CN117344545B

CN117344545B - Personal thermal management fabric with temperature visualization function and preparation method thereof

Info

Publication number: CN117344545B
Application number: CN202311293346.0A
Authority: CN
Inventors: 马儒军; 俞世雄
Original assignee: Nankai University
Current assignee: Nankai University
Priority date: 2023-10-08
Filing date: 2023-10-08
Publication date: 2025-08-12
Anticipated expiration: 2043-10-08
Also published as: CN117344545A

Abstract

A preparation method for a personal thermal management fabric with a temperature visualization function comprises the following steps: wet spinning polyurethane doped with Ag nanoparticles to obtain silver-containing conductive fibers, annealing on a 160°C hot plate for 5-10 minutes, and then treating with oxygen plasma for 30 seconds; dispersing 0.1-0.3wt% of negatively charged thermochromic powder, 0.3-0.5wt% of aqueous polyurethane, and 0.05wt% of sodium lauryl sulfate in deionized water to prepare an electrophoretic solution; electrophoretically depositing the treated silver-containing conductive fibers with the electrophoretic solution to obtain thermochromic conductive fibers; and weaving the thermochromic conductive fibers through a textile weaving process to obtain a personal thermal management fabric with a temperature visualization function. The fabric of the present invention achieves a dynamic thermal management effect, that is, in a hot environment, it can achieve a cooling effect 2.5K lower than that of ordinary white fabrics. In a cold environment, by combining Joule heat and photothermal effects, it can achieve more energy savings while providing the same heating effect.

Description

Personal thermal management fabric with temperature visualization function and preparation method thereof

Technical Field

The invention relates to the technical field of temperature-sensitive color-changing materials and textiles, in particular to a personal thermal management fabric with a temperature visualization function and a preparation method thereof.

Background

Maintaining the thermal homeostasis of the human body is important for the thermal comfort and health of the human body. The existing heat management technology including air conditioning and ventilation is not only huge in energy consumption, but also unsuitable for outdoor environment. More importantly, the indiscriminate inability to meet everyone's unique thermal management needs. Accordingly, the concept of personal thermal management has grown in recent years, with the heart being that of personal thermal management fabrics. Such personal thermal management fabrics merely regulate the thermal radiation of the human body, rather than regulating the ambient temperature, to provide thermal comfort to the human body. Thus, personal thermal management techniques provide a new strategy that is both energy efficient and effective.

Currently, personal thermal management fabrics are largely divided into heating fabrics and cooling fabrics. For a heated fabric to be useful, it must have excellent solar absorptivity and infrared reflectivity. High solar absorption maximizes heat accumulation while high infrared reflectivity minimizes radiant heat loss from the human body. In contrast, the refrigerating fabric requires extremely high solar reflectance, which can avoid the temperature rise caused by the photo-thermal effect. The spectrum design of the infrared part has two different choices of high transmittance and high emissivity, the high transmittance fabric can reduce the blocking of heat radiation to the greatest extent, the high emissivity fabric takes the fabric as a heat source to indirectly enhance the heat dissipation of a human body, and experiments prove that the two different refrigeration fabrics can achieve good cooling effects. However, such single heated or cooled fabrics are difficult to handle in varying climatic conditions. In addition, the personal thermal management fabric relying on radiation conditioning has limited temperature control capability, and the combination of multiple ways of thermal conditioning means can widen the applicability of the fabric.

Disclosure of Invention

Based on the above, the invention provides a thermochromic conductive fiber to solve the technical problems that the personal thermal management fabric in the prior art is difficult to cope with changeable climatic conditions by means of single heating or refrigerating fabric and has limited temperature control capability.

To achieve the above object, the present invention provides a thermochromic conductive fiber comprising the steps of:

1) The polyurethane doped with Ag nano particles is subjected to a wet spinning process to obtain silver-containing conductive fibers;

2) Annealing the silver-containing conductive fiber on a hot table at 160 ℃ for 5-10min, and then treating the silver-containing conductive fiber by oxygen plasma for 25-30s;

3) Dispersing 0.1-0.3wt% of charged negative thermochromic powder, 0.3-0.5wt% of aqueous polyurethane and 0.05wt% of sodium dodecyl sulfate into deionized water to prepare an electrophoretic fluid; carrying out electrophoretic deposition on the silver-containing conductive fibers treated in the step 2) through electrophoretic liquid, and airing to obtain thermochromic conductive fibers;

4) And (3) obtaining the personal heat management fabric with the temperature visualization function through a weaving and knitting process of the thermochromic conductive fiber.

As a further preferable technical scheme of the present invention, step 1) specifically includes:

Dissolving polyurethane particles in an N, N-dimethylformamide solvent to obtain a PU solution with the concentration of 0.2g/mL, ultrasonically dispersing Ag nano particles with the volume fraction of 40% in the PU solution through a probe, and removing bubbles under negative pressure to obtain an Ag/PU precursor;

Extruding Ag/PU precursor into deionized water at 15-20 mu L/min via a syringe, drawing and stretching, continuously collecting the obtained fiber with a reel, immersing the obtained fiber into ethanol solution, and air drying to obtain conductive fiber containing silver with diameter of 150 mu m.

As a further preferred embodiment of the present invention, in step 3), in the electrophoretic deposition operation, a set of copper sheets is connected to a negative electrode of a power source, silver-containing conductive fibers are connected to a positive electrode of the power source and immersed in the electrophoretic fluid, and a voltage is applied between the negative electrode of the power source and the positive electrode of the power source, so that the thermochromic powder material and the aqueous polyurethane are deposited on the surfaces of the conductive fibers.

As a further preferred embodiment of the present invention, the textile knitting process in step 4) employs a common commercial fabric and thermochromic conductive fibers, the thermochromic conductive fibers being arranged in parallel in a vertical direction, and the common commercial fabric being knitted alternately into each thermochromic conductive fiber in a horizontal direction.

As a further preferable technical scheme of the invention, in the personal heat management fabric with the temperature visualization function, the number density of the thermochromic conductive fibers is 18 pieces/cm.

As a further preferable technical scheme of the invention, the thermochromic temperature of the thermochromic powder is 25-30 DEG C

According to another aspect of the present invention, there is also provided a personal thermal management fabric having temperature visualization functionality. The dynamic heat management with low energy consumption is realized by combining two different modes of Joule heating and solar spectrum adjustment. In particular, in hot environments, the fabric may spontaneously change from colored (colored state) to white to reduce the photo-thermal effect, while the ultra-high infrared emissivity (95%) contributes to heat dissipation, the combination of the two allowing the thermal management fabric to achieve a cooling effect 2.5K lower than that of a normal white fabric, while commercial fabrics of the same color are 7.5-16K higher than that of a normal white fabric. In cold environment, the fabric can be automatically colored to increase the photo-thermal effect, and the conductive core layer can provide high-efficiency Joule heat, and the combination of the conductive core layer and the Joule heat can provide thermal comfort conditions suitable for human bodies. In addition, under the condition of ensuring the same heating temperature, the photo-thermal effect can also greatly reduce the energy consumption of the Joule heat. This thermal management fabric can achieve a 625W/m ² energy saving effect compared to fabrics that are heated by joule heat alone. In addition, the thermochromic fabric also provides an instant and sensitive temperature visualization function, which is helpful for judging the temperature distribution of a human body and providing visual thermal early warning for the human body.

The personal thermal management fabric with the temperature visualization function and the preparation method thereof can achieve the following beneficial effects by adopting the technical scheme:

1) The preparation method provided by the invention is simple and is easy for industrial production and preparation;

2) The invention provides a personal thermal management fabric, which realizes a dynamic thermal management effect, namely, can realize a refrigerating effect which is 2.5K lower than that of a common white fabric in a hot environment, and can realize more energy conservation (625W/m ²) on the premise of providing the same heating effect by combining Joule heating effect and photo-heating effect in a cold environment;

3) The invention provides a personal thermal management fabric, which realizes the effect of temperature visualization, and the thermochromic conductive fabric can realize the visualization of 1064nm laser, so that the shape and the temperature distribution condition of laser spots can be clearly seen when the laser is irradiated on the surface of the fabric, thereby playing the role of thermal early warning.

Drawings

The invention will be described in further detail with reference to the drawings and the detailed description.

FIG. 1 is a schematic view and an optical photograph of a thermochromic conductive fiber of example 1;

FIG. 2 is an electron microscope image of the silver-containing conductive fibers and thermochromic fibers prepared in example 1;

FIG. 3 is a spectral diagram of a red thermochromic conductive fabric, a commercial red fabric, and a commercial white fabric prepared in example 2;

Fig. 4 is a thermal management effect and temperature visualization display of the thermochromic conductive fabric prepared in example 3.

Fig. 5 is a thermal visualization effect of the trichromatic thermochromic conductive fabric prepared in example 4.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

Unless defined otherwise, technical terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concepts pertain. The test reagents used in the following examples are all conventional biochemical reagents unless otherwise specified, and the test methods are all conventional methods unless otherwise specified.

Example 1

This example provides a method for preparing a personal thermal management fabric with temperature visualization, the preparation flow is shown in figure 1. The preparation method comprises the following steps:

Step 1), firstly dissolving Polyurethane (PU) particles in DMF (dimethyl formamide) with the concentration of 0.2g/mL, then ultrasonically dispersing Ag nano particles with the volume fraction of 40% in PU solution through a probe, and removing bubbles through negative pressure to obtain the Ag/PU precursor. Transferring the Ag/PU precursor into a syringe, squeezing the Ag/PU precursor into deionized water by using a syringe pump (20 mu L/min) to remove the solvent, drawing and stretching, continuously collecting the obtained fiber by a winding drum, immersing the obtained fiber into ethanol solution (95%) to thoroughly remove the solvent, and airing in air to obtain the silver-containing conductive fiber (Ag-PU fiber) with the diameter of 150 mu m.

Step 2), obtaining the thermochromic conductive fiber by an electrophoretic deposition method on the basis of the Ag-PU fiber. Firstly, annealing the obtained Ag-PU fiber on a 160 ℃ hot table for 10min, then treating the Ag-PU fiber with oxygen plasma for 30s, then dispersing 1%wt of thermochromic powder, 0.3% of aqueous polyurethane and 0.05% of sodium dodecyl sulfate purchased from Shenzhen color changing technology Co., ltd. In deionized water to obtain a mixture, connecting a group of copper sheets to a power negative electrode, connecting the Ag-PU fiber subjected to oxygen plasma to a power positive electrode and immersing the Ag-PU fiber in the electrophoresis liquid, rapidly depositing the thermochromic material and the aqueous polyurethane on the surface of the conductive fiber when a certain voltage is applied, and airing the conductive fiber in air to obtain the thermochromic conductive fiber.

Step 3) weaving the thermochromic conductive fiber and a small amount of common commercial fabric to obtain the personal heat management fabric with the temperature visualization function. Specifically, thermochromic conductive fibers are arranged in parallel in the vertical direction, and common commercial fabrics are woven into each thermochromic conductive fiber alternately in the horizontal direction, so that the personal thermal management fabric is finally obtained, wherein the number density of the thermochromic conductive fibers is 18 pieces/cm.

Fig. 2 shows the cross-sectional morphology of the Ag-PU fibers prepared in example 1 before and after annealing and the cross-sectional morphology of the thermochromic conductive fibers. Therefore, before annealing, the Ag-PU fiber has a large number of hole structures, and after annealing, the holes in the Ag-PU fiber are obviously reduced, so that the conductivity is greatly improved. On the basis, the thermochromic conductive fiber prepared by utilizing electrophoretic deposition has a core-shell structure, wherein the core layer is Ag-PU fiber, and the shell layer is a mixture of thermochromic material and Waterborne Polyurethane (WPU). The interface morphology shows that the WPU in the shell layer permeates into the Ag-PU fiber in the core layer, so that the mechanical property of the fiber is greatly enhanced, and the thermochromic material can be better attached to the surface of the Ag-PU fiber.

It should be noted that the thermochromic powder of the present invention can be purchased from Shenzhen Huang color-changing technology Co., ltd, is also called reversible thermochromic pigment, and is a powder particle (microcapsule) with repeatedly changing color along with the rising or falling of temperature, the particle is in the shape of sphere, and the average diameter is 2-7 microns. The thermochromic powder may be prepared from an electron-transfer organic compound system. The molecular structure of the organic substance is changed by electron transfer at a specific temperature (thermochromic temperature), thereby realizing color transition, and thus realizing color change from a 'colored-colorless' state and a 'colorless-colored' state. Of course, in practical use, the powder is not limited to the thermochromic powder sold by Shenzhen color changing technology Co., ltd, and other thermochromic powders with the above functional characteristics in the prior art can be used.

Therefore, according to different actual requirements, the invention can be doped with thermochromic powder with single color change or thermochromic powder with multiple colors change in the process of preparing the thermochromic conductive fiber, and the thermochromic powder with multiple colors change can be in different colors according to different temperatures.

Example 2

The red thermochromic conductive fabric was prepared by the preparation method of example 1, and under the condition that the rest of the process conditions were unchanged, only thermochromic powder with a temperature-changing color of red was used as a raw material of the thermochromic conductive fiber, and the thermochromic conductive fabric was thermally decolored, i.e., in a colored state at a low temperature, and when the temperature was increased to a set value, the pigment changed from colored to colorless. The set temperature (thermochromic temperature) is preferably 25 to 30 degrees.

The red thermochromic conductive fabric of this example was compared with a normal fabric, and the test result is shown in fig. 3. Fig. 3 shows the absorbance/emissivity spectra of the red thermochromic conductive fabric prepared in example 1, as well as commercial red and commercial white fabrics. In hot environments, thermochromic conductive fabrics spontaneously turn white, greatly reducing the absorption at 0.4-2 μm to reduce the photo-thermal effect, while corresponding commercial red fabrics are unchanged and still maintain higher absorption. Meanwhile, the red thermochromic conductive fabric has higher emissivity than that of commercial red fabric in the middle infrared part (8-13 mu m), so that spontaneous heat dissipation is higher than that of commercial red fabric, and the combination of the two makes the red thermochromic conductive fabric have excellent refrigerating effect in hot environment. In contrast, in cold conditions, thermochromic conductive fabrics spontaneously turn red to enhance the photo-thermal effect, and the absorptivity is almost equal to commercial red fabrics, with excellent heating effect.

Example 3

Four different-color thermochromic conductive fabrics are prepared by the preparation method of the reference example 1, and under the condition that the rest process conditions are unchanged, only four thermochromic powders with different variable-temperature colors are independently used as raw materials of the thermochromic conductive fibers, and the thermochromic conductive fabrics are in a thermal decoloration type, namely in a colored state at low temperature, and when the temperature is increased to a set value, the pigment changes from color to colorless. The set temperature (thermochromic temperature) is preferably 25 to 35 degrees.

The red thermochromic conductive fabric of this example was compared with a normal fabric, and the test results are shown in fig. 4. Figure 4 shows the thermal management performance of four different colored thermochromic conductive fabrics. In hot environments, the fabric can spontaneously change from color to white to reduce the photo-thermal effect, while the ultra-high infrared emissivity (95%) contributes to heat dissipation, and the combination of the two allows the thermal management fabric to achieve a cooling effect of 2.5K less than that of a normal white fabric, while commercial fabrics of the same color are 7.5-16K higher than that of a normal white fabric. In low temperature environments, the fabric may spontaneously change from white to colored to increase the photothermal effect. The thermochromic conductive fabric has a heating effect slightly lower than that of common commercial fabrics. But the Ag-PU fiber of the core layer can provide efficient joule heating function by an external power supply to make up for the shortage of this part. The combination of the two can provide the thermal comfort condition suitable for human bodies. In addition, under the condition of ensuring the same heating temperature, the photo-thermal effect can also greatly reduce the energy consumption of the Joule heat. This thermal management fabric can achieve a 625W/m ² energy saving effect compared to fabrics that are heated by joule heat alone.

Example 4

Four different-color thermochromic conductive fabrics were prepared by the preparation method of reference example 1, and only thermochromic powder having three colors was replaced with thermochromic powder as a raw material of the thermochromic conductive fibers, namely, purple at less than 20 degrees, red at 20-28 degrees and yellow at more than 28 degrees, under the condition that the rest of the process conditions were unchanged.

Fig. 5 illustrates the thermal visualization function of the thermochromic conductive fabric. The color-changing fabric prepared from the color-changing thermochromic material has high sensitivity to temperature. When invisible 1064nm laser is irradiated on the surface of the fabric, a concentric light spot appears on the surface gradually, and the corresponding infrared thermal image graph also shows the heat distribution condition of the concentric light spot. The function of thermal visualization can provide thermal monitoring and thermal early warning for human bodies, and avoid thermal damage under special environments (high-energy infrared radiation).

While particular embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that these are merely illustrative, and that many variations or modifications may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined only by the appended claims.

Claims

1. A method for preparing a personal thermal management fabric with temperature visualization function, characterized by comprising the following steps:

1) Wet spinning polyurethane doped with Ag nanoparticles to obtain silver-containing conductive fibers;

2) annealing the silver-containing conductive fibers on a hot plate at 160° C. for 5-10 minutes, and then subjecting the fibers to oxygen plasma treatment for 25-30 seconds;

3) dispersing 0.1-0.3 wt% of negatively charged thermochromic powder, 0.3-0.5 wt% of aqueous polyurethane, and 0.05 wt% of sodium lauryl sulfate in deionized water to prepare an electrophoretic solution; subjecting the silver-containing conductive fibers treated in step 2) to electrophoretic deposition using the electrophoretic solution, and drying the solution to obtain thermochromic conductive fibers;

4) Thermochromic conductive fibers are subjected to a textile weaving process to obtain personal thermal management fabrics with temperature visualization function.

2. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, wherein step 1) specifically comprises:

Polyurethane particles were dissolved in N,N-dimethylformamide solvent to obtain a PU solution with a concentration of 0.2 g/mL; Ag nanoparticles with a volume fraction of 40% were dispersed in the PU solution by probe ultrasound, and bubbles were removed by negative pressure to obtain an Ag/PU precursor;

The Ag/PU precursor was squeezed into deionized water through a syringe at a speed of 10-20 μL/min, and the resulting fibers were continuously collected using a reel; the resulting fibers were then immersed in an ethanol solution and dried to obtain silver-containing conductive fibers with a diameter of 150 μm.

3. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, characterized in that in step 3), during the electrophoretic deposition operation, a group of copper sheets are connected to the negative electrode of a power supply, and silver-containing conductive fibers are connected to the positive electrode of the power supply and immersed in an electrophoretic solution. A voltage is applied between the negative and positive electrodes of the power supply to deposit the thermochromic powder material and the water-based polyurethane onto the surface of the conductive fibers.

4. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1 is characterized in that the textile weaving process in step 4) uses ordinary commercial fabric and thermochromic conductive fibers, the thermochromic conductive fibers are arranged in parallel in the vertical direction, and the ordinary commercial fabric is alternately woven into each of the thermochromic conductive fibers in the horizontal direction.

5. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, wherein the number density of the thermochromic conductive fibers in the personal thermal management fabric with temperature visualization function is 18 fibers/cm.

6. The method for preparing a personal thermal management fabric with temperature visualization function according to claim 1, wherein the thermochromic temperature of the thermochromic powder is 25 to 30 degrees.

7. A personal thermal management fabric with temperature visualization function, characterized in that it is prepared by the method according to any one of claims 1 to 6.