The Design,Preparation,and Performance Study Of Flexible Wearable Personal Thermal Management Devices

Personal thermal management is a method of adjusting the temperature of the microenvironment on the body surface by adjusting the infrared performance and thermal conductivity of the fabric to maintain a comfortable temperature.Personal thermal management devices have broad application prospects due to their energy-saving,light-weight and other advantages.This paper focuses on the design,preparation and performance of flexible wearable personal thermal management devices.The main contents are as follows:1.We designed thermal insulation devices based on infrared reflection/visible light absorption enhancement.A CNT model was constructed using FDTD simulation software to calculate the effect of different spacing and diameter on the infrared reflectance performance of the CNT film.The results show that the infrared reflectance of the CNT film is as high as 70%.Based on the results of simulation calculations,this paper developed a personal thermal management device based on CNT film insulation.First,a CNT/nano PE film was prepared using a vacuum filtration process.The infrared reflectance of the film in the human body radiation band(8-14?m)is as high as 78%.In addition,the visible light absorption rate of the film is as high as?90%,so the film has good thermal insulation performance.The temperature test shows that the thermal insulation effect of the film is?6?higher than that of cotton fabric.In addition,based on the CNT/nano PE film,a face-to-face structure is used to prepare a multifunctional device with pressure sensing performance,thermal insulation performance,and electric heating function.Based on this multifunctional device,a smart wristband is prepared,which can monitor the human pulse signal In addition,the wristband has a dual-mode heat preservation function,which can provide Joule heat with an external voltage(3.5 V)and increase the body surface temperature to 55?.Due to its excellent performance,the multifunctional device has a wide range of application prospects in health monitoring,medical and other fields.2.We designed a cooling device based on infrared emission/visible light reflection enhancement.FDTD simulation software was used to build a Si O₂ microsphere model to calculate the infrared emissivity performance of Si O₂microspheres under different spacing and diameter conditions.The calculation results show that Si O₂ microspheres have the highest infrared emissivity at a diameter of 4?m.According to the results of simulation calculations,this paper has developed a Si O₂microsphere/nano PE refrigeration film.The Si O₂ microsphere/nano PE film was prepared by spraying process,and the effect of different doses and diameters on the infrared emissivity of the refrigeration film was studied.The film has the highest emissivity(?75%)under the condition of 4?m diameter.It can improve the radiation efficiency of human body and realize the cooling function.A Zn O nanoparticle model was further constructed,and the visible light reflectance performance of Zn O nanoparticles was calculated.The calculation results show that Zn O nanoparticles have a visible light reflectivity of?80%.Based on the simulation calculation results,a Si O₂/nano PE/Zn O refrigeration film was developed..The film is prepared by spraying process.The film has high infrared emissivity and visible light reflectivity up to 85%,which can effectively reduce the heat input of sunlight.Tested in an outdoor environment,the surface temperature of the Si O₂/nano PE/Zn O film is reduced by?15.2?compared with the cotton fabric,showing an excellent cooling effect.3.We designed a two-dual thermal management device based on the principle of tunable infrared emissivity.Using the principle of adjustable electrodeposition to change the infrared emissivity,a tunable dual personal thermal management device is designed and prepared.The device consists of upper electrode,gel electrolyte and lower electrode.In initial state,because the device has a high infrared transparent upper electrode,the device shows the high infrared emissivity at this time,which improves the efficiency of human radiation.At this time,it is in the cooling mode;when the device is applied with a voltage,the gel The copper ions in the electrolyte are deposited on the surface of the upper electrode.At this time,the device shows the low emissivity of copper metal,which reduces the efficiency of human radiation.At this time,it is in the heat preservation mode.After the reaction process,a reverse voltage can be applied to convert the deposited copper metal layer into copper ions to achieve cyclic dual-mode tuning.The FTIR test shows that by adjusting the surface voltage(0-20 V)and deposition time(0-100 s),the infrared emissivity(50%-85%)of the device can be effectively adjusted.In the infrared image test,the surface temperature of the device can be up to 6.2?when the device responds to a positive voltage of 20 V for 80 s compared with the unreacted state,showing an excellent dual-mode personal thermal management function.