Study Of A Super-non-wetting Self-cleaning Solar Reflective Blue-grey Coating With Luminescence

With the increasingly serious energy crisis and the decrease of non-renewable resources,energy saving and emission reduction become an international consensus.According to statistics,building energy consumption accounts for 40%of the total energy consumption in the world,as well as a series of environmental problems,therefor it is necessary for buildings to cool down,and the wide application of cooling coating can greatly reduce building energy consumption.For cooling coating,surface clean has great influence on the cooling effect,as a result,self-cleaning solar reflective coating appears.This peaper is aimed at use a simple method to prepare a super-hydrophobic self-cleaning solar reflective coating.This peaper start with the design of formulation of the blue-grey coating,reference to the reflectivity of materials which is already known,selecting the appropriate filler,determine the basic formula with low surface free energy by testing the contact angle of the coating surface.Focusing on the possibility of fabricate the rough surface which the super-hydrophobic can be achieved by grinding the coating surfaces using emery papers.Based on the blue-grey coating,the main resaerch work are as follows.Firstly,in order to study the possibility of fabricate the super-non-wetting surface by grinding the coating surfaces using emery papers,we test the contace angle,contact angle hysteresis and rolling angle of the coating surface,the result shows that super-non-wetting solar reflective blue-grey coating with great self-cleaning property could be easily fabricated after the coating surfaces were ground using emery papers with grit numbers 180,240,and 320.Secondly,in order to understand the super-hydrophobic surface achieved by grinding better,SEM and AFM tests were performed on the surface after grinding to learn the micrpscopic morpholorgy of the coating surface.The result of SEM test and AFM test of the rough surfaces indicate that micron grade ravines and rough particles produced by grinding are important factors for superhydrophobicity,as a result,the water droplets on this rough surfaces just like Cassie's modelThirdly,in order to study the ability of cooling effect of the blue-grey coating,we tested the reflective and emissivity of the coating and concrete,the result shows that the blue-grey coating with solar reflectance 0.81 and thermal emittance values 0.88,meeting the requirement of the national standard of architectural reflective thermal insulation coating.By calculating the of cooling effect under the standard environment conditions of a sunny summer day,this coating may generate a temperature reduction of 22.6 ? on a typical hot summer day than the surface of concrete.Lastly,to study the long-term durability of the coating,the coating was subjected to a manual accelerated ageing test for 400 hours(approximately equivalent to 5-10 years of outdoor exposure).In this part,focusing on the superhydrophobicity and the optical properties of the coating after aging text.Although the super-non-wettability of the blue-grey coating surfaces was mainly destroyed,the coating surfaces still remained hydrophobic.The super-non-wettability and the self-cleaning property of the coating surfaces could be completely restored after the coating surfaces were ground usig emery papers again.Besides,the aging test can hardly influence the coating's optical properties.