Preparation technology of flexible self-powered sensor based on oriented nanofiber bundle

Abstract

The invention discloses a preparation technology of a flexible self-energized sensor based on an oriented nanofiber bundle, the oriented TPU fiber bundle (HTB) with multilevel morphology is prepared through a water-assisted electrostatic spinning technology, and a formation mechanism and a regulation and control means of the multilevel morphology of the HTB are explored. Ecoflex is selected as a friction negative electrode material to prepare the HTB-based TENG. The HTB is woven into the fabric, the fabric, the Ecoflex and the PET are assembled into the high-sensitivity self-powered pressure sensor (HSPS), the high-sensitivity self-powered pressure sensor can collect mechanical energy of human motion, the good sensing performance is achieved, and pulse signals of the human body can be effectively monitored. The preparation technology has a wide application prospect in the field of self-powered flexible wearable sensing devices.

Description

Technical Field

[0001] The invention relates to a preparation technology of a flexible self-powered sensor based on oriented nanofiber bundles, which can be used in the field of flexible wearable self-powered sensors. Background Art

[0002] The rapid development of science and technology has made the Internet of Things technology gradually mature, and sensors are an indispensable part of the Internet of Things. Self-powered sensors have attracted widespread attention due to their portability, environmental protection, and low cost. Flexible self-powered sensors have excellent flexibility, good mechanical properties, and lightness, so the research on TENG-based flexible self-powered sensors is very meaningful.

[0003] Fabric-based self-powered sensors have good flexibility, deformability, washability, breathability, and wear comfort, and have been widely studied. Fan et al. prepared a full-fabric TENG-based self-powered sensor. This sensor has good wear comfort and pressure sensitivity. The sensitivity reached 7.84mV / Pa, the response time reached 20ms, and the sensing performance remained stable after 100,000 cycles. Lou et al. prepared a TENG-based self-powered sensor by weaving core-shell structured fibers into fabrics. The sensitivity of this sensor reached 133V / kPa and 0.32V / kPa in the working ranges of 1.95-3.13kPa and 3.20-4.61kPa, respectively, and the sensing performance could be maintained without degradation after 4200 cycles or 4h of washing. Generally, fabric-based self-powered sensors are composed of functional 1D yarns, which can be directly woven on existing fabrics or directly woven into fabrics. Therefore, it is very important to prepare continuous fibers. Smit et al.

[93] electrospun on a water collector and prepared fiber bundle yarns of polyvinylidene fluoride, polyvinyl acetate and polyacrylonitrile by traction. These yarns can be prepared continuously and have a good oriented structure. Summary of the invention

[0004] The present invention prepares thermoplastic polyurethane (TPU) fiber bundle yarn (HTB) with multi-level orientation morphology by water-assisted electrospinning technology, and prepares a self-powered pressure sensor (HSPS) based on HTB.

[0005] The technical purpose of the present invention is achieved through the following technical solutions.

[0006] A preparation technology of a flexible self-powered sensor based on oriented nanofiber bundles is carried out according to the following steps:

[0007] Step 1, preparation of oriented nanofiber bundles (HTB):

[0008] Add thermoplastic polyurethane (TPU) particles to a mixed solvent (18%, w / w) of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) (1:1), and set aside after the TPU is completely dissolved and mixed evenly. Add the prepared mixed solution into a 10 ml syringe for water-assisted electrospinning, and use a glass container filled with water (water depth 20 mm) as a fiber collection device. The spinning voltage is 16 kV, the syringe does not move at a fixed position, and the vertical distance between the syringe nozzle and the water surface is 20 cm. After the fiber film is formed on the water surface, a glass rod is used to pull the fiber out of the water to form an oriented fiber bundle yarn, and one end of the pulled fiber bundle yarn is wound around a rotating drum to continuously collect the fiber bundle yarn.

[0009] Step 2, preparation of HTB-based triboelectric nanogenerator (TENG):

[0010] HTB was cut into 4 cm lengths and a copper electrode was attached to one side. Glue A and glue B were mixed in equal proportions and introduced into the template and heated in an oven. After curing, Ecoflex (thickness 100 μm) was obtained. HTB with electrodes and Ecoflex were assembled into TENG.

[0011] Step 3, preparation of TENG-based self-powered pressure sensor based on HTB:

[0012] 2mm wide HTB was selected to be interlaced and woven into a 7×7 fabric. The woven fabric was glued to the PET film with double-sided tape as the lower structure of the self-powered pressure sensor (HSPS). The homemade Ecoflex (00-30) was glued to the surface of the polyethylene terephthalate (PET) film with aluminum (Al) electrodes as the upper structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The morphologies of oriented fiber bundles of different sizes.

[0014] Figure 2 Schematic diagram of the structure of HSPS.

[0015] Figure 3 It is the wrist pulse signal monitored by HSPS.

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

[0017] Example 1

[0018] 1) Preparation of oriented nanofiber bundles (HTB): Add thermoplastic polyurethane (TPU) particles to a mixed solvent (18%, w / w) of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF) (1:1), and set aside after the TPU is completely dissolved and mixed evenly. Add the prepared mixed solution into a 10 ml syringe for water-assisted electrospinning, and use a glass container filled with water (water depth 20 mm) as a fiber collection device. The spinning voltage is 16 kV, the syringe does not move at a fixed position, and the vertical distance between the syringe nozzle and the water surface is 20 cm. After the fiber film is formed on the water surface, a glass rod is used to pull the fiber out of the water to form an oriented fiber bundle yarn, and one end of the pulled fiber bundle yarn is wound around a rotating drum to continuously collect the fiber bundle yarn.

[0019] 2) Preparation of HTB-based triboelectric nanogenerator (TENG): HTB was cut into 4 cm lengths and a copper electrode was attached to one side. Glue A and glue B were mixed in equal proportions and introduced into the template and heated in an oven. Ecoflex (100 μm thick) was obtained after curing. HTB with electrodes and Ecoflex were assembled into TENG.

[0020] 3) Preparation of TENG-based self-powered pressure sensor based on HTB: 2 mm wide HTB was selected and woven into a 7×7 fabric. The woven fabric was glued to the PET film with double-sided tape as the lower structure of the self-powered pressure sensor (HSPS). The homemade Ecoflex (00-30) was glued to the surface of the polyethylene terephthalate (PET) film with aluminum (Al) electrodes as the upper structure.

[0021] Example 2

[0022] 1) Preparation of oriented nanofiber bundles (HTB): TPU solution is used as the spinning solution, and the static water surface is used as the receiving device for electrospinning. The syringe does not move at a fixed position. After the fiber film is formed on the water surface, a glass rod is used to pull the fiber out of the water surface to form an oriented fiber bundle yarn, and the pulled fiber bundle yarn is collected.

[0023] 2) Preparation of HTB-based triboelectric nanogenerator (TENG): HTB was cut into different lengths and assembled with Ecoflex with electrodes to form a TENG.

[0024] 3) Preparation of TENG-based self-powered pressure sensor based on HTB: HTB was interlaced into fabric and adhered to PET film with double-sided tape as the lower structure of the self-powered pressure sensor (HSPS). Homemade Ecoflex (00-30) was adhered to the surface of polyethylene terephthalate (PET) film with aluminum (Al) electrodes as the upper structure.

[0025] Example 3

[0026] 1) Preparation of oriented nanofiber bundles (HTB): Add thermoplastic polyurethane (TPU) particles to a mixed solvent (18%, w / w) of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF) (1:1), and set aside after the TPU is completely dissolved and mixed evenly. Add the prepared mixed solution into a 10 ml syringe for water-assisted electrospinning, and use a glass container filled with water (water depth 20 mm) as a fiber collection device. The spinning voltage is 16 kV, the syringe does not move at a fixed position, and the vertical distance between the syringe nozzle and the water surface is 20 cm. After the fiber film is formed on the water surface, a glass rod is used to pull the fiber out of the water to form an oriented fiber bundle yarn, and one end of the pulled fiber bundle yarn is wound around a rotating drum and the fiber bundle yarn is continuously collected.

[0027] 2) Preparation of HTB-based triboelectric nanogenerator (TENG): HTBs of different sizes were cut into the same length using scissors and assembled with Ecoflex with electrodes into a single-electrode TENG. The triboelectric performance was tested to select the HTB with the best performance.

[0028] 3) Preparation of TENG-based self-powered pressure sensor based on HTB: HTB was interlaced into fabric and adhered to PET film with double-sided tape as the lower structure of the self-powered pressure sensor (HSPS). The homemade Ecoflex (00-30) was adhered to the surface of polyethylene terephthalate (PET) film with aluminum (Al) electrodes as the upper structure to obtain a highly sensitive TENG-based self-powered pressure sensor.

[0029] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A preparation technology for a flexible self-powered sensor based on oriented nanofiber bundles, its characteristics and The preparation steps are as follows: 1) Preparation of oriented nanofiber bundles (HTB): Add thermoplastic polyurethane (TPU) particles to a mixed solvent (18%, w / w) of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF) (1:1), and set aside after the TPU is completely dissolved and mixed evenly. Add the prepared mixed solution into a 10 ml syringe for water-assisted electrospinning, and use a glass container filled with water (water depth 20 mm) as a fiber collection device. The spinning voltage is 16 kV, the syringe does not move at a fixed position, and the vertical distance between the syringe nozzle and the water surface is 20 cm. After the fiber film is formed on the water surface, a glass rod is used to pull the fiber out of the water to form an oriented fiber bundle yarn, and one end of the pulled fiber bundle yarn is wound around a rotating drum to continuously collect the fiber bundle yarn. 2) Preparation of HTB-based triboelectric nanogenerator (TENG): HTB was cut into 4 cm lengths and a copper electrode was attached to one side. Glue A and glue B were mixed in equal proportions and introduced into the template and heated in an oven. Ecoflex (thickness 100 μm) was obtained after curing. HTB with electrodes and Ecoflex were assembled into TENG. 3) Preparation of TENG-based self-powered pressure sensor based on HTB: 2 mm wide HTB was selected and woven into a 7×7 fabric. The woven fabric was glued to the PET film with double-sided tape as the lower structure of the self-powered pressure sensor (HSPS). The homemade Ecoflex (00-30) was glued to the surface of the polyethylene terephthalate (PET) film with aluminum (Al) electrodes as the upper structure.

2. The preparation method according to step 1) in claim 1, characterized in that: Use a glass rod to pull the floating nanofiber membrane in one direction. The fiber membrane will move in the pulling direction and drive the newly fallen fibers to form a continuous ribbon fiber membrane on the water surface. The moving fiber membrane will be partially oriented along the pulling direction under the action of the water surface resistance. When the fiber membrane is pulled out of the water, it collapses into HTB due to the instantaneous loss of surface tension of the water surface. When the pulling speed is such that the number of supplemented fibers is the same as the number of fibers forming the fiber bundle at the same time, HTB with continuous length and uniform thickness will be continuously obtained.

3. The preparation method according to step 2) in claim 1, characterized in that: HTBs of different sizes were cut into 4 cm lengths and affixed with conductive copper tape on one side as electrodes. The HTBs were then fixed on an acrylic plate and assembled with the homemade Ecoflex to form a single-electrode TENG (H-TENG).

4. The preparation method according to step 3) in claim 1, characterized in that: 1.5-HTB was woven into a 7×7 fabric array and assembled with Ecoflex and PET support layers to form HSPS. The 1.5-HTB woven layer not only served as a friction layer of HSPS, but also as a spacer layer.

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