All-fiber color-changing unidirectional moisture-wicking triboelectric fabric, and preparation method and application thereof

Abstract

The application discloses a full-fiber color-changing one-way wet-conducting triboelectric fabric and a preparation method and application thereof, and belongs to the technical field of electrospun elastic fiber materials. The full-fiber one-way wet-conducting triboelectric fabric is composed of electrospun thermoplastic polyurethane / polyvinylidene fluoride-hexafluoropropylene nanofiber membranes (TPU / PVDF-HFP) as a hydrophobic layer, electrospun thermoplastic polyurethane / polyvinylidene fluoride-hexafluoropropylene / poloxamer F127 nanofiber membranes (TPU / PVDF-HFP / F127) as a super-hydrophilic layer, and liquid metal conductive paint (LM-Ag NPs) coated on the surface of the super-hydrophilic layer, so that the full-fiber one-way wet-conducting triboelectric fabric has the characteristics of rapid moisture absorption and sweat release, excellent mechanical properties and good conductivity. In addition, thermochromic microcapsules are added to the spinning solution of one or both of the hydrophobic layer and the super-hydrophilic layer to form a full-fiber color-changing one-way wet-conducting triboelectric fabric, so that the full-fiber color-changing one-way wet-conducting triboelectric fabric has temperature response and warning functions.

Description

Technical Field

[0001] This invention relates to a color-changing, one-way moisture-wicking triboelectric fabric, its preparation method, and its application, belonging to the technical field of electrospun elastic fiber materials. Background Technology

[0002] With the rapid development of society, economy, and technology, and the continuous improvement of living standards and demands, people's requirements for textiles are no longer limited to warmth and aesthetics; functional fabrics have emerged as a result. Flexible triboelectric fabrics, due to their mechanical flexibility, wearing comfort, and functional integration, have broad application prospects in fields such as energy harvesting and storage, intelligent sensing, soft robotics, and intelligent interconnection.

[0003] Currently, flexible triboelectric fabrics still suffer from poor electrical output performance and poor wearability (breathability and moisture permeability). For example, CN110138259A discloses a high-humidity resistant flexible wearable triboelectric nanogenerator, its preparation method, and its application. This triboelectric nanogenerator uses a polyhydroxy polymer rich in hydroxyl groups as the friction layer. The outer surface of the friction layer has raised micro / nano patterns. The hydroxyl groups readily form hydrogen bonds with water molecules, fixing water molecules from the environment to the material surface. The water molecules participate in triboelectric charging as a whole, increasing the total electrical output of the friction layer (17V, 2.7μA, 0.028W / m). 2 This allows it to be used in high humidity environments; however, it achieves surface micro-nano patterns through laser etching technology, which requires high-end equipment and has weak electrical output performance; at the same time, because it uses polymer film as the substrate and friction layer, it does not have moisture permeability and breathability during wear.

[0004] One-way moisture-wicking materials are typically prepared using multi-step methods to create composite materials with multi-layered structures, resulting in asymmetric wettability. For example, CN109972275B discloses a knitted fabric with one-way moisture wicking and its preparation method. The front side of the fabric is woven with hydrophilic yarn obtained through hydrophilic treatment to create a hydrophilic evaporation surface, while the reverse side is woven with Siro composite yarn to create a moisture-wicking surface. The Siro composite yarn contains equal amounts of hydrophilic and hydrophobic fibers, and the hydrophilic and hydrophobic points on the reverse side of the fabric can be evenly distributed, allowing sweat to be absorbed by the fabric and quickly wicked away to the front side, achieving a breathable and quick-drying effect. However, the lack of bonding between its multi-layered structure reduces its mechanical strength and shortens its service life; the preparation method is complex and costly.

[0005] Therefore, there is a need to seek flexible and stretchable friction and electrode materials to prepare a triboelectric fabric that combines mechanical flexibility with stable electrical output. Simultaneously, a one-step composite structure should be fabricated to achieve good breathability and moisture permeability during long-term wear. Summary of the Invention

[0006] [Technical Issues]

[0007] Existing flexible and stretchable materials are mostly dense polymer films, which result in poor wearing comfort for wearable devices.

[0008] Flexible materials exhibit weak interfacial bonding between conductive materials and the substrate during large tensile deformation, making it difficult to maintain stable electrical properties.

[0009] Wearable electronic devices are increasingly developing towards multifunctionality and intelligence. People who engage in strenuous exercise often generate a lot of heat, leading to an increase in body temperature; at this time, monitoring the body temperature of the exercising person is essential.

[0010] [Technical Solution]

[0011] To address the aforementioned issues, this invention utilizes an electrospun thermoplastic polyurethane / polyvinylidene fluoride-hexafluoropropylene nanofiber membrane (TPU / PVDF-HFP) as a hydrophobic layer and an electrospun thermoplastic polyurethane / polyvinylidene fluoride-hexafluoropropylene / poloxam F127 nanofiber membrane (TPU / PVDF-HFP / F127) as a superhydrophilic layer. Simultaneously, a liquid metal conductive coating (LM-Ag NPs) is coated onto the surface of the superhydrophilic layer, forming an all-fiber unidirectional moisture-wicking triboelectric fabric. This fabric possesses rapid moisture absorption and wicking properties, excellent mechanical properties, and good conductivity. Furthermore, thermochromic microcapsules are added to one or both layers of the spinning solution in the hydrophobic and superhydrophilic layers to form an all-fiber color-changing unidirectional moisture-wicking color-changing triboelectric fabric, endowing it with temperature response and warning functions.

[0012] The first objective of this invention is to provide a method for preparing an all-fiber unidirectional moisture-wicking triboelectric fabric, comprising the following steps:

[0013] (1) Preparation of spinning solution:

[0014] Thermoplastic polyurethane (TPU), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and organic solvent are mixed evenly to obtain TPU / PVDF-HFP spinning solution;

[0015] Add poloxamer F127 to the TPU / PVDF-HFP spinning solution and continue mixing until homogeneous to obtain the TPU / PVDF-HFP / F127 spinning solution.

[0016] (2) Preparation of all-fiber unidirectional moisture-wicking fabric:

[0017] The TPU / PVDF-HFP spinning solution was electrospun to form the first layer of nanofiber fabric as a hydrophobic layer; then, using the first layer of nanofiber fabric as a substrate, the TPU / PVDF-HFP / F127 spinning solution was electrospun onto the first layer of nanofiber fabric as a superhydrophilic layer. After drying and solvent evaporation, an all-fiber unidirectional moisture-wicking fabric was obtained.

[0018] (3) Preparation of all-fiber unidirectional moisture-wicking triboelectric fabric:

[0019] LM-Ag NPs conductive coating was coated on the superhydrophilic layer surface of an all-fiber unidirectional moisture-wicking fabric. After drying and solvent evaporation, an all-fiber unidirectional moisture-wicking triboelectric fabric was obtained.

[0020] In one embodiment of the present invention, the mass ratio of TPU:PVDF-HFP:organic solvent in step (1) is 1-5g:0.5-3g:10g.

[0021] In one embodiment of the present invention, the mass ratio of the TPU / PVDF-HFP blend system (the sum of the masses of TPU, PVDF-HFP and solvent) to poloxamer F127 in step (1) is 10:0.1-0.3.

[0022] In one embodiment of the present invention, the organic solvent in step (1) is a mixture of N,N-dimethylformamide and tetrahydrofuran, with a volume ratio of 100:0 to 60:40, but not 0.

[0023] In one embodiment of the present invention, the uniform mixing in step (1) is carried out at 45-55°C and 300-500 rpm for 2-4 hours.

[0024] In one embodiment of the present invention, the mixing in step (1) is continued at 45-55°C and 300-500 rpm for 2-4 hours.

[0025] In one embodiment of the present invention, the parameters for electrospinning in step (2) are:

[0026] The voltage is 12-25V, the injection rate is 0.2-10mL / h, the needle diameter is 0.2-1mm, the receiving distance is 10-30cm, the receiving roller speed is 60-240rpm, the ambient temperature is 25-40℃, and the relative humidity is 15-60%.

[0027] In one embodiment of the present invention, the thickness of the superhydrophilic layer in step (2) is 30-300 μm, and the thickness ratio of the superhydrophilic layer to the hydrophobic layer is 1:0.5-0.9.

[0028] In one embodiment of the present invention, in step (2), the superhydrophilic layer has a small pore size and the hydrophobic layer has a large pore size.

[0029] In one embodiment of the present invention, the preparation method of the LM-Ag NPs conductive coating in step (3) is as follows:

[0030] Liquid metal (LM) and toluene were mixed and ultrasonically treated to obtain a liquid metal nanoparticle dispersion; then, the liquid metal nanoparticle dispersion was mixed with silver nanosheets (AgNPs) and ultrasonically treated again to obtain an LM-Ag NPs conductive coating.

[0031] Among them, liquid metal LM is one or more of the following: eutectic gallium indium alloy EGaIn, gallium indium tin alloy, pure bismuth, bismuth indium tin alloy, and pure gallium.

[0032] The ratio of liquid metal LM, toluene, and silver nanosheets Ag NPs is 0.5-2g: 6mL: 0.1-0.4g;

[0033] The ultrasonic treatment conditions are 300-350W ultrasonic treatment for 0.5-6 hours;

[0034] Continue with ultrasonic treatment at 300-350W for 10-30 minutes.

[0035] In one embodiment of the present invention, the coating amount of LM-Ag NPs conductive coating in step (3) is 0.1-6 mg / cm³. 2 .

[0036] The second objective of this invention is to obtain a full-fiber unidirectional moisture-wicking triboelectric fabric prepared by the method described in this invention.

[0037] In one embodiment of the present invention, the thickness of the all-fiber unidirectional moisture-wicking triboelectric fabric is 90-600 μm.

[0038] The third objective of this invention is to provide a method for preparing a full-fiber color-changing unidirectional moisture-wicking triboelectric fabric, wherein the method involves adding thermochromic microcapsules during the preparation of the full-fiber unidirectional moisture-wicking triboelectric fabric.

[0039] In one embodiment of the present invention, the thermochromic microcapsules are added to one or both of the TPU / PVDF-HFP spinning solution and the TPU / PVDF-HFP / F127 spinning solution, and the concentration of the thermochromic microcapsules in the spinning solution is 1-20 wt%.

[0040] The fourth objective of this invention is to obtain a full-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared by the method described in this invention.

[0041] In one embodiment of the present invention, the thickness of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric is 90-600 μm.

[0042] The fifth objective of this invention is the application of the all-fiber unidirectional moisture-wicking triboelectric fabric and the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric described herein in flexible electrodes, wearable electronic devices, and smart textiles.

[0043] The sixth objective of this invention is to provide a triboelectric generator, which uses the all-fiber unidirectional moisture-wicking triboelectric fabric or all-fiber color-changing unidirectional moisture-wicking triboelectric fabric described in this invention as the electrode and negative friction material, and aluminum foil as the positive electrode and positive friction material. The positive and negative electrodes are connected together, and mechanical energy is converted into electrical energy through triboelectric power generation, thus forming a generator.

[0044] The seventh objective of this invention is to provide a wearable electronic fabric that employs the all-fiber unidirectional moisture-wicking triboelectric fabric or the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric described in this invention.

[0045] [Beneficial Effects]

[0046] (1) The gradient pore structure prepared by the one-step electrospinning method in this invention is simple to prepare and has a short process flow; the fiber pore size and diameter, fabric thickness and other parameters can be effectively controlled by the spinning process parameters.

[0047] (2) The silver nanosheets used in the unidirectional moisture-conducting triboelectric fabric of the present invention can significantly reduce the surface tension of liquid metal, so that the LM-Ag NPs conductive coating and the nanofiber fabric can achieve a stable interface bond, which is not easy to fall off, has excellent electrical properties, high robustness, and a long service life.

[0048] (3) The thickness of the LM-AgNPs conductive coating is controllable, giving it both excellent conductivity and unidirectional moisture-wicking effect.

[0049] (4) The all-fiber color-changing unidirectional moisture-wicking triboelectric fabric of the present invention consists of a macroporous elastic hydrophobic layer, a microporous elastic superhydrophilic layer, and an LM-Ag NPs electrode layer from the outside to the inside; the gradient structure of the electrospun electronegative material PVDF-HFP and the polymer elastomer TPU endows the fabric with unidirectional moisture-wicking properties, and has excellent stretchability and electrical output characteristics.

[0050] (5) The present invention introduces thermochromic microcapsules, which are used for real-time monitoring of changes in human body temperature, reminding people to cool down in time when their body temperature is too high, and realizing the temperature visualization function of wearable electronic fabrics.

[0051] (6) The all-fiber color-changing unidirectional moisture-wicking triboelectric fabric of the present invention combines unidirectional moisture wicking and triboelectric fabric, and has broad application prospects in the fields of flexible electrodes, wearable electronic devices, and smart textiles. Attached Figure Description

[0052] Figure 1 This is a structural diagram of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared according to the present invention.

[0053] Figure 2 Scanning electron microscope images of the hydrophobic layer (a) and superhydrophilic layer (b) in the all-fiber unidirectional moisture-wicking fabric prepared in Example 1.

[0054] Figure 3 This is a schematic diagram showing the dynamic changes in the water contact angle of TPH (TPU / PVDF-HFP fabric), TPH / F-127 (TPU / PVDF-HFP / F127 fabric), and the all-fiber unidirectional moisture-conducting triboelectric fabric (LM-Ag NPs / Bilayered e-textile) prepared in Example 1.

[0055] Figure 4 This is a schematic diagram of the operation of the all-fiber unidirectional moisture-wicking triboelectric fabric prepared in Example 1; wherein the triboelectric layer is in (i) complete contact (compression); (ii) separation (release); iii complete separation (release); (iv) contact (compression).

[0056] Figure 5 The diagram shows the electrical output signal of the all-fiber unidirectional moisture-wicking triboelectric fabric prepared in Example 1; where (a) is the open-circuit voltage and (b) is the short-circuit current.

[0057] Figure 6 Stress-strain curves of TPH (TPU / PVDF-HFP fabric), TPH / F-127 (TPU / PVDF-HFP / F127 fabric), the all-fiber unidirectional moisture-conducting triboelectric fabric (LM-Ag NPs / Bilayered e-textile) prepared in Example 1, and the all-fiber color-changing unidirectional moisture-conducting triboelectric fabric (LM-AgNPs / Bilayered e-textile@TMs) prepared in Example 3.

[0058] Figure 7 The image shows a scanning electron microscope image of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3.

[0059] Figure 8 The electrothermal temperature response results are for the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3.

[0060] Figure 9This demonstrates the temperature response stability of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3. Detailed Implementation

[0061] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0062] Test method:

[0063] 1. Contact angle test:

[0064] The fabric exhibits hydrophobicity and superhydrophilicity on both sides.

[0065] Using a contact angle tester, a 5μL drop of water was dropped onto the bottom layer, top layer, and middle layer of the fabric, and the change in the contact angle of the water drop was measured.

[0066] 2. Mechanical property testing:

[0067] Nanofiber fabrics were cut into 30mm×10mm strips, clamped in an electronic universal testing machine with a spacing of 20mm, and the breaking strength and elongation at break of different nanofiber fabrics were tested.

[0068] 3. Temperature alarm test:

[0069] The color-changing unidirectional moisture-wicking triboelectric fabric was placed on a heating stage, and the color change of the fiber membrane at different temperatures was tested.

[0070] 4. One-way moisture conduction test:

[0071] The moisture transfer performance of the fabric was tested using a moisture management tester. A 0.15M sodium chloride aqueous solution was added to the hydrophobic layer, and the moisture transfer was monitored by a sensor to obtain the liquid water unidirectional transfer index of the fabric.

[0072] 5. Triboelectric properties (open circuit voltage, short circuit current) test:

[0073] The all-fiber unidirectional moisture-conducting triboelectric fabric was cut to 8×9cm. 2 In the sample, the all-fiber unidirectional moisture-wicking triboelectric fabric is conducted to the external circuit through copper wires. Through repeated contact-separation processes, an alternating current signal (open-circuit voltage V) is generated in the external circuit. oc and short-circuit current I sc By integrating it into circuits, mechanical energy conversion and the driving of small electronic devices can be achieved.

[0074] Raw materials used in the examples and comparative examples:

[0075] Thermoplastic polyurethane (TPU): Granules; Model: 1181A; Purchased from Shanghai Vita Biotechnology Co., Ltd.

[0076] Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer: powder, M w 400,000; purchased from Shanghai Aijie Biotechnology Co., Ltd.

[0077] Poloxamer F127: Purchased from Aladdin Biochemical Technology Co., Ltd.;

[0078] Thermochromic microcapsules: thermochromic temperatures of 33℃ and 35℃; purchased from Shenzhen Oriental Color Changing Technology Co., Ltd.

[0079] Eutectic gallium-indium alloy EGaIn: Melting point: 16℃; purchased from Dongguan Dingguan Metal Technology Co., Ltd.

[0080] Silver nanosheets (AgNPs): sheet diameter 1–5 μm; purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd.

[0081] The structure of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared by this invention is as follows: Figure 1 :

[0082] The structure of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric is a sandwich structure, namely a hydrophobic surface layer, a superhydrophilic middle layer, and a liquid metal conductive layer. The liquid metal conductive layer is used as the electrode, the hydrophobic layer is used as the negative friction layer, and the aluminum foil is used as the positive friction layer and the other side electrode. It is connected to other conductors through copper wires. When the triboelectric fabric rubs against and contacts and separates from different materials, it can output an electrical signal in the liquid metal conductive layer.

[0083] Example 1

[0084] A method for preparing an all-fiber unidirectional moisture-wicking triboelectric fabric includes the following steps:

[0085] (1) Preparation of spinning solution:

[0086] 1.05g of thermoplastic polyurethane (TPU) granules, 0.45g of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer powder, and 8.5g of tetrahydrofuran (THF) and N'N-dimethylformamide (DMF) mixed solvent (THF to DMF volume ratio of 3:1) were stirred at 50℃ and 500rpm in an oil bath for 12 hours to prepare a TPU / PVDF-HFP spinning solution with a concentration of 15wt%.

[0087] Add 0.3g of poloxamer F127 to 10g of TPU / PVDF-HFP spinning solution, and stir at a constant temperature of 50℃ and 500rpm for 3h to mix evenly to obtain spinning solution TPU / PVDF-HFP / F127.

[0088] (2) Preparation of all-fiber unidirectional moisture-wicking fabric:

[0089] The TPU / PVDF-HFP spinning solution was electrospun (spinning voltage 22kV, spinneret orifice size 22G, injection speed 10mL / h, roller speed 170rpm, receiving distance 12cm, ambient temperature 25℃, relative humidity 40%) to form the first layer of nanofiber fabric as a superhydrophilic layer with a thickness of 100μm.

[0090] The TPU / PVDF-HFP / F127 spinning solution was then electrospun (spinning voltage 16kV, spinneret orifice size 22G, injection speed 1mL / h, roller speed 170rpm, receiving distance 12cm, ambient temperature 25℃, relative humidity 40%) and deposited onto the first layer of nanofiber fabric to form a hydrophobic layer (thickness 90μm). After drying, a full-fiber unidirectional moisture-wicking fabric (thickness approximately 200μm) was obtained.

[0091] (3) Preparation of all-fiber unidirectional moisture-wicking triboelectric fabric:

[0092] 1.5g of EGaIn was weighed and added to 6mL of toluene. The mixture was sonicated at 320W for 1h to obtain a liquid metal nanoparticle dispersion. Subsequently, 0.3g of Ag NPs was introduced into the dispersion and sonicated at 320W for 10min to obtain a uniform and stable LM-Ag NPs conductive coating.

[0093] The LM-Ag NPs conductive coating was uniformly coated onto the surface of the superhydrophilic layer of the all-fiber unidirectional moisture-wicking fabric, with a coating amount of 4 mg / cm². 2 After the solvent evaporates at room temperature for 2 hours, a full-fiber unidirectional moisture-wicking triboelectric fabric is obtained.

[0094] The obtained all-fiber unidirectional moisture-wicking fabric and all-fiber unidirectional moisture-wicking triboelectric fabric were subjected to performance tests, and the test results are as follows:

[0095] Figure 2 Scanning electron microscope images of (a) the hydrophobic layer and (b) the superhydrophilic layer in the all-fiber unidirectional moisture-wicking fabric prepared in Example 1. Figure 2 It can be seen that the all-fiber unidirectional moisture-wicking fabric has a clear and uniform morphology, with significant differences in fiber diameter and pore size on both sides, and has an obvious pore gradient structure.

[0096] Figure 3This diagram illustrates the dynamic changes in the water contact angle of TPH (fabric obtained by spinning TPU / PVDF-HFP), TPH / F127 (fabric obtained by spinning TPU / PVDF-HFP / F127), and the all-fiber unidirectional hygroscopic triboelectric fabric (LM-AgNPs / Bilayered e-textile) prepared in Example 1. Figure 3 It can be seen that when the LM-Ag NPs loading is 4 mg / cm³, -2 At the same time, a conductive homogeneous layer of a certain thickness is formed, which gives the whole fiber fabric good conductivity while still having the ability to quickly transfer moisture in one direction (98s).

[0097] Figure 4 This is a schematic diagram illustrating the operation of the all-fiber unidirectional moisture-wicking triboelectric fabric prepared in Example 1. Specifically, when the all-fiber unidirectional moisture-wicking triboelectric fabric comes into contact with and separates from the aluminum foil, different charges are generated on the surface. Under electrostatic induction, charge flow occurs between the LM-Ag NPs electrode and the aluminum foil, converting the mechanical signal into an electrical signal. This electrical signal can be used as a power source for electrical appliances or as a sensing signal for human motion, enabling self-driven sensing.

[0098] Figure 5 The image shows the electrical output signal of the all-fiber unidirectional moisture-wicking triboelectric fabric prepared in Example 1; where a is the open-circuit voltage and b is the short-circuit current. Figure 5 It can be seen that the open-circuit voltage reaches 170V and the current output reaches 8μA.

[0099] Example 2

[0100] The amount of AgNPs in step (3) of Example 1 was adjusted to 0g, 0.2g, 0.5g, and 1.0g, while the rest remained the same as in Example 1, to obtain a full-fiber unidirectional moisture-wicking triboelectric fabric.

[0101] Comparative Example 1

[0102] The thickness of the superhydrophilic layer in step (2) of Example 1 was adjusted to 100 μm and the thickness of the hydrophobic layer to 150 μm, while the rest remained the same as in Example 1, to obtain an all-fiber triboelectric fabric.

[0103] Comparative Example 2

[0104] The thickness of the superhydrophilic layer in step (2) of Example 1 was adjusted to 100 μm and the thickness of the hydrophobic layer to 20 μm, while the rest remained the same as in Example 1, to obtain an all-fiber triboelectric fabric.

[0105] Comparative Example 3

[0106] The thermoplastic polyurethane (TPU) particles in step (1) of Example 1 were adjusted to polystyrene-ethylene-butene-styrene block copolymer (SEBS), while other aspects remained the same as in Example 1, to obtain an all-fiber unidirectional moisture-wicking triboelectric fabric.

[0107] Comparative Example 4

[0108] In step (1) of Example 1, the polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer powder was changed to polyvinylidene fluoride powder, while the rest remained the same as in Example 1, to obtain a full-fiber unidirectional moisture-wicking triboelectric fabric.

[0109] Comparative Example 5

[0110] The thickness of the superhydrophilic layer in step (2) of Example 1 was adjusted to 100 μm, the thickness of the hydrophobic layer was adjusted to 100 μm, and the rest was kept the same as in Example 1, so as to obtain a full fiber triboelectric fabric.

[0111] Comparative Example 6

[0112] Omit the 0.3g poloxamer F127 in step (1) of Example 1, and keep everything else the same as in Example 1 to obtain a full-fiber triboelectric fabric.

[0113] Comparative Example 7

[0114] The polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer powder in step (1) of Example 1 is omitted, and the rest is kept the same as in Example 1 to obtain a full-fiber unidirectional moisture-wicking triboelectric fabric.

[0115] The fabrics obtained in Examples 1-2 and Comparative Examples 1-7 were subjected to performance tests, and the test results are as follows:

[0116] Table 1

[0117]

[0118] As can be seen from Table 1:

[0119] Example 1 has excellent mechanical flexibility and stable fabric structure, and has high electrical signal output and a one-way moisture wicking time (98s) that is suitable for the human body;

[0120] Compared with Example 1, the all-fiber unidirectional moisture-wicking fabrics prepared in Comparative Examples 1 and 2 have poor unidirectional moisture-wicking performance. This is attributed to the fact that when the thickness of the TPU / PVDF-HFP hydrophobic layer is too high, droplets cannot effectively penetrate downwards, resulting in poor unidirectional moisture-wicking performance; when the thickness is too low, a pore gradient cannot be effectively formed, and the fabric does not have unidirectional moisture-wicking properties.

[0121] In Example 2, when the amount of AgNPs added is greater than 0.5g, the conductive material on the surface of the material is easy to fall off, which cannot meet the requirements for stable electrical signal output during the wearing process; when the amount of AgNPs added is less than 0.5g, the liquid metal cannot be alloyed and cannot be uniformly coated on the surface of the fiber fabric to form a continuous conductive layer, resulting in poor triboelectric output performance.

[0122] The fabrics prepared in Examples 1, 1, and 2 have higher breaking strength than those in Comparative Example 3, which is determined by the molecular structure and inherent properties of thermoplastic polyurethane.

[0123] The fabrics prepared in Examples 1, 1, and 2 have better triboelectric output performance than those in Comparative Examples 4 and 7. This is attributed to the higher triboelectric negativity of the material itself due to the abundance of fluorine-containing groups in PVDF-HFP.

[0124] The fabric prepared in Example 1 has better air permeability than the fabrics in Comparative Examples 1, 2, 5 and 6. This is because the composite fabric has a suitable gradient pore structure, which enables rapid moisture absorption and perspiration during exercise.

[0125] Example 3

[0126] A method for preparing an all-fiber color-changing unidirectional moisture-wicking triboelectric fabric includes the following steps:

[0127] (1) Preparation of spinning solution:

[0128] 1.05g of thermoplastic polyurethane (TPU) particles, 0.45g of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer powder, and 8.5g of tetrahydrofuran (THF) and N'N-dimethylformamide (DMF) mixed solvent (THF to DMF volume ratio of 3:1) were mixed and stirred at 50℃ and 500rpm for 12h to obtain TPU / PVDF-HFP spinning solution; then 1g of thermochromic microcapsules were added to the TPU / PVDF-HFP spinning solution and mixed evenly to prepare a TPU / PVDF-HFP@TMs spinning solution with a concentration of 15wt%.

[0129] Add 0.3g of poloxamer F127 to 10g of TPU / PVDF-HFP spinning solution, and stir at a constant temperature of 50℃ and 500rpm for 3h to mix evenly. Then add 1g of thermochromic microcapsules and mix evenly to obtain TPU / PVDF-HFP / F127@TMs spinning solution.

[0130] (2) Preparation of all-fiber color-changing unidirectional moisture-wicking fabric:

[0131] The TPU / PVDF-HFP@TMs spinning solution was electrospun (spinning voltage 22kV, spinneret orifice size 22G, injection speed 10mL / h, roller speed 170rpm, receiving distance 12cm, ambient temperature 25℃, relative humidity 40%) to form the first layer of nanofiber fabric as a superhydrophilic layer with a thickness of 100μm.

[0132] The TPU / PVDF-HFP / F127@TMs spinning solution was then electrospun (spinning voltage 16kV, spinneret orifice size 22G, injection speed 1mL / h, roller speed 170rpm, receiving distance 12cm, ambient temperature 25℃, relative humidity 40%) and deposited onto the first layer of nanofiber fabric to form a hydrophobic layer (thickness 90μm). After drying, a full-fiber color-changing one-way moisture-wicking fabric (thickness approximately 200μm) was obtained.

[0133] (3) Preparation of all-fiber color-changing unidirectional moisture-wicking triboelectric fabric:

[0134] 1.5g of EGaIn was weighed and added to 6mL of toluene. The mixture was sonicated at 320W for 1h to obtain a liquid metal nanoparticle dispersion. Subsequently, 0.3g of Ag NPs was introduced into the dispersion and sonicated at 320W for 10min to obtain a uniform and stable LM-Ag NPs conductive coating.

[0135] LM-Ag NPs conductive coating was uniformly coated onto the hydrophilic layer surface of the all-fiber color-changing unidirectional moisture-wicking fabric, with a coating amount of 4 mg / cm². 2 After the solvent evaporates at room temperature for 2 hours, the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric (LM-Ag NPs / Bilayered e-textile@TMs) is obtained.

[0136] Example 4

[0137] The thermochromic microcapsules in TPU / PVDF-HFP / F127@TMs in step (1) of Example 3 are omitted, and everything else remains the same as in Example 3, to obtain a full-fiber color-changing unidirectional moisture-wicking triboelectric fabric.

[0138] Example 5

[0139] The thermochromic microcapsules in TPU / PVDF-HFP@TMs in step (1) of Example 3 are omitted, and everything else remains the same as in Example 3, to obtain a full-fiber color-changing unidirectional moisture-wicking triboelectric fabric.

[0140] Example 6

[0141] The amount of thermochromic microcapsules in TPU / PVDF-HFP@TMs and TPU / PVDF-HFP / F127@TMs in step (1) of Example 3 was adjusted to 0.5g and 1.5g respectively, while the rest remained the same as in Example 3, to obtain a full-fiber color-changing unidirectional moisture-wicking triboelectric fabric.

[0142] The performance of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabrics obtained in Examples 3-6 was tested, and the test results are as follows:

[0143] Figure 6 Stress-strain curves are shown for TPH (fabric obtained by spinning TPU / PVDF-HFP), TPH / F-127 (fabric obtained by spinning TPU / PVDF-HFP / F127), the all-fiber unidirectional moisture-wicking triboelectric fabric (LM-AgNPs / Bilayered e-textile) prepared in Example 1, and the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric (LM-Ag NPs / Bilayered e-textile@TMs) prepared in Example 3. Figure 6 It can be seen that the all-fiber unidirectional moisture-wicking triboelectric fabric has certain mechanical properties (strength of 12MPa and strain of 265%); the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric still has the mechanical flexibility required for human sports wearable processes (strength of 2.5MPa and strain of 175%).

[0144] Figure 7 This is a scanning electron microscope image of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3. Figure 7 It can be seen that the thermochromic microcapsules are uniformly distributed inside the nanofibers.

[0145] Figure 8 The electrothermal temperature response results are for the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3. Figure 8 It can be seen that the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric is sensitive to human body temperature, and the color change is significant in the color development range of 25-40℃.

[0146] Figure 9 This demonstrates the temperature response stability of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3. Figure 9 It can be seen that the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric can achieve rapid electrothermal response within 2.5s at a voltage of 0.3V, and can achieve 50 stable electrothermal cycles from room temperature (30℃) to 75℃.

[0147] Table 2

[0148]

[0149] Table 2 shows that changing the content of thermochromic microcapsules affects the mechanical properties of unidirectional moisture-wicking triboelectric fabrics. When both the superhydrophilic and hydrophobic layers are added at 1.0 g, the composite fabric still maintains a unidirectional moisture transfer gradient and possesses suitable mechanical flexibility (strength of 2.5 MPa and strain of 175%). When the addition amount is less than 1.0 g or the thermochromic layer is a single-layer structure, the thermochromic effect is poor and insufficient to provide a noticeable temperature warning effect. When the addition amount increases, the viscosity of the spinning solution increases, the spinnability deteriorates, and the aggregation of thermochromic microcapsules causes some adhesion between fibers, destroying the gradient pore structure and reducing the air and moisture permeability of the composite fabric. Therefore, a thermochromic double-layer structure with an addition amount of 1.0 g is most suitable.

[0150] Example 7

[0151] A triboelectric generator is formed by using the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared in Example 3 as the negative friction material and electrode, and aluminum foil as the positive friction material and positive electrode. The two electrodes are connected, and through repeated contact-separation processes, mechanical kinetic energy is converted into electrical energy, thus forming a generator.

[0152] Compared to the electrothermal responsive unidirectional moisture-conducting triboelectric fabric obtained in Example 3, the open-circuit voltage of this example is 159V.

[0153] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method of making a full-fiber unidirectional moisture-wicking triboelectric fabric, characterized by, Comprising the following steps: (1) Preparation of the spinning solution: Mixing thermoplastic polyurethane (TPU), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) high molecular polymer and organic solvent uniformly to obtain TPU / PVDF-HFP spinning solution; Add poloxamer F127 to the TPU / PVDF-HFP spinning solution and continue to mix uniformly to obtain TPU / PVDF-HFP / F127 spinning solution; (2) Preparation of the all-fiber unidirectional moisture-wicking fabric: Electrospinning the TPU / PVDF-HFP spinning solution to form a first layer of nanofiber fabric as a hydrophobic layer; Then, electrospinning the TPU / PVDF-HFP / F127 spinning solution onto the first layer of nanofiber fabric as a super-hydrophilic layer using the first layer of nanofiber fabric as the substrate, and after drying and solvent evaporation, an all-fiber unidirectional moisture-wicking fabric is obtained; (3) All-fiber unidirectional moisture-wicking triboelectric fabric: Coating LM-Ag NPs conductive paint on the surface of the super-hydrophilic layer of the all-fiber unidirectional moisture-wicking fabric, and after drying and solvent evaporation, an all-fiber unidirectional moisture-wicking triboelectric fabric is obtained.

2. The method of claim 1, wherein, In step (1), the mass ratio of thermoplastic polyurethane (TPU), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and organic solvent is 1-5 g:0.5-3 g:10 g; the mass ratio of TPU / PVDF-HFP blend system to poloxamer F127 is 10:0.1-0.

3.

3. The method of claim 1, wherein, In step (3), the preparation method of LM-Ag NPs conductive paint is as follows: Mixing liquid metal LM and toluene and ultrasonic treatment to obtain a liquid metal nanoparticle dispersion; then mixing the liquid metal nanoparticle dispersion and silver nanoplate Ag NPs and continuing ultrasonic treatment to obtain LM-Ag NPs conductive paint.

4. The method of claim 1, wherein, The amount of the LM-Ag NPs conductive coating applied in step (3) is 0.1-6 mg / cm 2 .

5. The all-fiber unidirectional moisture-wicking triboelectric fabric prepared by the method of any one of claims 1-4.

6. A method of making a full-fiber, color-changing, unidirectional, moisture-wicking, triboelectric fabric, characterized in that, The method is adding thermochromic microcapsules in the method of preparing the all-fiber unidirectional moisture-wicking triboelectric fabric according to any one of claims 1-4.

7. The all-fiber color-changing unidirectional moisture-wicking triboelectric fabric prepared by the method of claim 6.

8. The application of the all-fiber unidirectional moisture-wicking triboelectric fabric of claim 5 in flexible electrodes, wearable electronic devices or smart textiles.

9. The application of the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric of claim 7 in flexible electrodes, wearable electronic devices or smart textiles.

10. A frictional generator, characterized by It is to use the all-fiber unidirectional moisture-wicking triboelectric fabric of claim 5 or the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric of claim 7 as the electrode and negative friction material, use aluminum foil as the positive electrode and positive friction material, connect the positive electrode and negative electrode, convert mechanical energy into electrical energy through triboelectricity, and form a generator.

11. A wearable electronic fabric, characterized by The all-fiber unidirectional moisture-wicking triboelectric fabric of claim 5 or the all-fiber color-changing unidirectional moisture-wicking triboelectric fabric of claim 7 is used.

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