Preparation And Properties Of Multifunctional Flexible Thermal Management Film Materials

In recent years,with the increasing awareness of energy consumption and the continuous pursuit of comfort and health,personal thermal Management(PTM)has gradually become a research hotspot.Compared with traditional space thermal management solutions,PTM can reduce the energy consumption caused by building space heating or cooling and achieve efficient energy utilization.It can meet the different needs of different individuals for thermal comfort;It can be applied in multiple scenarios in indoor and outdoor environments.In this thesis,we prepared Ag/ paper@LDH and Al/PDMS-ZnO/ZnO PTM materials with dual functions of cooling/insulation,and carried out a series of analysis and characterization and performance tests on them.The main research work includes the following parts:(1)The paper@LDH composite material with high infrared emissivity was prepared by hydrothermal method,and the Ag film layer was prepared by evaporation method on one side of the composite material to obtain Ag/paper@LDH PTM material.The surface morphology and chemical composition were characterized by SEM,XPS and XRD.The optical experimental results show that the average emissivity of paper@LDH PDMS-ZnO composite material is 95.9% in 7-14 ?m band,and the average emissivity of Ag film is7.1%.(2)PDMS-ZnO porous flexible composite material with daytime radiation cooling effect was prepared by the method of segmented heating curing,using PDMS,Na Cl solution and nano-ZnO as raw materials.Al film was prepared by magnetron sputtering on zhe PDMS-ZnO composite material.The surface morphology and chemical composition of the film were analyzed by SEM,FTIR,XPS and XRD.The results of reflectance test show that the PDMS-ZnO composite material with 6%wt ZnO content has the highest average reflectance of 90.6% at 0.4?2?m.The infrared emissivity test results show that the film material has high and low mid infrared emissivity,with average emissivity of 94.1% and 3.8%,respectively.(3)Superhydrophobic ZnO surfaces were prepared by spraying on Al/PDMS-ZnO composite material using PDMS and hydrophobic ZnO nanoparticles as raw materials.Combined with SEM test and hydrophobicity test,the superhydrophobicity of hydrophobic surface prepared by 0.04 g/ m L ZnO dispersion is the most obvious,with a water contact Angle of 166.1° and a roll Angle of 1.5°.The optical properties of ZnO superhydrophobic film prepared on the PDMS-ZnO composite material are further improved,with an average reflectance of 89.4% in the band of 0.4?2?m and an average emissivity of 97.1% in the band of 7?14?m.The test results of thermal management effect show that Al/PDMS-ZnO/ZnO thermal management material can decrease 4.7 ? and increase 4.3 ? compared with ordinary cotton cloth in cooling and heating mode,respectively,and has obvious daytime radiation cooling and heating effect.In this thesis,experiments are designed to prove that the material has good flexibility,permeability and antifouling effect.