A flexible electrothermal fabric and its preparation method

Abstract

This invention provides a flexible electrothermal fabric and its preparation method. The flexible electrothermal fabric includes a fabric substrate and a conductive composite layer disposed on the surface of the fabric substrate. The conductive composite layer includes a first conductive layer, a second conductive layer, and a third conductive layer stacked sequentially. The first conductive layer is loaded on the surface of the fabric substrate. The first conductive layer is a two-dimensional MXene coating, the second conductive layer is a one-dimensional metal nanowire coating, and the third conductive layer is a graphene layer. The conductivity δ1 of the first conductive layer is 1-4 S / m, the conductivity δ2 of the second conductive layer is 3-16 S / m, and the conductivity δ3 of the third conductive layer is 10-50 S / m, with δ1:δ2:δ3 = 3:5:10. The flexible electrothermal fabric prepared by this invention is easy to wear, has electromagnetic shielding and conductivity functions, and can also maintain electromagnetic shielding and electrothermal cold protection effects in extreme environments, showing good application prospects.

Description

Technical Field

[0001] This invention relates to the field of composite textile materials, and more specifically, to a flexible electrothermal fabric. Background Technology

[0002] With the rapid development of the electronics industry, electronic products have become ubiquitous and essential tools in people's lives. However, while these electronic products bring convenience, they also pose many indirect or direct electromagnetic radiation hazards to the human body. The development of wearable electromagnetic shielding materials that simultaneously possess excellent properties such as flexibility, breathability, and thermal stability remains a significant challenge. Fabrics, especially lightweight, comfortable, and breathable textiles, are considered ideal substrates for developing flexible, breathable, and wearable heaters, better suited to the human body and meeting diverse application requirements.

[0003] Existing technology CN106003930A discloses an electrothermal composite fabric and its preparation method. This method utilizes carbon nanotube membranes impregnated in graphene suspension for a period of time to obtain a nano-conductive film. An elastic fabric is then stretched under a certain tension and bonded to the nano-conductive film. Releasing the elastic fabric allows it to retract, resulting in a lightweight, portable electrothermal composite fabric with high heating efficiency. However, the conductive film of this electrothermal composite fabric has a single-layer structure, which cannot shield against electromagnetic radiation harmful to the human body during high-efficiency heating. Furthermore, the structure of the conductive film layer is relatively simple, leaving room for improvement in electrothermal performance.

[0004] In their paper "Preparation and Photothermal Performance Study of AgNWs / MXene Modified Double-Coated Yarn", Bao Xiaojing et al. disclosed a composite fabric with a two-layer conductive structure consisting of one-dimensional silver nanowires (Ag NWs) and two-dimensional layered conductive material MXene, and its preparation method. Silver nanowires and MXene coatings were loaded onto the modified double-coated yarn by dip-coating. Although the composite fabric has good photothermal performance, the metal nanowire material is prone to oxidation when exposed to air. The chemical stability of MXene itself is insufficient to protect the inner metal nanowire material from oxidation, which easily leads to oxidation and corrosion of the conductive layer, resulting in loss of conductivity and thus affecting product performance. Summary of the Invention

[0005] The present invention addresses how to construct a flexible electrothermal fabric with a robust structure, a conductive composite layer that is not easily oxidized, excellent electromagnetic shielding performance, and conductive function.

[0006] To address the aforementioned problems, this invention provides a flexible electrothermal fabric, comprising a fabric substrate and a conductive composite layer disposed on the surface of the fabric substrate. The conductive composite layer comprises a first conductive layer, a second conductive layer, and a third conductive layer stacked sequentially. The first conductive layer is loaded on the surface of the fabric substrate. The first conductive layer is a two-dimensional MXene coating, the second conductive layer is a one-dimensional metal nanowire coating, and the third conductive layer is a graphene layer. The conductivity δ1 of the first conductive layer is 1-4 S / m, the conductivity δ2 of the second conductive layer is 3-16 S / m, and the conductivity δ3 of the third conductive layer is 10-50 S / m, with δ1:δ2:δ3 = 3:5:10.

[0007] Compared to existing technologies, the flexible electrothermal fabric provided by this invention has a conductive composite layer structure. The first conductive layer is made of two-dimensional MXene material, the second conductive layer is made of one-dimensional metal nanowire material, and the third conductive layer is made of graphene material. The electromagnetic shielding effect is enhanced by utilizing the different conductivity of the different conductive materials to cause reflection loss. The one-dimensional conductive nanomaterial is linear and can effectively anchor adjacent conductive layers, further stabilizing the structure of the conductive composite layer and extending the service life of the flexible electrothermal fabric. Graphene has stable chemical properties and protects the internal structure of the conductive composite layer from corrosion. The use of nanomaterials in the conductive composite layer ensures that the electrothermal fabric can improve electromagnetic shielding efficiency while maintaining a certain degree of breathability and softness, making it suitable for human wear.

[0008] Preferably, the thickness D1 of the first conductive layer is 2-8 μm, the thickness D2 of the second conductive layer is 3-20 μm, and the thickness D3 of the third conductive layer is 10-30 μm. By selecting conductive layers of appropriate thickness, the conductivity difference between the two materials is utilized to further increase the refraction of current between the two materials, thereby enhancing the electromagnetic shielding capability of the flexible photothermal fabric.

[0009] Preferably, the thicknesses D1 of the first conductive layer, D2 of the second conductive layer, and D3 of the third conductive layer satisfy the following relationship: D1 / 4 + 15 ≤ D2 / 3 + 30 ≤ D3 / 2 + 20. Designing the thicknesses D1, D2, and D3 of the first conductive layer to satisfy the above relationship can greatly increase the conductivity difference between the conductive layers, thereby achieving a high-efficiency electromagnetic shielding effect.

[0010] Preferably, the two-dimensional MXene is one of few-layer Ti3C2TX, niobium carbide, molybdenum carbide, and vanadium carbide;

[0011] And / or, the one-dimensional metal nanowire is one or more of silver nanowires, copper nanowires, or nickel nanowires.

[0012] The sheet-like stacked structure of two-dimensional MXene makes the overall structure of the conductive composite layer loose and the packing density low, which enhances the flexibility of the electrothermal fabric. Moreover, electromagnetic waves can generate refraction loss and penetration loss between the two-dimensional sheet-like conductive materials, further enhancing the electromagnetic shielding performance of the electrothermal fabric. The metal nanowires are one-dimensional structures that can effectively anchor the first and third conductive layers, maintain the structure of the conductive composite layer, and the metal nanowires have certain antibacterial functions, improving the comfort of wearing them.

[0013] Preferably, the fabric is a surface-modified fabric, and the material of the fabric is selected from one of cotton, bamboo, silk, wool, polyester, nylon, spandex, glass fiber, and aramid. The surface-modified porous fabric can make the first conductive layer bond more tightly with the fabric substrate, and the conductive composite layer is less likely to detach from the fabric substrate. At the same time, the nanoscale conductive interlayer can improve the breathability of the electrothermal fabric and ensure the wearing comfort of the flexible electrothermal fabric.

[0014] Preferably, the flexible electrothermal fabric has an electric heating temperature of 25-150℃, a resistance of 100-500mΩ / sq, and an electromagnetic shielding effectiveness of 50-100dB in the 2-18GHz range.

[0015] The present invention also provides a method for preparing the above-mentioned flexible electrothermal fabric, comprising the following steps:

[0016] S1. The fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone, and then impregnated in a surface modification solution to obtain a surface-modified fabric.

[0017] S2. Immerse the surface-modified fabric in a two-dimensional MXene suspension using ultrasound, then remove and dry it.

[0018] S3. Coat the surface of the product from step S2 with a one-dimensional metal nanowire solution and allow it to air dry.

[0019] S4. Electroplating is performed on the surface of the product from step S3 to deposit a graphene layer with a thickness of 10-30 μm, resulting in a flexible photothermal fabric with a conductive composite layer.

[0020] Compared to existing technologies, this invention employs ultrasonic-assisted dip coating of the first conductive layer, which effectively maintains the uniformity of the two-dimensional MXene material suspension and reduces solution agglomeration reactions, while also strengthening the connection between the two-dimensional conductive carbon nanomaterial and the fabric substrate. Coating a one-dimensional metal nanomaterial as the second conductive layer is simple to operate and improves the structural stability of the conductive composite layer. The third conductive layer is loaded using an electroplating method, resulting in a robust structure on the outer surface of the conductive composite layer. The uniform distribution of the electroplated layer further protects the internal structure of the conductive composite layer and improves the conductivity of the electrothermal fabric. Moreover, this method is simple to operate and reduces production costs.

[0021] Preferably, in step S2, the concentration of the two-dimensional MXene suspension is 0.8-20 mg / mL, and the conditions for ultrasonic-assisted soaking of the surface-modified fabric are as follows: at a temperature of 10-50℃, using an ultrasonic power of 100-2000W, ultrasonic soaking for 3-30 minutes.

[0022] Selecting an ultrasonically assisted dip-coating of a two-dimensional MXene material with appropriate power can prevent the problem of uneven conductive layer caused by solution agglomeration. Only when the conductive layer is uniform and the thickness is controllable can the electromagnetic shielding performance of the electrothermal fabric be guaranteed.

[0023] Preferably, in step S1, the volume ratio of ethanol to acetone is 1:(1-3), the concentration of the surface modification solution is 3-10 g / L, the modification impregnation temperature is 20-30℃, and the modification impregnation time is 1-3 h.

[0024] Preferably, in step S1, the surface modification solution is a chitosan solution or a polyethyleneimine solution. A fully surface-modified fabric substrate can effectively support conductive materials, improving the structural stability of the conductive composite layer.

[0025] This invention constructs a flexible electrothermal fabric with a conductive composite layer structure. Utilizing the mechanism of ohmic and reflection losses caused by the conductivity mismatch between adjacent conductive layers in the conductive composite layer, the electromagnetic shielding performance of the flexible electrothermal fabric is significantly improved. In addition, the second conductive layer is a one-dimensional metal nanowire structure, which can bridge the two-dimensional MXene material of the first conductive layer and the graphene of the third conductive layer, playing a supporting role and improving the mechanical properties of the coating. The metal nanowire material of the second conductive layer in the conductive composite layer has certain antibacterial functions. The flexible electrothermal fabric prepared by this invention is easy to wear and can also have both electromagnetic shielding capabilities and electrothermal cold protection effects in extreme environments. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation of a flexible photothermal fabric for electromagnetic shielding, provided as a specific embodiment of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] It should be understood that the terminology used in this invention is merely for describing embodiments of features and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] An embodiment of the present invention discloses a method for preparing a flexible electrothermal fabric, the method comprising the following steps:

[0030] S1. The fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone with a volume ratio of 1:(1-3), and then immersed in a surface modification solution with a concentration of 3-10 g / L for 1-3 h at 20-30℃ to obtain a surface-modified fabric.

[0031] The material of the fabric is selected from any one of cotton, bamboo, silk, wool, polyester, nylon, spandex, glass fiber, and aramid; the surface modification solution is selected from chitosan or polyethyleneimine.

[0032] S2. Place the surface-modified fabric into a two-dimensional MXene suspension with a concentration of 0.8-20 mg / mL, and use an ultrasonic cell disruptor at 10-50℃ with an ultrasonic power of 100W-2000W to ultrasonically vibrate and soak for 3-30 minutes. Remove and dry. The thickness of the two-dimensional MXene coating is 2-8 μm.

[0033] The two-dimensional MXene material is selected from one of the following: few-layer Ti3C2TX, niobium carbide, molybdenum carbide, and vanadium carbide.

[0034] S3. A one-dimensional metal nanowire solution is drop-coated, dip-coated, or sprayed onto the surface of the product in step S2 and allowed to dry naturally. The thickness of the one-dimensional metal nanowire coating is 3-20 μm.

[0035] One-dimensional metallic nanowires are selected from one or more of silver nanowires, copper nanowires, and nickel nanowires;

[0036] S4. Electroplating is performed on the surface of the product from step S3 to deposit a graphene layer with a thickness of 10-30 μm, resulting in a flexible electrothermal fabric with a conductive composite layer.

[0037] The preparation process of this invention is as follows: Figure 1 As shown, the flexible electrothermal fabric with a 2D / 1D / 2D three-layer nanomaterial conductive composite structure can be constructed by the above preparation method. It has the advantages of simple operation and high efficiency. The prepared flexible electrothermal fabric has excellent electromagnetic shielding performance, wear resistance and durability, stable structure, high heating efficiency and excellent conductivity.

[0038] The following examples demonstrate electromagnetic shielding effectiveness testing using a vector network analyzer.

[0039] Example 1

[0040] S1. The nylon fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone with a volume ratio of 1:1, and then immersed in a chitosan solution with a concentration of 3g / L for 1h at 20℃ to obtain a surface-modified fabric.

[0041] S2. The surface-modified fabric was placed in a few-layer Ti3C2TX suspension with a concentration of 0.8 mg / mL. Using an ultrasonic cell disruptor, at 10°C and with an ultrasonic power of 100 W, the fabric was ultrasonically shaken and soaked for 10 min. The fabric was then removed and dried. The thickness of the few-layer Ti3C2TX coating was 2 μm.

[0042] S3. Spray a silver nanowire solution onto the surface of the product from step S1 and allow it to dry naturally to obtain a silver nanowire coating with a thickness of 5 μm.

[0043] S4. At room temperature, the product from step S3 is electroplated with a loaded graphene layer with a thickness of 17 μm to obtain a flexible electrothermal fabric with a conductive composite layer.

[0044] The heating temperature of the flexible electrothermal fabric in Example 1 was measured to be adjustable from 26 to 150°C, the electromagnetic shielding effectiveness was adjustable from 50 to 95 dB in the range of 2 to 18 GHz, and the resistance was 100 mΩ / sq. It has excellent electrothermal effect, electromagnetic shielding performance and conductivity.

[0045] Example 2

[0046] S1. The polyester fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone with a volume ratio of 1:3, and then immersed in a chitosan solution with a concentration of 10g / L for 3h at 20℃ to obtain a surface-modified fabric.

[0047] S2. The surface-modified fabric was placed in a niobium carbide suspension with a concentration of 20 mg / mL. Using an ultrasonic cell disruptor, the fabric was ultrasonically vibrated and soaked for 30 min at 50°C with an ultrasonic power of 1000 W. The fabric was then removed and dried. The thickness of the niobium carbide coating was 8 μm.

[0048] S3. Spray copper nanowire solution onto the surface of the product in step S1 and allow it to dry naturally to obtain a copper nanowire coating with a thickness of 18 μm.

[0049] S4. At room temperature, the product of step S3 is electroplated with a graphene layer with a thickness of 30 μm to obtain a flexible electrothermal fabric with a conductive composite layer.

[0050] The heating temperature of the flexible electrothermal fabric in Example 2 was measured to be adjustable from 30 to 150°C, the electromagnetic shielding effectiveness was adjustable from 50 to 100 dB in the range of 2 to 18 GHz, and the resistance was 500 mΩ / sq. It has excellent electrothermal effect, electromagnetic shielding performance and conductivity.

[0051] Example 3

[0052] S1. The wool fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone with a volume ratio of 1:3, and then immersed in a chitosan solution with a concentration of 5g / L for 3h at 20℃ to obtain a surface-modified fabric.

[0053] S2. The surface-modified fabric was placed in a niobium carbide suspension with a concentration of 20 mg / mL. Using an ultrasonic cell disruptor, at 25°C and with an ultrasonic power of 2000 W, the fabric was ultrasonically vibrated and soaked for 25 min. After soaking, the fabric was removed and dried. The thickness of the niobium carbide coating was 6 μm.

[0054] S3. Spray copper nanowire solution onto the surface of the product in step S1 and allow it to dry naturally to obtain a copper nanowire coating with a thickness of 10 μm.

[0055] S4. At room temperature, the product of step S3 is electroplated with a graphene layer with a thickness of 20 μm to obtain a flexible electrothermal fabric with a conductive composite layer.

[0056] The heating temperature of the flexible electrothermal fabric in Example 3 was measured to be adjustable from 25 to 150°C, the electromagnetic shielding effectiveness was adjustable from 50 to 100 dB in the range of 2 to 18 GHz, and the resistance was 300 mΩ / sq. It has excellent electrothermal effect, electromagnetic shielding performance and conductivity.

[0057] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A flexible electrothermal fabric, characterized in that, The invention includes a fabric substrate and a conductive composite layer disposed on the surface of the fabric substrate. The conductive composite layer comprises a first conductive layer, a second conductive layer, and a third conductive layer stacked sequentially. The first conductive layer is loaded on the surface of the fabric substrate. The first conductive layer is a two-dimensional MXene coating, the second conductive layer is a one-dimensional metal nanowire coating, and the third conductive layer is a graphene layer. The conductivity δ1 of the first conductive layer is 1-4 S / m, the conductivity δ2 of the second conductive layer is 3-16 S / m, and the conductivity δ3 of the third conductive layer is 10-50 S / m, with δ1:δ2:δ3 = 3:5:

10. The thickness D1 of the first conductive layer is 2-8 μm, the thickness D2 of the second conductive layer is 3-20 μm, and the thickness D3 of the third conductive layer is 10-30 μm. The thicknesses D1, D2, and D3 of the first, second, and third conductive layers satisfy the following relationship: D1 / 4+15≤D2 / 3+30≤D3 / 2+20.

2. The flexible electrothermal fabric according to claim 1, characterized in that, The two-dimensional MXene is one of the following: few-layer Ti3C2TX, niobium carbide, molybdenum carbide, and vanadium carbide; And / or, the one-dimensional metal nanowire is one or more of silver nanowires, copper nanowires, or nickel nanowires.

3. The flexible electrothermal fabric according to claim 1, characterized in that, The fabric is a surface-modified fabric, and the material of the fabric is selected from any one of cotton, bamboo, silk, wool, polyester, nylon, spandex, glass fiber, and aramid.

4. The flexible electrothermal fabric according to any one of claims 1-3, characterized in that, The flexible electrothermal fabric has an electric heating temperature of 25-150℃, a resistance of 100-500mΩ / sq, and an electromagnetic shielding effectiveness of 50-100dB in the 2-18GHz range.

5. A method for preparing a flexible electrothermal fabric as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. The fabric is ultrasonically cleaned in a mixed solution of ethanol and acetone, and then impregnated in a surface modification solution to obtain a surface-modified fabric. S2. Immerse the surface-modified fabric in a two-dimensional MXene suspension using ultrasound, then remove and dry it. S3. Coat the surface of the product from step S2 with a one-dimensional metal nanowire solution and allow it to air dry. S4. Electroplating is performed on the surface of the product from step S3 to deposit a graphene layer, thereby obtaining a flexible electrothermal fabric with a conductive composite layer.

6. The method for preparing the flexible electrothermal fabric according to claim 5, characterized in that, In step S2, the concentration of the two-dimensional MXene suspension is 0.8-20 mg / mL, and the conditions for ultrasonic-assisted soaking of the surface-modified fabric are as follows: at a temperature of 10-50℃, using an ultrasonic power of 100-2000W, ultrasonic soaking for 3-30 minutes.

7. The method for preparing the flexible electrothermal fabric according to claim 5, characterized in that, In step S1, the volume ratio of ethanol to acetone is 1:(1-3), the concentration of the surface modification solution is 3-10 g / L, the modification impregnation temperature is 20-30℃, and the modification impregnation time is 1-3 h.

8. The method for preparing the flexible electrothermal fabric according to claim 5, characterized in that, In step S1, the surface modification solution is a chitosan solution or a polyethyleneimine solution.

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