Preparation method of fiber-based stress-strain sensor based on electrostatic spinning

Abstract

According to the invention, the electrospun nanofiber membrane is used as a substrate to attach a conductive material MXene, so that the piezoresistive sensing function and the attached performance of the nanofiber membrane are obtained at the same time. A complete fiber-based stress-strain sensor is constructed by taking nylon yarns as an inner core, a nanofiber membrane as an adhesion substrate and an additional functional layer, MXene as a conductive layer and PDMS as a protective layer.

Description

Technical Field

[0001] The invention relates to a method for preparing a fiber-based stress-strain sensor based on electrostatic spinning, and belongs to the field of composite materials. Background Art

[0002] Wearable technology is considered to be an innovative technology with the potential for real-time nondestructive testing, while making up for the shortcomings of traditional sensors such as poor flexibility, large size and poor portability. In recent years, wearable pressure sensors have shown good application potential in the fields of human motion detection, health monitoring, disease prevention and electronic skin due to their ability to sense, analyze and convert external pressure signals into electrical signals that are easier to capture. Fiber-based sensors are an important component of wearable devices because the shape of the fibers allows them to be more easily integrated into wearable devices.

[0003] Pressure sensors can be divided into piezoelectric, capacitive, friction and piezoresistive sensors according to their working mechanisms. Among these four types of sensors, piezoresistive sensors have attracted much attention due to their convenient preparation, simple readout mechanism, low power consumption and convenient signal acquisition. Many different nanostructured materials, including nanowires, nanoparticles, nanobelts, carbon black, carbon nanotubes and graphene, have been explored to construct stretchable piezoresistive sensors on elastomeric substrates.

[0004] As an important branch of one-dimensional nanomaterials, nanofibers have broad application prospects. Electrospinning technology is an effective method for preparing one-dimensional nanofibers. Moreover, due to its simple manufacturing equipment and low spinning cost, it can prepare continuous long-sized organic, inorganic, organic / inorganic composite, hollow or solid nanofibers, etc., which has attracted widespread attention from researchers. Since the electrospinning process solidifies into fibers through high-speed stretching and solvent volatilization, the one-dimensional nanomaterials prepared by electrospinning are generally non-woven nanofiber felts or nanofiber membranes. The preparation of piezoresistive sensors based on nanofiber membranes can make them have the relevant properties brought by nanofiber membranes (such as using piezoelectric materials to prepare nanofiber membranes, which can also have piezoelectric sensing functions).

[0005] Therefore, it is of great significance to design and prepare a fiber-based sensor that is portable, biocompatible, and capable of stress-strain sensing and can have other additional functions as needed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a fiber-based stress and strain sensor based on electrospinning, using an electrospun nanofiber membrane as a substrate to attach a conductive material MXene, so as to simultaneously obtain the piezoresistive sensing function and the incidental properties of the nanofiber membrane.

[0007] The present invention adopts the following technical solution:

[0008] The present invention relates to a method for preparing a fiber-based stress-strain sensor based on electrospinning, and the steps are as follows:

[0009] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0010] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle with a length of 10 cm and a width of 2 to 6 cm, rolled onto a 10 cm long commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution for ultrasonic treatment for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

[0011] Preferably, the concentration of the spinning solution in step 1) is 8%, 10%, or 12%.

[0012] Preferably, in step 2), the thickness of the silver-plated nylon yarn is 200-800D.

[0013] The present invention uses electrospun nanofiber membrane as a substrate to attach conductive material MXene to simultaneously obtain piezoresistive sensing function and nanofiber membrane incidental performance. A complete fiber-based stress and strain sensor is constructed using nylon yarn as the inner core, nanofiber membrane as the attachment substrate and additional functional layer, MXene as the conductive layer, and PDMS as the protective layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The stress-strain curve of the sensor stretched to 20% strain at a tensile rate of 5 mm / min

[0015] Figure 2 The resistance change diagram of the sensor when stretched to 20% strain at a stretching rate of 5 mm / min; DETAILED DESCRIPTION

[0016] Six embodiments of the present invention are given below to further illustrate the present invention, but not to limit the scope of the present invention.

[0017] Example 1

[0018] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into 8%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0019] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 2 cm in width, rolled onto a 10 cm long 200D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution and ultrasonically treated for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

[0020] Example 2

[0021] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into 8%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0022] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 2 cm in width, rolled onto a 10 cm long 400D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution for ultrasonic treatment for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

[0023] Example 3

[0024] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a 10%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0025] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 2 cm in width, rolled onto a 10 cm long 200D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution and ultrasonically treated for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

[0026] Example 4

[0027] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a 10%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0028] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 4 cm in width, rolled onto a 10 cm long 200D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution for 30 min, and dried at 60 °C for 30 min. It was then immersed in PDMS and dried at 60 °C for 1 h.

[0029] Example 5

[0030] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a 12%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0031] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 2 cm in width, rolled onto a 10 cm long 800D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution and ultrasonically treated for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

[0032] Example 6

[0033] 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a 12%wt spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h;

[0034] 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle of 10 cm in length and 2 cm in width, rolled onto a 10 cm long 400D commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution for ultrasonic treatment for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

Claims

1. A method for preparing a fiber-based stress-strain sensor based on electrospinning, characterized in that The preparation steps are as follows: 1) Preparation of nanofiber membrane: A mixed solvent (acetone:DMF=3:2) and polymer PVDF were prepared into a spinning solution, and electrospinning was performed at a spinning voltage of 18 kV, a needle distance of 20 cm, and a propulsion speed of 1.5 mL / h; 2) Preparation of sensor: The nanofiber membrane described in step 1) was cut into a rectangle with a length of 10 cm and a width of 2 to 6 cm, rolled onto a 10 cm long commercial nylon yarn, surface treated with ethanol, immersed in a 2 mg / mL MXene aqueous solution for ultrasonic treatment for 30 min, dried at 60 °C for 30 min, immersed in PDMS, and dried at 60 °C for 1 h.

2. The preparation method according to claim 1, characterized in that The concentration of the spinning solution in step 1) is 8%, 10% and 12%.

3. The preparation method according to claim 1, characterized in that In step 1), the thickness of the silver-plated nylon yarn is 200-800D.

4. According to the preparation method of claim 1, a fiber-based stress-strain sensor based on electrospinning is obtained, characterized in that The electrospun nanofiber membrane is used as a substrate to attach the conductive material MXene to simultaneously obtain the piezoresistive sensing function and the incidental properties of the nanofiber membrane.

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