Nanofiber smart conductive composite yarn with negative poisson's ratio structure and preparation method thereof

Abstract

The application relates to a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure and a preparation method thereof. A long strip-shaped insulating electrostatic spinning nanofiber film is spirally coated on the surface of a conductive core yarn to prepare a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure. Under the action of an axial tensile load, the intelligent conductive composite yarn has a negative Poisson's ratio effect, can realize the switching of the surface electrostatic spinning nanofiber film from a sheet shape to a linear shape, and simultaneously realizes the switching of the internal conductive core yarn from insulation to conduction on the surface of the composite yarn. The intelligent conductive composite yarn can be widely applied to flexible strain sensors for monitoring the changes of human joint activities.

Description

Technical Field

[0001] This invention belongs to the field of functional yarns and relates to a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure. Background Technology

[0002] With the rapid development of smart wearable technology, the demand for flexible strain sensors that can bend, stretch, and recover to monitor physiological conditions is increasing. Textile strain sensors, as the most important flexible strain sensors, can reflect the state of human physiological activity by causing changes in resistance or capacitance through deformation. Textile-based sensors mainly include fabric-based and yarn-based sensors. Among them, yarn-based sensors not only have better flexibility but also offer more flexible product design and have broad application prospects.

[0003] Patent publication (CN101728005A) discloses a pressure-sensitive conductive yarn, which includes a core yarn formed of elastic yarn and a conductive winding yarn wound around the core yarn. The winding yarn is a blend of stainless steel fiber and non-conductive fiber, capable of detecting different bio-information. Patent publication (CN1671901A) discloses a conductive thread, including at least one elastic core yarn, at least one conductive thread wound around the core yarn, and a non-conductive binding thread. The elasticity of the entire conductive thread is limited by the binding thread, and the wound conductive thread uses relatively fine metal wire. Patent publication (CN107700010A) discloses the preparation of a smart conductive yarn by depositing metal nanoparticles on the surface of elastic core-spun yarn using magnetron sputtering; stretching and elongating the core-spun yarn causes the metal nanoparticles to rearrange and recombine, thereby causing a change in the resistivity of the conductive yarn. The principle of the above conductive yarns is that the deformation of the conductive yarn causes a change in the yarn's resistance, thus reflecting the relevant physiological activity state of the human body. However, their preparation process is complex and costly. Summary of the Invention

[0004] The purpose of this invention is to address the problems of existing conductive yarns used in flexible sensors by providing a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure and its preparation method.

[0005] To achieve the above objectives, according to one aspect of the present invention, the present invention adopts the following technical solution:

[0006] A method for preparing a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure is characterized by: firstly, preparing an insulating electrospun nanofiber membrane and cutting it into long strips, then spirally wrapping the membrane onto the surface of a conductive core yarn to prepare a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure. Under axial tensile load, this intelligent conductive composite yarn exhibits a negative Poisson's ratio effect, enabling the surface electrospun nanofiber membrane to switch from a sheet-like to a linear form, while the internal conductive core yarn switches to the surface of the composite yarn, achieving a conversion from insulation to conductivity.

[0007] As a preferred technical solution:

[0008] The electrospun nanofiber membrane being coated is an insulating nanofiber membrane, including but not limited to polyvinylidene fluoride nanofiber membrane, polyamide-imide nanofiber membrane, and polytetrafluoroethylene nanofiber membrane.

[0009] Core yarns include, but are not limited to, silver-plated polyester covered yarn and silver-plated nylon covered yarn.

[0010] The coating electrospun nanofiber membrane has a thickness of 50~200μm, an elastic elongation of 30%~100%, and a tensile breaking strength of 5~50MPa.

[0011] The width of the elongated electrospun nanofiber membrane is 2mm to 7mm.

[0012] The core yarn inside the composite yarn has an elastic elongation rate of over 100%.

[0013] The coating rate of the electrospun nanofiber membrane on the surface of the composite yarn is 100%.

[0014] This invention also provides a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure, comprising an insulating electrospun nanofiber membrane, which is cut into strips and spirally wrapped around the surface of a conductive core yarn. The nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure is prepared using any of the preparation methods described above. Under axial tensile load, the nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure of this invention can achieve a surface electrospun nanofiber membrane switching from sheet-like to linear, while the internal conductive core yarn switches to the surface of the composite yarn, realizing a conversion from insulation to conductivity.

[0015] The present invention has the following beneficial effects:

[0016] (1) The present invention provides a nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure. Under axial tensile load, the surface electrospun nanofiber membrane can be switched from sheet to line, and the internal conductive core yarn can be switched to the surface of the composite yarn to achieve the conversion from insulation to conductivity.

[0017] (2) Existing flexible sensor conductive yarns usually reflect deformation through changes in yarn resistance. The intelligent conductive composite yarn of this invention realizes the switching between external insulating material and internal conductive core yarn through the negative Poisson's ratio effect, thereby realizing the conversion from insulation to conductivity, and thus reflecting deformation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the conductivity conversion properties of the nanofiber composite of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims. Example

[0020] A smart conductive composite yarn with a negative Poisson's ratio nanofiber structure and its preparation method are disclosed. First, an insulating polyvinylidene fluoride electrospun nanofiber membrane with a thickness of 150 μm, an elastic elongation of 50%, and a tensile breaking strength of 20 MPa is prepared and cut into strips with a width of 2 mm. Then, the nanofiber membrane is spirally wrapped with a 100% coverage rate onto the surface of a silver-plated polyester covered yarn with an elastic elongation of 110% to prepare a smart conductive composite yarn with a negative Poisson's ratio structure.

[0021] Reference Figure 1 The resulting nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure has a fully covered sheet-like insulating nanofiber membrane on its surface in its natural state. Under axial tensile load, the composite yarn can switch the surface insulating polyvinylidene fluoride electrospun nanofiber membrane from sheet to line, while the internal silver-plated polyester covering yarn switches to the surface of the composite yarn to achieve the conversion from insulation to conductivity. Example

[0022] A smart conductive composite yarn with a negative Poisson's ratio nanofiber structure and its preparation method are disclosed. First, an insulating polytetrafluoroethylene electrospun nanofiber membrane with a thickness of 200 μm, an elastic elongation of 30%, and a tensile breaking strength of 30 MPa is prepared and cut into strips with a width of 5 mm. Then, the nanofiber membrane is spirally wrapped with silver-plated polyester covering yarn with an elastic elongation of 110% to prepare a smart conductive composite yarn with a negative Poisson's ratio structure.

[0023] Reference Figure 1 The resulting nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure has a fully covered sheet-like insulating nanofiber membrane on its surface in its natural state. Under axial tensile load, the composite yarn can switch the surface insulating polytetrafluoroethylene electrospun nanofiber membrane from sheet to thread, while the internal silver-plated polyester covering yarn switches to the surface of the composite yarn to achieve the conversion from insulation to conductivity. Example

[0024] A smart conductive composite yarn with a negative Poisson's ratio structure and its preparation method are disclosed. First, an insulating polyamide-imide electrospun nanofiber membrane with a thickness of 150 μm, an elastic elongation of 50%, and a tensile breaking strength of 50 MPa is prepared and cut into strips with a width of 7 mm. Then, the strips are spirally wrapped with the nanofiber membrane at a 100% coverage rate onto the surface of a silver-plated nylon coated yarn with an elastic elongation of 130% to prepare a smart conductive composite yarn with a negative Poisson's ratio structure.

[0025] Reference Figure 1 The resulting nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure has a fully covered sheet-like insulating nanofiber membrane on its surface in its natural state. Under axial tensile load, the composite yarn can switch the surface insulating polyamide-imide electrospun nanofiber membrane from sheet to thread, while the internal silver-plated nylon covering yarn switches to the surface of the composite yarn to achieve the conversion from insulation to conductivity. Example

[0026] A smart conductive composite yarn with a negative Poisson's ratio structure and its preparation method are disclosed. First, an insulating polyvinylidene fluoride electrospun nanofiber membrane with a thickness of 50 μm, an elastic elongation of 45%, and a tensile breaking strength of 15 MPa is prepared and cut into strips with a width of 3 mm. Then, the nanofiber membrane is spirally wrapped with a silver-plated polyester covering yarn with an elastic elongation of 110% to prepare a smart conductive composite yarn with a negative Poisson's ratio structure.

[0027] Reference Figure 1 The resulting nanofiber intelligent conductive composite yarn with a negative Poisson's ratio structure has a fully covered sheet-like insulating nanofiber membrane on its surface in its natural state. Under axial tensile load, the composite yarn can switch the surface insulating polyvinylidene fluoride electrospun nanofiber membrane from sheet to line, while the internal silver-plated polyester covering yarn switches to the surface of the composite yarn to achieve the conversion from insulation to conductivity.

Claims

1. A method for preparing a conductive composite yarn of nanofibers with a negative Poisson's ratio structure, characterized in that: First, an insulating electrospun nanofiber membrane is prepared and cut into long strips. Then, it is spirally wrapped onto the surface of a conductive core yarn to prepare a nanofiber conductive composite yarn with a negative Poisson's ratio structure. The elastic elongation of the nanofiber membrane is 30%~50%, and the tensile breaking strength of the nanofiber membrane is 5~50MPa; the elastic elongation of the conductive core yarn is higher than 100%.

2. The method for preparing a nanofiber conductive composite yarn with a negative Poisson's ratio structure according to claim 1, characterized in that... The range of insulating nanofiber membranes includes polyvinylidene fluoride nanofiber membranes, polyamide-imide nanofiber membranes, and polytetrafluoroethylene nanofiber membranes.

3. The method for preparing a nanofiber conductive composite yarn with a negative Poisson's ratio structure according to claim 1, characterized in that... The thickness of the electrospun nanofiber membrane is 50~200μm.

4. The method for preparing a conductive composite yarn with a negative Poisson's ratio nanofiber structure according to claim 1, characterized in that... The width of the elongated electrospun nanofiber membrane is 2mm to 7mm.

5. The method for preparing a nanofiber conductive composite yarn with a negative Poisson's ratio structure according to claim 1, characterized in that... Its internal core yarn is a conductive yarn, and the selection range includes silver-plated polyester covered yarn and silver-plated nylon covered yarn.

6. The method for preparing a nanofiber conductive composite yarn with a negative Poisson's ratio structure according to claim 1, characterized in that... The coating rate of the electrospun nanofiber membrane on the surface of the composite yarn is 100%.

7. The method for preparing a nanofiber conductive composite yarn with a negative Poisson's ratio structure according to claim 1, characterized in that... Under axial tensile load, composite yarn with negative Poisson's ratio structure can realize the surface electrospun nanofiber membrane switching from sheet to line, while the internal conductive core yarn switches to the surface of the composite yarn to realize the conversion from insulation to conductivity.

8. A nanofiber conductive composite yarn with a negative Poisson's ratio structure, characterized in that... This includes an insulating electrospun nanofiber membrane, which is cut into long strips and spirally wrapped around the surface of a conductive core yarn; the elastic elongation of the nanofiber membrane is 30%~100%, and the tensile breaking strength of the nanofiber membrane is 5~50MPa; the elastic elongation of the conductive core yarn is higher than 100%.

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