Processing method and application of electric heating Mxene-based flexible wearable device

Abstract

The invention discloses a processing method of an electric heating Mxene-based flexible wearable device and application of the electric heating Mxene-based flexible wearable device in outdoor clothes, medical care clothes or intelligent fabrics. The flexible wearable device is presented in a yarn or fabric form and structurally comprises cashmere yarn or cashmere fabric serving as a flexible substrate, an Mxene / electric heating composite material serving as a sensitive material and a sealing layer serving as sealing layer protection from inside to outside, and a coating structure capable of achieving integrated synergism is integrally formed. Wherein Mxene is compounded with materials such as a carbon nano tube, a metal nano material, graphene and the like, so that a good electric heating effect is achieved. The flexible wearable device manufactured by the invention can have higher Joule heating temperature, quick Joule heating response and high heating stability and reliability under lower voltage, and has wide application prospects in the aspects of cold protection and warm keeping, medical care, personal thermal management and the like.

Description

Technical Field

[0001] The present invention relates to a processing method and application of a Mxene-based flexible wearable device with low supply voltage and high-efficiency electric heating, belonging to the field of intelligent wearable textiles. Background Art

[0002] As an important direction in the field of smart textiles, flexible wearable devices have broad application prospects in personal health management, medical care, and environmentally adaptable clothing. However, wearable devices still face many technical challenges in terms of low power consumption, high efficiency, and flexible comfort. In the existing technology, electric heating equipment mainly relies on traditional metal wires or inorganic materials. Although these materials have high electrical conductivity, their rigid structure and low processing adaptability limit their application in flexible wearable devices. In addition, these devices often require a higher operating voltage to generate sufficient Joule heating effect, which increases power consumption and reduces the convenience and economy of practical applications.

[0003] In recent years, two-dimensional MXene materials have become a popular research material for flexible electronic devices due to their excellent conductivity, thermal stability and rich surface chemical functionality. In the field of electric heating, MXene has shown significant advantages of fast response, low power consumption and high thermal efficiency. On the other hand, the choice of flexible substrate materials also has a key impact on the performance and application scenarios of the device. Cashmere yarn and cashmere fabrics, with their unique softness, warmth retention and mechanical toughness, provide an ideal substrate choice for the preparation of highly comfortable and highly adaptable wearable devices. Summary of the invention

[0004] The technical problem to be solved by the present invention is: the problems of high power consumption, low efficiency and insufficient flexibility of existing electric heating equipment.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: to provide a processing method of an electrically heated Mxene-based flexible wearable device, comprising the following steps:

[0006] Step 1): Synthesis of MXene: Select MAX phase as the precursor, control the concentration, temperature and time of the etching solution for selective etching to remove the A layer, and then use an intercalation agent to further expand the MXene interlayer spacing to obtain MXene nanoblocks;

[0007] Step 2): Compounding the Mxene nanoblocks obtained in step 1) with an electrothermal material and uniformly dispersing them in a solvent to achieve an electric heating effect, thereby obtaining a Mxene-based electrothermal composite material as a sensing and electrothermal sensitive material;

[0008] Step 3): the MXene-based electrothermal composite material obtained in step 2) is uniformly coated on a fabric substrate, and impregnated multiple times to enhance the conductive effect, and then vacuum dried to remove excess solvent and fix the composite material to obtain a modified fabric;

[0009] Step 4): The sealing material is evenly applied on the surface of the modified fabric obtained in step 3) for packaging, and the Mxene-based flexible wearable device is obtained after curing.

[0010] Preferably, in step 1), the synthesis of the MXene adopts a hydrofluoric acid direct etching method, and a MXene nanosheet dispersion with an interlayer spacing is obtained through etching reaction and intercalation reaction. The whole process goes through four steps of etching-acid removal-stratification-cleaning, and finally a dispersion of the MXene-based electrothermal composite material with a desired concentration is obtained.

[0011] Preferably, in step 2), the electrothermal material includes at least one of carbon nanotubes, metal nanomaterials, and graphene; the carbon nanotubes include at least one of single-walled carbon nanotubes, multi-walled carbon nanotubes, and few-walled carbon nanotubes; the metal nanomaterial is a silver nanomaterial, including at least one of silver nanowires, silver nanocubes, and silver nanoparticles; the graphene includes at least one of single-layer graphene, graphene oxide, reduced graphene oxide, and functionalized graphene.

[0012] Preferably, step 3) is specifically as follows: first, the fabric is washed in an ethanol solution and deionized water to remove surface impurities, and then dried at 60°C for 4 hours for pre-cleaning treatment; then, the pretreated cashmere substrate is repeatedly immersed in the dispersion of the Mxene-based electrothermal composite material, and each immersion is dried at room temperature after 5 minutes, and this process is repeated for more than 5 times to ensure uniform coating and conductive properties; finally, a post-curing treatment is performed at 60°C to firmly bond the Mxene-based electrothermal composite material to the fabric substrate, thereby completing the preparation of modified cashmere yarn or cashmere fabric.

[0013] Preferably, in step 4), the sealing material is at least one of polyurethane (TPU), Ecoflex silicone rubber, and polydimethylsiloxane (PDMS), which is evenly applied to the modified fabric surface after preparation to ensure full coverage and avoid bubbles or unevenness; after application, it is cured for 24 hours.

[0014] Preferably, the structure of the Mxene-based flexible wearable device includes a flexible substrate, an electrothermal sensitive layer, and an encapsulation protective layer from the inside to the outside. The fabric substrate provides support and flexibility for the entire sensor; the electrothermal composite material evenly coated on the flexible substrate forms the sensitive layer of the sensor, which is responsible for electrothermal conversion; the sealing material covering the surface of the modified cashmere yarn or cashmere fabric is used to encapsulate the entire sensor, protect the internal structure and provide additional stability and durability. The entire structural design is intended to achieve a flexible wearable function with low supply voltage and high-efficiency electric heating.

[0015] Preferably, the fabric base is cashmere yarn or cashmere fabric; the obtained modified cashmere yarn is woven, knitted or braided into a fabric with a desired pattern and structure, and the obtained modified cashmere fabric is combined with other fabric layers using sewing technology to construct a multifunctional smart textile.

[0016] Preferably, the processing method of the electrically heated Mxene-based flexible wearable device comprises the following steps:

[0017] Step a): Layered Ti3C2T x Synthesis of MXene: Ti3AlC2 was taken as the precursor of MAX phase, and its powder was slowly added to 40wt% hydrofluoric acid solution and kept in an ice bath for 5min to avoid temperature rise caused by reaction exotherm; then, the mixture was stirred at 600r / min for 48h at 35°C to achieve selective etching of the Al atomic layer in Ti3AlC2; after etching, the reaction solution was rinsed with deionized water, and the resulting mixture was placed in a centrifuge and centrifuged at 3500r / min for 5min, and the supernatant was poured out; then, deionized water was added again and the Ti3AlC2 dispersion was manually shaken, and the washing process was repeated until the pH value of the supernatant was 5-6; finally, the aqueous dispersion was freeze-dried to prepare Ti3C2T with a layered structure. x MXene materials;

[0018] Step b): Preparation of electrothermal composite material: Dissolve the electrothermal material in deionized water to form a uniform transparent solution, which is then slowly injected into the Ti3C2T x The MXene material dispersion was added and mechanical stirring was performed to ensure uniformity, and then the composite solution was ultrasonically treated for 10 minutes to obtain an electrothermal composite material dispersion, thereby obtaining a composite material with electrothermal properties;

[0019] Step c): Preparation of modified cashmere yarn or cashmere fabric: cutting the cashmere yarn or cashmere fabric to a desired size, cleaning it with an ethanol solution and deionized water, and drying it at 60° C. for 4 hours. Then, immersing the pre-cleaned cashmere yarn or cashmere fabric in the electrothermal composite material dispersion prepared in step b), immersing it for 5 minutes and then drying it at room temperature. Repeat the immersion process for more than 5 times to obtain a modified cashmere yarn or cashmere fabric with conductive properties;

[0020] Step d): Encapsulation of modified cashmere yarn or cashmere fabric: Use a scraper or a brush to mix and prepare the sealing material on the clean and dust-free surface of the modified cashmere yarn or cashmere fabric, covering all areas to form a protective layer, and place the device in a temperature environment of 100-130°C for curing. After the curing is completed, check whether the cured encapsulation layer has defects, and polish or repair it to ensure the integrity and performance of the device, so as to obtain a Mxene-based flexible wearable device.

[0021] Preferably, the MXene-based flexible wearable device is stored in a dry, cool, dust-free environment to maintain its performance and extend its service life. The device is stored in a sealed packaging material, such as a moisture-proof bag or a sealed container, and the temperature of the storage environment is controlled to be at room temperature, avoiding direct sunlight and heavy pressure to ensure that the MXene-based electrothermal flexible wearable device is kept in the best condition before use.

[0022] The present invention also provides the application of the electrically heated Mxene-based flexible wearable device prepared by the above processing method in outdoor clothing, medical care clothing or smart fabrics. In terms of keeping warm, the present invention can be used in winter jackets, gloves, hats, scarves and other outdoor clothing for outdoor workers (such as couriers, construction workers, etc.) and winter sports enthusiasts (such as skiers, climbers, etc.); in terms of medical care, it can be used in medical care clothing for patients, such as hot compress vests, knee pads, etc.; in terms of personal thermal management, it can be used to make smart fabrics, integrated into daily wear clothing, such as smart jackets, smart gloves, etc., to provide personalized temperature regulation and improve comfort.

[0023] The present invention adopts MXene-based electrothermal composite materials, combines flexible cashmere yarn or cashmere fabric as a flexible substrate, and uses impregnation and packaging processes to achieve a flexible wearable device with low supply voltage and high-efficiency electric heating, which meets the actual needs of cold protection, medical care and personalized thermal management.

[0024] The present invention can achieve low power consumption and high-efficiency electric heating performance by optimizing the preparation method of MXene, the composite process of electric heating materials, and the coating and packaging method of flexible substrates, providing technical support for the wide application of smart wearable devices.

[0025] The biggest features of the flexible electrothermal sensor involved in the present invention are low supply voltage, high-efficiency electric heating and excellent flexible adaptability. Its innovation lies in the combination of MXene with carbon nanotubes, graphene or metal nanomaterials, combined with flexible cashmere yarn or fabric substrate to form an integrated sensor structure, which can achieve high-efficiency Joule heating under low voltage conditions, and at the same time has rapid thermal response, long-term stability and high flexibility, and is suitable for multiple scenarios such as cold protection, medical care and personal thermal management. The core technical principle for realizing the above characteristics of the present invention is:

[0026] (1) The core role of MXene-based electrothermal composites: MXene materials can effectively improve the efficiency of electrothermal conversion due to their unique two-dimensional layered structure and high conductivity. In composite materials, MXene works synergistically with carbon nanotubes, graphene or metal nanowires to form efficient electrical and thermal conduction pathways, allowing electrical energy to be quickly converted into thermal energy, thereby achieving efficient heating at low voltage.

[0027] (2) Mechanical support and functional integration of flexible substrate: Cashmere yarn or fabric is selected as the flexible substrate. Its excellent softness and ductility provide mechanical support for the sensor, while achieving good fit with the skin or complex curved surfaces to ensure wearing comfort. At the same time, the substrate is dipped and coated with electrothermal composite materials multiple times to form a uniform sensitive layer, giving the substrate good conductivity and electrothermal properties.

[0028] (3) Protection and optimization of packaging materials: Polyurethane (TPU), Ecoflex silicone rubber or PDMS are used as packaging materials to provide necessary protection while ensuring the flexibility, air permeability and electrical insulation of the sensor. The packaging layer not only extends the service life of the device, but also enhances its environmental adaptability and expands its application range.

[0029] (4) Joule heating principle and practical application: When a low voltage is applied, the current passes through the electrothermal composite sensitive layer with excellent conductivity, triggering the Joule heating effect (Joule Heating). The thermal network in the composite material quickly and evenly transfers heat to the substrate surface, achieving rapid heating. The electrothermal sensor of the present invention can quickly heat up to an applicable range (such as 40°C-70°C) at a low voltage (below 12V), meeting the actual needs of cold protection, thermal therapy and personalized temperature regulation.

[0030] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0031] (1) Achieve efficient electric heating at low supply voltage and improve energy efficiency ratio: The present invention forms an efficient electrical and thermal network through the synergistic compounding of MXene and carbon nanotubes or graphene or metal nanomaterials, so that the electric thermal sensor can quickly heat up to the applicable temperature range under low supply voltage conditions. Compared with traditional high-voltage equipment, it significantly reduces power consumption, improves electric-thermal conversion efficiency, and meets the needs of energy conservation, environmental protection and portable applications.

[0032] (2) Innovative combination of flexible cashmere substrate and electrothermal composite material: The present invention uses flexible cashmere yarn or fabric as the substrate to give the sensor excellent flexibility and fit, making it able to adapt to complex curved surfaces or dynamic motion scenes. After the substrate is coated with the electrothermal composite material multiple times, it not only achieves excellent electrothermal performance, but also maintains the softness and mechanical stability of the cashmere material, significantly improving the wearing comfort and durability of the device.

[0033] (3) The packaging material layer enhances environmental adaptability and service life: The present invention uses a sealing material with good air permeability and excellent electrical insulation (such as TPU, Ecoflex or PDMS) as a protective layer to ensure that the sensor has stable performance under humidity, high temperature or external force. At the same time, the selection of sealing materials and the optimization of the coating process effectively avoid material cracking or aging problems, significantly improving the long-term reliability and multi-scenario adaptability of the sensor.

[0034] (4) The processing technology is simple and suitable for large-scale production: The present invention adopts the dip coating and vacuum drying technology, which has a simple process flow and is suitable for the treatment of various flexible substrates (such as yarns and fabrics). The function can be optimized by controlling the number of coatings and drying conditions. Compared with the traditional multi-step complex process, the present invention provides feasibility for the large-scale production of flexible electric heating devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of the electrically heated Mxene-based flexible wearable device prepared by the present invention;

[0036] Figure 2 The present invention provides a process flow chart of the processing method. DETAILED DESCRIPTION

[0037] In order to make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0038] like Figure 1 As shown, the low supply voltage, high-efficiency electric heating Mxene-based flexible wearable device prepared by the present invention adopts a multi-layer structure design, specifically including a flexible base layer, an electric thermal sensitive layer and a packaging protection layer.

[0039] Processing method process such as Figure 2As shown, it includes four steps:

[0040] First, the MXene material with large interlayer spacing was synthesized by the hydrofluoric acid method with controlled etching solution concentration and temperature;

[0041] Secondly, MXene is compounded with electrothermal materials such as carbon nanotubes, graphene or metal nanomaterials, and a uniform electrothermal composite dispersion is formed by mechanical stirring and ultrasonic dispersion;

[0042] Next, the electrothermal composite dispersion is applied multiple times onto a flexible cashmere yarn or fabric substrate using a dip coating process, and the coating is fixed by vacuum drying to enhance the electrical conductivity and thermal response performance;

[0043] Finally, a sealing material with excellent air permeability is evenly coated on the surface of the substrate and cured under appropriate temperature conditions to form a stable, flexible and efficient electrothermal temperature sensor.

[0044] Example 1

[0045] This embodiment provides a Mxene-based electrothermal flexible wearable device based on cashmere yarn, and the specific method thereof includes:

[0046] Take 5g Ti3AlC2 powder and slowly add it to 50mL 40wt% hydrofluoric acid solution, stir it in an ice bath for 5min to prevent overheating, then place the mixture at 35℃ and stir it at 600r / min for 48h to complete etching and obtain MXene nanosheets. After the reaction is completed, centrifuge and wash until the pH value of the supernatant is 5-6, and prepare a MXene dispersion with a concentration of 2g / L. Take 0.5g single-walled carbon nanotubes (SWCNT) and dissolve it in 20mL deionized water, mix it with 50mL MXene dispersion and ultrasonicate it for 10min to form a uniform electrothermal composite dispersion. Select cashmere yarn with a diameter of 20μm and a length of 15cm, wash it with ethanol for 10min, rinse it with deionized water, dry it at 60℃ for 4h, immerse it in the electrothermal composite dispersion, and dry it at room temperature after immersion for 5min each time. Repeat 6 times to ensure uniform attachment, and finally dry it in vacuum at 60℃ for 4h. 10 wt % polyurethane (TPU) solution was evenly coated on the yarn surface to ensure no bubble coverage, and cured at 50 ° C for 24 h to complete the preparation of the electrothermal temperature sensor.

[0047] Example 2

[0048] This embodiment provides a Mxene-based electrothermal flexible wearable device based on cashmere fabric, and the specific method thereof includes:

[0049] Take 5g Ti3AlC2 powder and slowly add it to 50mL 40wt% hydrofluoric acid solution, stir it in an ice bath for 5min to prevent overheating, then place the mixture at 35℃ and stir it at 600r / min for 48h to complete etching, the obtained MXene nanosheets are centrifuged and washed to pH 5-6, and a MXene dispersion with a concentration of 3g / L is prepared. Take 1g graphene oxide (GO) and dissolve it in 50mL deionized water, stir it mechanically for 30min, add 100mL MXene dispersion, and ultrasonicate it for 15min to form a uniform electrothermal composite dispersion. Select a cashmere fabric with a thickness of 10cm×10cm and a thickness of 0.2mm, wash it with ethanol solution for 10min, rinse it with deionized water, dry it at 60℃ for 4h, and then immerse it in the electrothermal composite dispersion. After each immersion for 5min, vacuum dry it at 40℃, and repeat it 5 times to enhance the conductivity and thermal response performance. Finally, 15 wt% Ecoflex silicone rubber solution was evenly coated on the surface of the cashmere fabric, and a scraper was used to ensure bubble-free coverage. The solution was cured at 60 °C for 12 h to prepare a flexible electrothermal temperature sensor.

Claims

1. A method for processing an electrically heated Mxene-based flexible wearable device, characterized in that: The following steps are involved: Step 1): Synthesis of MXene: Select MAX phase as the precursor, control the concentration, temperature and time of the etching solution for selective etching to remove the A layer, and then use an intercalation agent to further expand the MXene interlayer spacing to obtain MXene nanoblocks; Step 2): Compounding the Mxene nanoblocks obtained in step 1) with an electrothermal material and uniformly dispersing them in a solvent to achieve an electric heating effect, thereby obtaining a Mxene-based electrothermal composite material as a sensing and electrothermal sensitive material; Step 3): the MXene-based electrothermal composite material obtained in step 2) is uniformly coated on a fabric substrate, and impregnated multiple times to enhance the conductive effect, and then vacuum dried to remove excess solvent and fix the composite material to obtain a modified fabric; Step 4): The sealing material is evenly applied on the surface of the modified fabric obtained in step 3) for packaging, and the Mxene-based flexible wearable device is obtained after curing.

2. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: In step 1), the synthesis of the MXene adopts a hydrofluoric acid direct etching method, and a MXene nanosheet dispersion with an interlayer spacing is obtained through etching reaction and intercalation reaction. The whole process goes through four steps of etching-acid removal-stratification-cleaning, and finally a dispersion of the MXene-based electrothermal composite material with a desired concentration is obtained.

3. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: In step 2), the electrothermal material includes at least one of carbon nanotubes, metal nanomaterials, and graphene; the carbon nanotubes include at least one of single-walled carbon nanotubes, multi-walled carbon nanotubes, and few-walled carbon nanotubes; the metal nanomaterial is a silver nanomaterial, including at least one of silver nanowires, silver nanocubes, and silver nanoparticles; the graphene includes at least one of single-layer graphene, graphene oxide, reduced graphene oxide, and functionalized graphene.

4. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: Step 3) is specifically as follows: first, the fabric is washed in an ethanol solution and deionized water to remove surface impurities, and then dried at 60°C for 4 hours for pre-cleaning treatment; then, the pretreated cashmere substrate is repeatedly immersed in the dispersion of the Mxene-based electrothermal composite material, and each immersion is dried at room temperature after 5 minutes, and this process is repeated more than 5 times to ensure uniform coating and conductive properties; finally, post-curing treatment is performed at 60°C to firmly bond the Mxene-based electrothermal composite material to the fabric substrate, thereby completing the preparation of modified cashmere yarn or cashmere fabric.

5. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: In step 4), the sealing material is at least one of polyurethane, Ecoflex silicone rubber, and polydimethylsiloxane, which is evenly applied to the modified fabric surface after preparation to ensure full coverage and avoid bubbles or unevenness; after application, it is cured for 24 hours.

6. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: The structure of the Mxene-based flexible wearable device includes a flexible substrate, an electrothermal sensitive layer, and a packaging protection layer from the inside to the outside.

7. The processing method of the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: The fabric base is cashmere yarn or cashmere fabric; the obtained modified cashmere yarn is woven, knitted or braided into a fabric with a desired pattern and structure; the obtained modified cashmere fabric is combined with other fabric layers using stitching technology to construct a multifunctional intelligent textile.

8. The method for processing the electrically heated Mxene-based flexible wearable device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step a): Layered Ti3C2T x Synthesis of MXene: Ti3AlC2 was used as the precursor of MAX phase, and its powder was slowly added into 40wt% hydrofluoric acid solution and kept in an ice bath for 5min to avoid the exothermic reaction and temperature rise. Subsequently, the mixture was stirred at 600r / min at 35°C for 48h to achieve selective etching of the Al atomic layer in Ti3AlC2. After etching, the reaction solution was rinsed with deionized water, and the resulting mixture was placed in a centrifuge and centrifuged at 3500r / min for 5 minutes, and the supernatant was poured out; then, deionized water was added again and the Ti3AlC2 dispersion was manually shaken, and the washing process was repeated until the pH value of the supernatant was 5-6; finally, the aqueous dispersion was freeze-dried to prepare Ti3C2T with a layered structure. x MXene materials; Step b): Preparation of electrothermal composite material: Dissolve the electrothermal material in deionized water to form a uniform transparent solution, which is then slowly injected into the Ti3C2T x The MXene material dispersion was added and mechanical stirring was performed to ensure uniformity, and then the composite solution was ultrasonically treated for 10 minutes to obtain an electrothermal composite material dispersion, thereby obtaining a composite material with electrothermal properties; Step c): Preparation of modified cashmere yarn or cashmere fabric: cutting the cashmere yarn or cashmere fabric to a desired size, cleaning it with an ethanol solution and deionized water, and drying it at 60° C. for 4 hours. Then, immersing the pre-cleaned cashmere yarn or cashmere fabric in the electrothermal composite material dispersion prepared in step b), immersing it for 5 minutes and then drying it at room temperature. Repeat the immersion process for more than 5 times to obtain a modified cashmere yarn or cashmere fabric with conductive properties; Step d): Encapsulation of modified cashmere yarn or cashmere fabric: Use a scraper or a brush to mix and prepare the sealing material on the clean and dust-free surface of the modified cashmere yarn or cashmere fabric, covering all areas to form a protective layer, and place the device in a temperature environment of 100-130°C for curing. After the curing is completed, check whether the cured encapsulation layer has defects, and polish or repair it to ensure the integrity and performance of the device, so as to obtain a Mxene-based flexible wearable device.

9. The method for processing the electrically heated Mxene-based flexible wearable device according to claim 1, characterized in that: The Mxene-based flexible wearable device is stored in a dry, cool, dust-free environment to maintain its performance and extend its service life.

10. Application of the electrically heated Mxene-based flexible wearable device prepared by the processing method according to any one of claims 1 to 9 in outdoor clothing, medical care clothing or smart fabrics.

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