirring is continued for 1 hour, and ultrasonic treatment is performed for 2 hours, to obtain the carbon nanotube solution.

[0052] Example 3: Preparation of a flexible wearable sensor material for motion monitoring

[0053] (1) epoxy soybean oil (10 g) and 3-(4-carboxylphenyl)propionic acid (8.4 g) are added into a 250 ml three-necked flask, and mechanical stirring is performed in an oil bath at 140°C for 40 minutes; mixture A is obtained;

[0054] (2) borax (2.5 g) is dissolved in glycerol (6.3 g) to obtain mixture B;

[0055] (3) mixture B is added into the three-necked flask containing mixture A, and stirring is continued for 1 hour under mechanical stirring at 140°C, to obtain mixture C;

[0056] (4) mixture C is cooled to 50°C, and is kept at the temperature, and is dissolved in 20 ml of acetone, and then is poured into a polytetrafluoroethylene mold, and is placed in an oven at 140°C for curing for 10 hours to obtain the flexible material;

[0057] (5) the flexible material is immersed in the carbon nanotube solution for 3 seconds, and then is placed in a 60°C air drying oven for drying for 20 minutes; the step is repeated for 3 times, to obtain the flexible wearable sensor material for motion monitoring;

[0058] The carbon nanotube solution is prepared by the following method:

[0059] Sodium carboxymethyl cellulose (0.35 g) and calcium dodecylbenzenesulfonate (0.15 g) are weighed and added into 50 ml of water to prepare a sodium carboxymethyl cellulose solution; carbon nanotubes are added into the sodium carboxymethyl cellulose solution at an addition amount of 0.8 wt.%, and stirring is continued for 1 hour, and ultrasonic treatment is performed for 2 hours, to obtain the carbon nanotube solution.

[0060] Comparative Example 1: Preparation of a flexible wearable sensor material for motion monitoring

[0061] (1) Epoxy soybean oil (10 g) and 3-(4-carboxyphenyl)propionic acid (8.4 g) were added into a 250 ml three-necked flask and mechanically stirred at 140°C for 40 minutes in an oil bath; mixture A was obtained;

[0062] (2) Borax (2.5 g) was dissolved in glycerol (6.3 g) to obtain mixture B;

[0063] (3) Mixture B was added into the three-necked flask containing mixture A, and mechanically stirred at 140°C for 1 hour to obtain mixture C;

[0064] (4) Mixture C was cooled to 50°C, and then dissolved in 20 ml of acetone, and then poured into a polytetrafluoroethylene mold and cured in an oven at 140°C for 10 hours to obtain a flexible material;

[0065] (5) The flexible material was immersed in a carbon nanotube solution for 3 seconds, and then dried in a 60°C air-drying oven for 20 minutes; the above step was repeated 3 times to obtain a flexible wearable sensor material for motion monitoring;

[0066] The carbon nanotube solution was prepared by the following method:

[0067] Carbon nanotubes were weighed and added to water at an addition amount of 0.8 wt.%, and continuously stirred for 1 hour and ultrasonically treated for 2 hours to obtain a carbon nanotube solution.

[0068] Table 1: Performance test results of the flexible wearable sensor material for motion monitoring of the present application

[0069]

[0070] The specific steps of the relative resistance change experiment of the sensor under different strains are as follows:

[0071] The electromechanical properties of the strain sensor were measured by a digital multimeter (Keithley 2401) and a CHI760E workstation (CHInstruments, Austin, TX, USA). When a certain stress was applied to the flexible sensor, the resistance value of the sensor would change accordingly.

[0072] The gauge factor (GF) is considered to be an important parameter for quantitatively evaluating the sensitivity of the sensor, and represents the typical strain relative resistance response law. GF can be expressed by the following equation:

[0073]

[0074] As can be seen from the experimental data in Table 1, the flexible material prepared from the epoxy soybean oil, 3-(4-carboxyl phenyl) propionic acid and borax as raw materials has good tensile stress and elongation at break.

[0075] As can be seen from the experimental data in Table 1, the GF value of the flexible wearable sensor material for motion monitoring prepared in Example 2 is significantly higher than that of the flexible wearable sensor material for motion monitoring prepared in Example 1, which shows that the flexible wearable sensor material for motion monitoring prepared by further dipping the flexible material prepared from the epoxy soybean oil, 3-(4-carboxyl phenyl) propionic acid and borax as raw materials in the carbon nanotube solution of the application can significantly improve the sensitivity of the flexible wearable sensor material for motion monitoring.

[0076] As can be seen from the experimental data in Table 1, the GF value of the flexible wearable sensor material for motion monitoring prepared in Comparative Example 1 is not significantly improved compared with Example 1, which shows that the preparation of the carbon nanotube solution of the application is very critical; the flexible material must be further dipped in the carbon nanotube solution added with sodium carboxymethyl cellulose to significantly improve the sensitivity of the flexible wearable sensor material for motion monitoring.

[0077] As can be seen from the experimental data in Table 1, the GF value of the flexible wearable sensor material for motion monitoring prepared in Example 3 is significantly higher than that of the flexible wearable sensor material for motion monitoring prepared in Example 1, and also significantly higher than that of the flexible wearable sensor material for motion monitoring prepared in Example 2, which shows that the flexible material further dipped in the carbon nanotube solution added with sodium carboxymethyl cellulose and calcium dodecylbenzenesulfonate can significantly improve the sensitivity of the flexible wearable sensor material for motion monitoring; and the degree of improvement in the sensitivity of the flexible wearable sensor material for motion monitoring is also significantly higher than that of the flexible wearable sensor material for motion monitoring prepared by dipping in the carbon nanotube solution added with only sodium carboxymethyl cellulose.

[0078] Example 4: Preparation of wearable sensor

[0079] The flexible wearable sensor material for motion monitoring described in Example 1, 2 or 3 is cut into a rectangular strip (30 mm x 10 mm x 0.4 mm), silver conductive paste is applied to both ends of the strip, and copper wire is assembled to obtain a wearable sensor.

[0080] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application shall be equivalent replacement manners and shall be included in the protection scope of the present application.

Claims

1. A method for preparing a flexible wearable sensor material for motion monitoring, characterized in that, comprising the following steps: mixing epoxy soybean oil and 3-(4-carboxylphenyl) propionic acid, stirring at 130-150 ℃ for 30-60 min to obtain mixture A; mixing borax and glycerol to obtain mixture B; adding mixture B to mixture A, stirring at 130-150 ℃ for 40-80 min to obtain mixture C; cooling mixture C to 40-60 ℃, dissolving by adding a solvent, then pouring into a mold, and solidifying to obtain a flexible material; immersing the flexible material in a carbon nanotube solution for more than 2 seconds, then taking it out and drying; repeating the step 2-5 times to obtain the flexible wearable sensor material for motion monitoring; the carbon nanotube solution is prepared by the following method: adding sodium carboxymethyl cellulose to water to obtain a sodium carboxymethyl cellulose solution; adding carbon nanotubes to the sodium carboxymethyl cellulose solution, stirring uniformly to obtain the carbon nanotube solution; wherein the ratio of sodium carboxymethyl cellulose to water is 0.3-0.6 g: 50 ml; the mass fraction of carbon nanotubes in the sodium carboxymethyl cellulose solution is 0.4-1.2 wt.%.

2. The method of claim 1, wherein the flexible wearable sensor material for motion monitoring is prepared by, The weight ratio of epoxy soybean oil to 3-(4-carboxylphenyl) propionic acid is 10:8-9.

3. The method of claim 1, wherein the flexible wearable sensor material for motion monitoring is prepared by, The weight ratio of borax to glycerol is 2-3:6-7.

4. The method of claim 1, wherein, immersing the flexible material in a carbon nanotube solution for 3 seconds, then taking it out and drying; repeating the step 3 times to obtain the flexible wearable sensor material for motion monitoring. 5.The flexible wearable sensor material for motion monitoring prepared by the method of any one of claims 1-4. 6.The flexible wearable sensor material for motion monitoring of claim 5 in the preparation of a wearable sensor.

7. Use according to claim 6, characterized in that, The preparation method of the wearable sensor is: cutting the flexible wearable sensor material for motion monitoring into a strip, then coating conductive silver paste on both ends of the strip, and assembling with a wire to obtain a biosensor.

Images