Preparation And Performance Of Personal Thermal Management Devices Based On Two-dimensional Nanomaterials

Body temperature,the internal temperature of the human body,is the primary condition to maintain a constant body temperature for ensuring human metabolism and various life activities.To maintain the balance of body temperature,the human body needs produce heat and cooling by synergistic effect of endocrine gland,skeletal muscle,skin,blood vessels,sweat glands,and other body organs under the control of the hypothalamus,when the constant state of body temperature is broken as a result of the variations of ambient temperature.It is noteworthy that,however,the“thermostat”of human body is not enough to maintain a constant temperature in a more complex and varied environment,in which case,assistance from external media such as clothing etc.is needed.Personal thermal management?PTM?,namely adjusting the body surface temperature to a healthy state by changing the clothing structure and harvesting human body heat for powering the wearable devices.With the rapid development of materials science,microelectronics,and textile technology,smart-clothing with functions including physical signs monitoring,sports protection,training aids,and mobile medicine etc.has been developed.The PTM has also begun to develop from passive mode to active temperature regulation,and even to intelligent harvesting.Thanks to the appearance of various new two-dimensional materials,a new avenue for development of PTM clothing is opened.Nevertheless,there are still many challenges for PTM materials and devices,such as single function,low conversion efficiency,limited integration ability with clothing,and so on.In our project,we achieved lightweight and flexible PTM devices by developing the new two-dimensional materials.These PTM materials are expected to be used in thermal management clothing to help the human adapt to the complex and changeable environmental,and even harvest human body heat for powering portable electronic equipments.The detailed contents as below:The large-area graphene papers with controllable thickness,high thermal conductivity and high electrothermal responsivity were prepared by using high-throughput method of blade-coating and mild,eco-friendly vitamin C recirculation.Furthermore,the PTM devices were designed by using different technologies including plain weave,co-woven,hollow-out,and kirigami,which can be integrated with normal fabrics.They can be used for keeping human body warm and cooling simultaneously.Meanwhile,the PTM devices also have good extensibility and steam permeability.It will provide an effective solution for the intellectualization of heat regulation of human body surface environment in the future.Free-standing graphene films with porous structure?PGFs?were prepared by using blade-coating method and ice crystal template method.Moreover,p-type PGFs and n-type PGFs were achieved by chemical reduction and physical reduction.All-inorganic flexible TE device with polyimide substrate and stretchable TE device with PDMS substrate were designed based on PGFs active materials.The all-inorganic flexible TE device can work stably at high temperature and the stretchable TE device can withstand the mechanical deformation caused by human motion.These devices shown excellent performance in thermal energy capture and can be used in PTM.Introducing“schottky contact”into the films during the assembling process of 2H phase MoS₂ by in-situ growth of Au nanoparticles,which achieved“decouple”phenomenon between conductivity and Seebeck coefficient within a certain range.A sinificantly increased power factor was also obtained.The flexible TE device shows good TE performance,which has great potential for harvesting human body heat.The p-type and n-type two-dimensional metal chalcogenides including Bi₂Te₃ and Sb₂Te₃ were synthesized by solvothermal method.A fabric-based TE device was designed based on two-dimensional Bi₂Te₃ and Sb₂Te₃ by using a scalable method of dip-coating.The device shows excellent TE performance and moisture-penetrability.