Anti-interference nanofiber yarn pressure sensing fabric and preparation method thereof

Abstract

The present invention discloses an interference-resistant nanofiber yarn pressure sensing fabric and a preparation method thereof, belonging to the field of wearable sensing textile technology. The interference-resistant nanofiber yarn pressure sensing fabric comprises: an upper fabric group and a lower fabric group knitted from nanofiber yarn using a knitting machine; wherein the conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group serve as electrode layers; and the lower shell layer of the upper fabric group, the upper shell layer of the lower fabric group, and an air layer constitute a dielectric layer. The present invention provides a solution to the problems of the prior art, such as the complex preparation process of tensile interference-resistant flexible mechanical sensors, the low sensitivity of compressive strain sensing materials, and the severe interference of tensile strain signals.

Description

Technical Field

[0001] This invention relates to the field of wearable sensing textile technology, and more specifically to an anti-interference nanofiber yarn pressure sensing fabric and its preparation method. Background Technology

[0002] With the rapid development of the Internet of Things, artificial intelligence, and flexible electronics, sensors, as one of the key sensing elements, have gradually entered people's lives and attracted widespread attention from researchers. Sensors play a fundamental and crucial role in modern smart textile technology. Among them, fabric-based sensors have attracted much attention from scholars due to their flexibility and tensile strength. In the past few decades, flexible fabric-based sensors have made remarkable progress in electronic skin, human motion, health monitoring, and human-computer interaction. Compared with traditional rigid sensors, flexible sensors have the advantages of bendable and deformable substrates, enabling their application in wearable devices. Among them, capacitive fabric-based flexible pressure sensors are widely used due to their simple structure, high sensitivity, low cost, low power consumption, low noise level, and long-term stability. However, achieving low-cost manufacturing of capacitive fabric-based flexible pressure sensors with high resolution, high sensitivity, rapid response, and the ability to detect complex signals remains a difficult challenge.

[0003] Furthermore, current flexible mechanical sensors are often limited to responding to single stimuli. However, most sensing signals in reality are triggered by coupling forces, such as a combination of tension and pressure. Due to the mutual interference between tension and pressure, tension is difficult to decouple or eliminate from the coupling force. Pressure sensors will be unable to accurately monitor and assess specific human movements because tension is difficult to decouple or eliminate from the coupling force. Therefore, improving the sensing accuracy under the action of coupling forces has become one of the key challenges in practical applications.

[0004] Electrospun nanofibers combine the advantages of both nanomaterials and fiber materials, possessing excellent properties such as extremely fine size, large specific surface area, controllable structure, and easy doping and functional modification. They have been widely used as an ideal material in smart wearable fields such as flexible sensors, electronic skin, optoelectronic devices, and energy harvesting and storage.

[0005] Therefore, how to provide an interference-resistant nanofiber yarn pressure sensing fabric and its preparation method is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides an interference-resistant nanofiber yarn pressure-sensing fabric and its preparation method. First, a highly sensitive nanofiber yarn is prepared using conjugate electrospinning technology, and then a flexible pressure-sensing fabric is further constructed based on this yarn. This addresses the problems of complex fabrication processes, low sensitivity of compressive strain sensing materials, and severe interference with tensile strain signals in current tensile interference-resistant flexible mechanical sensors, enabling accurate monitoring and evaluation under specific complex human motion conditions. This pressure-sensing fabric has potential applications in human motion recognition and physiological health monitoring.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An interference-resistant nanofiber yarn pressure-sensing fabric, comprising:

[0009] The upper and lower fabric layers are woven from nanofiber yarns using a knitting machine.

[0010] The conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group are used as electrode layers.

[0011] The lower shell of the upper fabric group, the upper shell of the lower fabric group, and the air layer constitute a dielectric layer.

[0012] Preferably, the conductive core layer is made of conductive spandex.

[0013] Preferably, the upper shell and the lower shell are both conductive composite nanofiber materials.

[0014] A method for preparing an interference-resistant nanofiber yarn pressure-sensing fabric, comprising:

[0015] S100: The prepared solution is loaded into the nanofiber yarn preparation device to obtain nanofiber yarn;

[0016] S200: The nanofiber yarn is knitted into two fabric groups (upper fabric group and lower fabric group) using a knitting machine;

[0017] S300: Two fabric groups (upper fabric group and lower fabric group) are assembled into an interference-resistant nanofiber yarn pressure sensing fabric.

[0018] Preferably, the nanofiber yarn preparation apparatus includes:

[0019] Syringe, syringe pump, copper funnel, left needle, right needle, collector, high-voltage power supply;

[0020] The prepared solution is loaded into two syringes, which are connected to two injection pumps. The two syringes are arranged opposite each other on the copper funnel. The distance between the tip of the left needle and the tip of the right needle and the collector is 14-16 cm, and the angle between the left needle and the right needle and the copper funnel is 30°. Two high-voltage power supplies are connected to the tips of the left needle and the right needle using alligator clips, so that one of the left needles is positively charged and the other is negatively charged. In addition, the copper funnel is connected to the ground wire through the alligator clips. Conductive spandex yarn is passed through the copper funnel. During the electrospinning process, the fibers are collected on the surface of the copper funnel and twisted and wound onto the yarn to obtain nanofiber yarn.

[0021] Preferably, the syringe pump is set to a rate of 3 mL / h and a voltage range of 8-10 kV.

[0022] Preferably, the interference-resistant nanofiber yarn pressure sensing fabric has a resolution of 0.1 N and a detection limit of 0.17 Pa.

[0023] As can be seen from the above technical solution, compared with the prior art, this invention discloses an anti-interference nanofiber yarn pressure sensing fabric and its preparation method, which has high sensitivity, wide detection range, and tensile strain resistance. This flexible pressure sensing fabric has potential applications in human motion recognition and physiological health monitoring. It provides new ideas and approaches for the development of intelligent wearable textiles, enhances my country's technological competitiveness in the digital sports and health medical industry, and has significant scientific significance and research value. Specific beneficial effects are as follows:

[0024] (1) This invention utilizes simple conjugate electrospinning to obtain highly sensitive sensing yarns with nanostructures. Subsequently, the prepared nanofiber yarns or nanofiber core-spun yarns are further processed into fabrics using a textile machine, thereby integrating electrospun nanofibers into everyday textiles. The entire preparation process is simple and easy to operate, the principle is reliable, the process is simple, the cost is low, the energy consumption is low, and it is environmentally friendly.

[0025] (2) The flexible sensing fabric made of nanofiber yarn prepared by the present invention has the ability to have high sensitivity, wide detection range and tensile strain resistance. Due to the microstructure of the nanofiber yarn shell, the resolution of the flexible sensing fabric is as low as 0.1N and the detection limit is 0.17Pa, which exceeds the performance of most existing flexible sensors.

[0026] (3) The flexible sensing fabric of nanofiber yarn prepared by the present invention can be used in human body monitoring systems, including signals such as human finger bending, wrist bending, knee bending, running, squatting and standing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 A schematic diagram of the anti-interference nanofiber yarn pressure sensing fabric structure provided by the present invention.

[0029] Figure 2 The energy spectrum of the nanofiber yarn provided in Embodiment 2 of the present invention;

[0030] Figure 3 The images show electron microscope comparisons of different nanofiber yarn cross-sections provided in Example 2 of this invention.

[0031] Figure 4 This is a schematic diagram of the sensing performance test results provided in Embodiment 5 of the present invention;

[0032] Figure 5 This is a schematic diagram of the pressure sensing resolution test results provided in Embodiment 6 of the present invention;

[0033] Figure 6 This is a schematic diagram of the pressure sensing detection lower limit test results provided in Embodiment 7 of the present invention;

[0034] Figure 7 This is a diagram illustrating the tensile strength of the fabric under pressure, provided in Embodiment 8 of the present invention.

[0035] Figure 8 This is a schematic diagram of the human motion detection and recognition results provided in Embodiment 9 of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The purpose of this invention is to provide an anti-interference nanofiber yarn pressure sensing fabric and its preparation method. This anti-interference nanofiber yarn pressure sensing fabric comprises: an upper fabric group and a lower fabric group woven from nanofiber yarn using a knitting machine; wherein, the conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group serve as electrode layers; the lower shell layer of the upper fabric group, the upper shell layer of the lower fabric group, and an air layer constitute a dielectric layer. This invention provides a solution to the problems of complex fabrication process, low sensitivity of compressive strain sensing materials, and severe interference of tensile strain signals in existing technologies for anti-tensile interference flexible mechanical sensors.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] See Figure 1 Embodiment 1 of the present invention discloses an interference-resistant nanofiber yarn pressure sensing fabric, comprising:

[0041] The upper and lower fabric layers are woven from nanofiber yarns using a knitting machine.

[0042] Among them, the conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group are used as electrode layers;

[0043] The dielectric layer consists of the lower shell of the upper fabric group, the upper shell of the lower fabric group, and the air layer.

[0044] Traditional capacitive sensors have a classic three-layer structure, consisting of upper and lower electrode layers and a middle dielectric layer. In this patent, unlike the traditional approach, Embodiment 1 constructs a pressure sensor based on capacitive sensing, consisting of two layers of fabric. This is a novel double-shell core interwoven structure, where the lower shell layer of the upper fabric and the upper shell layer of the lower fabric, along with an air layer, together form the dielectric layer. Two parallel or twisted yarns constitute the capacitor.

[0045] In one specific embodiment, the material of the conductive core layer is conductive spandex.

[0046] In one specific embodiment, the upper shell and the lower shell are both conductive composite nanofiber materials.

[0047] Example 2

[0048] The method for preparing the interference-resistant nanofiber yarn pressure-sensing fabric in this embodiment is as follows:

[0049] The prepared spinning solution was loaded into two 10ml syringes. The spinning solution formula was: 5g thermoplastic polyurethane (TPU) granules; 10g N,N-dimethylformamide (DMF) solvent; and 10g tetrahydrofuran (THF) solvent.

[0050] All syringe pumps were set to a rate of 3 mL / h, and the voltage was set between 8 and 10 kV.

[0051] The syringes are arranged symmetrically on the copper funnel, with the distance between the left and right needle tips and the collector being 14-16 cm. The angle between each needle tip and the funnel is 30°.

[0052] Two high-voltage power sources are connected to the needle tip using alligator clips; one needle tip is positively charged, and the other is negatively charged.

[0053] Specifically, two high-voltage power supplies control the voltages of the positive and negative electrodes, respectively. Normally, conjugated electrospinning requires two charged polymer jets with opposite polarities to simultaneously break through the Taylor cone and converge at the center to form nanofiber yarns. Therefore, two power supplies are needed, with different polarities but often the same numerical value.

[0054] The copper funnel is connected by connecting electrodes to copper wires wound around the bottom of the funnel. The funnel is grounded, and conductive spandex yarn is passed through the funnel and placed at the geometric center. During electrospinning, the fibers are collected on the surface of the copper funnel and twisted and wound onto the yarn.

[0055] Specifically, such as Figure 2 The energy dispersive spectroscopy (EDS) spectrum of the nanofiber yarn reveals the coexistence of C, O, N, and Ag in the sample, with no other impurities. Furthermore, Ag is only present in the core layer of the yarn, which strongly suggests that the nanofibers gradually wrap around and twist onto the core layer during conjugated electrospinning, forming a classic core-shell structure.

[0056] Using a knitting machine, nanofiber yarns are woven into a highly sensitive pressure-sensing fabric.

[0057] Two highly sensitive pressure-sensing fabrics were assembled into an interference-resistant nanofiber yarn pressure-sensing fabric.

[0058] The microstructure of the obtained anti-interference nanofiber yarn pressure sensing fabric was observed using a JEM-7500F scanning electron microscope. Under the conditions of accelerating voltage of 5kV and current of 10μA, a clear surface morphology image was obtained by adjusting the lens magnification.

[0059] See Figure 3The figures show electron micrographs of cross-sections of nanofiber yarns with different shell thicknesses prepared under different spinning conditions. Samples 1, 2, and 3 exhibit distinct core-shell structures, with the core being conductive yarn and the shell being TPU nanofibers coated and twisted. See Table 1 for details: Sample 1: 3 mL / h spinning speed, 10 kV voltage, 2 rpm winding speed, 20 rpm roller speed; Sample 2: 3 mL / h spinning speed, 10 kV voltage, 5 rpm winding speed, 40 rpm roller speed; Sample 3: 3 mL / h spinning speed, 10 kV voltage, 10 rpm winding speed, 60 rpm roller speed. It can be seen that the different shell thicknesses are mainly adjusted by matching the spinning winding speed (1–20 rpm) and roller speed (20–100 rpm).

[0060] Table 1. Sample fiber thickness

[0061]

[0062] Example 3

[0063] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0064] The elemental distribution of the test yarn cross section of the obtained anti-interference nanofiber yarn pressure sensing fabric was characterized by EDS, as shown in Table 2.

[0065] Table 2 Element Distribution Table

[0066]

[0067]

[0068] The elemental distribution table fully illustrates the core-shell structure of the nanofiber core-spun yarn of the present invention, and the Ag element is only in the core layer, which is consistent with the nanofiber yarn pressure sensing fabric structure design of the present invention. It is based on this design that it has excellent sensing capabilities.

[0069] Example 4

[0070] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0071] The hydrophilicity and hydrophobicity of the obtained anti-interference nanofiber yarn pressure sensing fabric were tested using a water contact angle tester. As shown in Table 3, the anti-interference nanofiber yarn pressure sensing fabric is hydrophobic in the water contact angle test. Good hydrophobicity can ensure that sweat or rainwater does not affect the sensor when the human body wears it, thereby increasing the service life and stability of the sensing fabric.

[0072] Table 3 Water Contact Angle Test Table

[0073]

[0074] Example 5

[0075] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0076] The obtained anti-interference nanofiber yarn pressure-sensing fabric was subjected to pressure sensing tests to determine its sensitivity and sensing range. (See [reference needed]). Figure 4 As shown, in the sensing performance test, the rate of change of sensor capacitance (ΔC / C) increases with increasing applied pressure, exhibiting remarkable sensitivity at low pressures (65.3 kPa). -1 It has an extremely wide sensing range (up to 700 kPa), exceeding the performance of most existing flexible sensors.

[0077] Example 6

[0078] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0079] The obtained anti-interference nanofiber yarn pressure-sensing fabric was subjected to pressure-sensing tests, such as... Figure 5 As shown, the anti-interference nanofiber yarn pressure sensing fabric has a sensing resolution as low as 0.1N. Applying different pressures to the anti-interference nanofiber yarn pressure sensing fabric will result in different steps, and the steps are stable without obvious fluctuations, indicating the signal stability of the anti-interference nanofiber yarn pressure sensing fabric.

[0080] Example 7

[0081] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0082] The obtained anti-interference nanofiber yarn pressure-sensing fabric was subjected to pressure-sensing tests, see [link to relevant documentation]. Figure 6 As shown, the detection limit is extremely low, reaching 0.17 Pa, exceeding the performance of most existing flexible sensors.

[0083] Example 8

[0084] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0085] The obtained anti-interference nanofiber yarn pressure sensing fabric was subjected to tensile strength testing, and its anti-interference performance was tested under the condition of a heavy object being loaded. Figure 7 As shown, the fabric exhibits tensile strength under pressure, with the electrical signal changing by only 3% at 100% tensile strain.

[0086] Example 9

[0087] The preparation of the anti-interference nanofiber yarn pressure sensing fabric in this embodiment is the same as in Embodiment 2.

[0088] The obtained anti-interference nanofiber yarn pressure-sensing fabric was used for human motion detection and recognition, including signals such as finger bending, wrist bending, knee bending, running, and squatting. Figure 8 It can be seen that from minute movements such as pulse and swallowing to large movements such as running and squatting, this interference-resistant nanofiber yarn pressure sensing fabric can detect human movements across the entire range, and has good application potential in the field of smart wearables.

[0089] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0090] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An anti-interference nanofiber yarn pressure sensing fabric, characterized in that, include: The upper and lower fabric layers are woven from nanofiber yarns using a knitting machine. The preparation method of nanofiber yarn is as follows: The nanofiber yarn has a core-shell structure, wherein the core layer is conductive spandex and the shell layer is TPU nanofiber. The TPU nanofiber is gradually wrapped and twisted onto the core layer in conjugated electrospinning to form the core-shell structure. The conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group are used as electrode layers. The lower shell of the upper fabric group, the upper shell of the lower fabric group, and the air layer constitute a dielectric layer; The conductive core layer of the upper fabric group and the conductive core layer of the lower fabric group are composed of core layers in nanofiber yarns, and the lower shell layer of the upper fabric group and the upper shell layer of the lower fabric group are composed of shell layers in nanofiber yarns.

2. The method for preparing an anti-interference nanofiber yarn pressure sensing fabric according to claim 1, characterized in that, include: S100: The prepared solution is loaded into the nanofiber yarn preparation device to obtain nanofiber yarn; S200: Using a knitting machine, the nanofiber yarn is knitted into an upper fabric group and a lower fabric group; S300: Assemble the upper and lower fabric layers into an interference-resistant nanofiber yarn pressure sensing fabric.

3. The method for preparing an anti-interference nanofiber yarn pressure sensing fabric according to claim 2, characterized in that, The nanofiber yarn preparation apparatus includes: Syringe, syringe pump, copper funnel, left needle, right needle, collector, high-voltage power supply; The prepared solution is loaded into two syringes, which are connected to two injection pumps. The two syringes are arranged opposite each other on a copper funnel. The distance between the tips of the left and right needles and the collector is 14-16 cm, and the angle between the left and right needles and the copper funnel is 30°. Two high-voltage power supplies are connected to the tips of the left and right needles using alligator clips, so that one of the left and right needles is positively charged and the other is negatively charged. The copper funnel is grounded. Conductive spandex yarn is passed through the copper funnel. During electrospinning, the fibers are collected on the surface of the copper funnel and twisted and wound onto the yarn to obtain nanofiber yarn. The prepared solution formulation is as follows: thermoplastic polyurethane (TPU) granules; N, N Dimethylformamide (DMF) solvent; tetrahydrofuran (THF) solvent.

4. The method for preparing an anti-interference nanofiber yarn pressure sensing fabric according to claim 3, characterized in that, The syringe pump is set to a rate of 3 mL / h and a voltage range of 8-10 kV.

5. The method for preparing an anti-interference nanofiber yarn pressure sensing fabric according to claim 3, characterized in that, The interference-resistant nanofiber yarn pressure sensing fabric has a resolution of 0.1 N and a detection limit of 0.17 Pa.

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