Single-battery-driven multilayer polymer electrocaloric device for human body thermal management and preparation method of single-battery-driven multilayer polymer electrocaloric device

Abstract

The invention relates to the technical field of wearable thermal management, and discloses a single-battery-driven multilayer polymer electric card device for human body thermal management and a preparation method thereof.The electric card device comprises a multilayer polymer electric card film made of poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) and Ag films covering the upper surface and the lower surface of the polymer electric card film, and the insulating protection layer is arranged on the bottom layer. The electrocaloric device provided by the invention not only has the advantages of miniaturization, environmental protection, high efficiency and the like, but also reduces necessary high-voltage driving (greater than or equal to 2kV) in the electrocaloric field to safety voltage (36V), has a good electrocaloric effect, is used for human body thermal management, and can expand a human body comfortable temperature zone by 8K. Based on the advantages of the electric card device in the aspects of flexibility and low-voltage driving, the electric card device shows attractive application prospects in the field of wearable human body thermal management.

Description

Technical Field

[0001] The present invention relates to the technical field of wearable thermal management, and in particular to a single-battery driven multi-layer polymer electric card device for human body thermal management and a preparation method thereof. Background Art

[0002] At present, various personalized temperature regulation systems have been developed, which can be divided into passive mode and active mode. Compared with passive personalized temperature regulation systems based on thermal conduction, radiation, humidity and other manipulation methods, active mode can actively optimize the individual's thermophysiological comfort in a wider range of ambient temperatures. Among the four major active temperature regulation strategies, namely electrothermal, microfluidics, thermoelectric effect and differential thermal effect, polymer-based electrocaloric effect has become one of the most competitive and promising alternatives to central air conditioning heating and cooling systems due to its bidirectional temperature regulation, easy integration, excellent wearable flexibility and ultra-low energy consumption. In order to realize the practicality of electrocaloric polymers in personalized temperature regulation, people have made great efforts to improve the performance of electrocaloric polymers, simplify the cumbersome actuator structure of electrocaloric polymer-based devices, and optimize the bulky high-voltage power supply.

[0003] Molecular defect modification and electrocaloric polymer interface engineering have been proven to be effective strategies for enhancing the performance of electrocaloric polymers. In addition to significantly improving the performance of electrocaloric polymers, electrocaloric polymer-based device architectures have also been explored to meet the applicable needs of personalized temperature regulation. For cooling, heat must be transferred from the human body to the electrocaloric polymer; for heating, it must be transferred from the electrocaloric polymer to the human body. Traditional complex actuator structures, such as motors and fluid pumps, increase energy consumption and increase the size and complexity of the system. Therefore, our previous research report proposed an electrostatically driven structure and successfully constructed it to enable wearable electrocaloric polymer-based devices to achieve efficient heat transfer. Thereafter, we integrated a flexible organic photovoltaic module with this electrostatically driven electrocaloric polymer-based device to potentially replace traditional large power sources. Despite a series of breakthroughs in personalized temperature regulation in electrocaloric polymers, electrocaloric polymer-based devices and their power sources, high driving voltage (usually above 2kV) has been the main obstacle for the practical application of electrocaloric polymer-based devices in the field of personalized temperature regulation. Therefore, if devices based on electrocaloric polymers can be driven at low voltages with compact power sources, the gap between the electrocaloric effect and personalized temperature regulation can be bridged, which will help temperature regulation move towards a sustainable energy future. Summary of the invention

[0004] In view of the deficiency that existing polymer-based electrocardioid devices need to rely on high voltage drive, the present invention provides a single-battery driven multilayer polymer electrocardioid device for human body thermal management, and also provides a method for improving the performance of polymer electrocardioids by quenching, and obtaining a safe voltage driven electrocardioid device by reducing the thickness of the polymer.

[0005] To achieve the above object, on the one hand, the present invention provides a method for preparing a single-battery driven multi-layer polymer electric card device for human body thermal management, which comprises the following steps:

[0006] S1. dissolving poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder in N,N-dimethylformamide, and performing ultrasonic degassing in a water bath to obtain a polymer solution with a mass fraction of 0.1 to 1 wt.%, and then coating the polymer solution into a film by drop coating, blade coating, spin coating or spray coating, and evaporating the solvent by heating to obtain an insulating layer;

[0007] S2, forming a Ag film on the surface of the insulating layer by vacuum evaporation;

[0008] S3, dissolving poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder in N,N-dimethylformamide, degassing in a water bath by ultrasonication to obtain a polymer solution with a mass fraction of 8 to 15 wt.%, then coating the polymer solution into a film by drop coating, blade coating, spin coating or spray coating, and evaporating the solvent by heating to obtain a polymer electric card film;

[0009] S4, continuing to generate Ag films and polymer electric card films alternately stacked in sequence according to the method of steps S2 and S3, and the polymer electric card film is at least two layers, and the upper and lower surfaces of each layer of the polymer electric card film are stacked with Ag films, and the overlapping areas of all the polymer electric card films and the Ag films constitute the active area;

[0010] S5, the multilayer structure obtained in step S4 is kept in a vacuum oven at 115-160° C. for 120-180 min, and then immersed in -5-0° C. ice water for quenching;

[0011] S6. Two lead electrodes serving as positive and negative electrodes are respectively set with conductive materials on the outside of the active area of ​​the multilayer structure obtained in step S4. All Ag films are arranged in the order of their overlapping so that the end of the Ag film located at the even-numbered position is electrically connected to one of the lead electrodes outside the active area, and the end of the Ag film located at the odd-numbered position is electrically connected to the other lead electrode outside the active area.

[0012] As a further preferred technical solution of the present invention, the thickness of the insulating layer is 100-500 nm, the thickness of the polymer electric card film is 0.5-10 μm, and the thickness of the Ag film is 10-100 nm.

[0013] As a further preferred technical solution of the present invention, the thickness of the insulating layer obtained in step S1 is 200nm, and the mass fraction of the polymer solution used is 0.1wt.%; the thickness of the polymer electric card film obtained in steps S3 and S4 is 1μm, and the mass fraction of the polymer solution used is 8wt.%; the thickness of the Ag film is 30nm.

[0014] As a further preferred technical solution of the present invention, in steps S1 and S3, poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder is dissolved in N,N-dimethylformamide, stirred at 50-60° C. for 6-12 hours, and then degassed in a water bath with ultrasonication.

[0015] As a further preferred technical solution of the present invention, in steps S1 and S3, before water bath ultrasonic degassing, the N,N-dimethylformamide solution containing the poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder is first filtered using a filter with a pore size of 0.22 microns.

[0016] As a further preferred technical solution of the present invention, in step S5, the vacuum oven temperature is 145°C, the insulation time is 180 min, and the ice water temperature is 0°C.

[0017] As a further preferred technical solution of the present invention, in step S6, the lead electrodes are prepared using a conductive material such as carbon nanotubes, silver nanowires, PEDOT:PSS, graphite or graphene.

[0018] According to another aspect of the present invention, the present invention also provides a single-battery driven multi-layer polymer electric card device for human body thermal management, which is prepared by the above method.

[0019] According to another aspect of the present invention, the single-battery driven multi-layer polymer electric card device for human body thermal management of the present invention is used in human body thermal management.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0021] 1) The present invention adopts a multi-layer stacking method to innovatively construct an electric card device based on multi-layer polymers, which is flexible as a whole and easy to fit with human skin;

[0022] 2) The multilayer polymer electric card device constructed by the present invention can be driven by a single battery at low voltage, making the control system design simpler and the application more convenient;

[0023] 3) The multilayer polymer electrocaloric device constructed by the present invention has a good electrocaloric effect and can be used for human thermal management to expand the human body's comfortable temperature zone by 8K. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0025] Figure 1 This is a schematic diagram of the structure of the electric card device of Example 1.

[0026] Figure 2 This is a graph showing the electric card performance of the electric card device of Example 1 when driven by a 36V safety voltage.

[0027] Figure 3 This is a power consumption comparison test result diagram of the electric card device of Example 1 and a commercial thermoelectric device;

[0028] Figure 4 This is a schematic diagram of the structure of the electric card device of Example 1 applied to human body thermal management.

[0029] Figure 5 This is a diagram showing the thermal management effect of the electric card device of Example 1 applied to human body thermal management.

[0030] Figure 6 The electrocaloric performance test results of the electrocaloric device obtained at different quenching temperatures and times based on the method of Example 1.

[0031] Figure 7 The scanning electron microscope images of cross sections of multiple electrocaloric devices prepared according to the method of Example 1 with a total device thickness of 50 μm are shown.

[0032] In the figure: 1. Insulating layer, 2. Polymer electrocardiographic film, 3. Ag film, 4. Lead electrode, A. Active area.

[0033] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0035] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0036] Embodiment 1:

[0037] This embodiment provides a single-battery driven multi-layer polymer electric card device for human body thermal management, and its structure is as follows: Figure 1As shown, the bottom layer is an insulating layer 1, and upwards are alternately stacked Ag films 3 and polymer electric card films 2, and the overlapping area of ​​all polymer electric card films 2 and Ag films 1 constitutes the active area A of the device, and the left and right sides are lead electrodes 4, and when in use, the multilayer polymer electric card device is connected to the power supply circuit by the lead electrodes 4. The preparation method of the multilayer polymer electric card device is as follows:

[0038] 1) Dissolve poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) powder in N,N-dimethylformamide and perform water bath ultrasonic degassing to obtain a polymer solution A with a mass fraction of 0.1 wt.% and a polymer solution B with a mass fraction of 8 wt.%.

[0039] 2) The polymer solution A is sprayed onto a glass substrate by a spraying method, and the solvent is evaporated on a hot plate at 90° C. for 30 minutes to obtain an insulating layer with a thickness of 200 nm. The insulating layer is used to adhere to human skin.

[0040] 3) forming a 30 nm thick Ag film on the upper surface of the insulating layer by vacuum evaporation;

[0041] 4) Spray the polymer solution B onto the Ag film, and evaporate the solvent on a hot plate at 90° C. for 30 min to obtain a polymer electrocaloric film with a thickness of 1 μm.

[0042] 5) Continue to generate 30nm Ag film and 1μm polymer electrocaloric film alternately stacked in the same manner as steps 3) and 4) (see stacking method for details). Figure 1 As shown in the figure, the total number of polymer electric card film layers is five, and the upper and lower surfaces of each layer of polymer electric card film are overlapped with Ag film (the total number of layers is six), and the overlapping areas of all polymer electric card films and Ag films constitute an active area of ​​4cm×2cm.

[0043] 5) The multilayer structure obtained in step 5) is kept at 145° C. for 180 min in a vacuum oven, and then immersed in 0° C. ice water for quenching.

[0044] 6) After quenching, 5 mg of carboxylated carbon nanotubes are dispersed in a mixture of 18 ml of isopropanol and 2 ml of deionized water, and probe ultrasonication is used for 1 hour, followed by centrifugation at 3500 rpm for 5 minutes, and the supernatant is taken as a carbon nanotube solution; the carbon nanotube solution is sprayed on the left and right ends of the multilayer structure obtained in step 5), and the solvent is evaporated on a hot plate at 90° C. for 30 minutes to obtain two lead electrodes used as positive and negative electrodes, and all Ag films are arranged in a stacked order, and the end of the Ag film at the even-numbered position is electrically connected to one of the lead electrodes outside the active area, and the end of the Ag film at the odd-numbered position is electrically connected to the other lead electrode outside the active area, and finally a flexible multilayer polymer electric card device is obtained.

[0045] The multilayer polymer electric card device obtained in Example 1 was connected to a 36V single battery through two lead electrodes through wires, and its electric card performance under 36V safety voltage was measured. The results are shown in Figure 2. Figure 2 It can be seen that each layer of P (VDF-TrFE-CFE) film with a thickness of 1 micron can achieve a thermal management effect of 1.4K heating and 1.3K cooling when driven by a safe voltage of 36V.

[0046] The power consumption of the multilayer polymer electrocardioid device of Example 1 and the commercial thermoelectric device was compared and tested. To achieve the same 4K cooling / heating effect, the multilayer polymer electrocardioid device needs to apply a 100V voltage, while the commercial thermoelectric device needs a 0.35V voltage. Figure 3 It can be seen that when the heating / cooling effect of 1 watt power is output simultaneously, the working time of the multilayer polymer electric card device of Example 1 (178 hours) is 7.4 times that of the commercial thermoelectric device (24 hours).

[0047] like Figure 4 As shown, the multilayer polymer electric card device of Example 1 is applied to human thermal management. The multilayer polymer electric card device is attached to the human skin through an insulating layer, connected to the power supply circuit of a AA battery (36 volts) through lead electrodes, and controlled by a voltage amplifier in series. It can be seen that the multilayer polymer electric card device of Example 1 has the properties of miniaturization and wearability. The multilayer polymer electric card device of Example 1 is applied to human thermal management, and the surface temperature change of the human body is directly tested with an infrared camera. The thermal management effect is as follows Figure 5 As shown, it can be seen that with the addition and removal of voltage, the human body experiences a 4K heating and cooling effect.

[0048] To further demonstrate the beneficial effects of the present invention, based on the method of Example 1, multilayer polymer electrocaloric devices were prepared at different quenching temperatures and times. The electrocaloric performance test results are as follows: Figure 6 As shown, it can be seen that the performance of the electric card has certain fluctuations. Figure 6 a is the X-ray diffraction pattern of the product after being kept at 115℃~160℃ for 180 minutes and then immersed in 0℃ ice water for quenching. It can be seen that obvious crystal regions are formed at different quenching temperatures; Figure 6 b is the hysteresis loop of quenching in 0℃ ice water after being kept at 145℃ for 10 to 300 minutes. It can be seen that different holding times have excellent polarization strength, and the holding time of 145℃ for 180 minutes has both the maximum polarization strength and the minimum planned loss. Figure 6 c is the temperature change diagram of different field strengths after being kept at 115℃~160℃ for 180 minutes and then immersed in 0℃ ice water for quenching. It can be seen that the temperature change increases with the increase of electric field, and the maximum temperature change is obtained when the temperature is kept at 145℃ for 180 minutes; Figure 6d is the temperature change diagram of different field strengths after being kept at 145℃ for 10 to 300 minutes and then immersed in 0℃ ice water for quenching. The temperature change increases with the increase of the electric field, and the maximum temperature change is obtained when the temperature is kept at 145℃ for 180 minutes. In general, different quenching methods can improve the electrocaloric properties of P(VDF-TrFE-CFE) polymer, and the best electrocaloric properties are obtained when the temperature is kept at 145℃ for 180 minutes.

[0049] To further demonstrate the beneficial effects of the present invention, based on the method of Example 1, multiple electrocardioid devices with a total thickness of 50 μm were prepared by changing the number of layers and thickness of the polymer electrocardioid film. The scanning electron microscope images of the prepared P (VDF-TrFE-CFE) polymer electrocardioid films with different numbers of layers are shown in the following figure: Figure 7 As shown. Figure 7 a It can be seen that the thickness of the single-layer P (VDF-TrFE-CFE) polymer electrocardiographic film is uniformly 50 μm; Figure 7 b It can be seen that the total thickness of the five-layer P (VDF-TrFE-CFE) polymer electrocardiographic film is uniformly 50 μm; Figure 7 c It can be seen that the total thickness of the ten-layer P (VDF-TrFE-CFE) polymer electrocardiographic film is uniformly 50 μm; Figure 7 d It can be seen that the total thickness of the fifteen-layer P (VDF-TrFE-CFE) polymer electrocardiogram film is uniformly 50 microns. It can be seen that the preparation method provided by the present invention can obtain P (VDF-TrFE-CFE) polymer electrocardiogram films with uniform layer thicknesses of different layers, thereby preparing electrocardiogram devices with different numbers of layers to meet different usage requirements. Preferably, the thickness of a single-layer polymer electrocardiogram film is 0.5 to 10 μm.

[0050] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management, characterized in that: The following steps are involved: S1. dissolving poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder in N,N-dimethylformamide, and performing ultrasonic degassing in a water bath to obtain a polymer solution with a mass fraction of 0.1 to 1 wt.%, and then coating the polymer solution into a film by drop coating, blade coating, spin coating or spray coating, and evaporating the solvent by heating to obtain an insulating layer; S2, forming a Ag film on the surface of the insulating layer by vacuum evaporation; S3, dissolving poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder in N,N-dimethylformamide, degassing in a water bath by ultrasonication to obtain a polymer solution with a mass fraction of 8 to 15 wt.%, then coating the polymer solution into a film by drop coating, blade coating, spin coating or spray coating, and evaporating the solvent by heating to obtain a polymer electric card film; S4, continuing to generate Ag films and polymer electric card films alternately stacked in sequence according to the method of steps S2 and S3, and the polymer electric card film is at least two layers, and the upper and lower surfaces of each layer of the polymer electric card film are stacked with Ag films, and the overlapping areas of all the polymer electric card films and the Ag films constitute the active area; S5, keeping the multilayer structure obtained in step S4 in a vacuum oven at 115-160° C. for 120-180 min, and then immersing in -5-0° C. ice water for quenching; S6. Two lead electrodes serving as positive and negative electrodes are respectively set with conductive materials on the outside of the active area of ​​the multilayer structure obtained in step S4. All Ag films are arranged in the order of their overlapping so that the end of the Ag film located at the even-numbered position is electrically connected to one of the lead electrodes outside the active area, and the end of the Ag film located at the odd-numbered position is electrically connected to the other lead electrode outside the active area.

2. The method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management according to claim 1, characterized in that: The thickness of the insulating layer is 100-500 nm, the thickness of the polymer electric card film is 0.5-10 μm, and the thickness of the Ag film is 10-100 nm.

3. The method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management according to claim 2, characterized in that: The thickness of the insulating layer obtained in step S1 is 200 nm, and the mass fraction of the polymer solution used is 0.1 wt. %; the thickness of the polymer electrocardial film obtained in steps S3 and S4 is 1 μm, and the mass fraction of the polymer solution used is 8 wt. %; the thickness of the Ag film is 30 nm.

4. The method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management according to claim 1, characterized in that: In steps S1 and S3, poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder is dissolved in N,N-dimethylformamide, stirred at 50-60° C. for 6-12 hours, and then degassed in a water bath with ultrasonic waves.

5. The method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management according to claim 1, characterized in that: In steps S1 and S3, before water bath ultrasonic degassing, the N,N-dimethylformamide solution containing the poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) powder is filtered using a filter with a pore size of 0.22 micrometers.

6. The method for preparing a single-cell driven multi-layer polymer electric card device for human body thermal management according to claim 1, characterized in that: In step S5, the vacuum oven temperature is 145°C, the insulation time is 180 min, and the ice water temperature is 0°C.

7. The method for preparing a single-battery driven multi-layer polymer electric card device for human body thermal management according to claim 1, characterized in that: In step S6, the lead electrodes are prepared using a conductive material such as carbon nanotubes, silver nanowires, PEDOT:PSS, graphite or graphene.

8. A single-cell driven multi-layer polymer electric card device for human body thermal management, characterized in that: The method is prepared by any one of claims 1 to 7.

9. Application of the single-battery driven multi-layer polymer electric card device for human body thermal management as claimed in claim 8 in human body thermal management.

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