Radiative Cooling Characteristics And Broadband Reflection Optical Mechanism Of Butterfly Wings

Recently,structural color has attracted wide attention in the fields of material science,biology,physics,etc.However,compared with iridescence,the studies on structural whiteness generated by broadband reflection are very limited and there has been no systematic review up to now.However,the mechanism of broadband reflection of natural microstructures can provide inspiration for artificial bionics light regulating functional materials,which has wide application in many fields such as precision optical instruments etc.The dissertation focuses on white butterflies.We investigate the relationship between microstructure of white butterfly scales and optical reflectance spectra,and choose the butterfly with significant broadband reflection characteristics.The thermal regulation effect of butterfly wings is explored,which could provide important inspiration for preparing high performance temperature control materials.3D models of the scale microstructure of this butterfly are established to analyze white structural color generation mechanism.The main results are as follows:1.Eight kinds of white butterflies are chosen to compare their visible light reflection spectral and microstructure characterization.The results indicate that the Curetis acuta Moore butterfly has the most significant broadband reflection characteristics.Furthermore,infrared spectra and temperature characteristic tests are implemented and the results show that this kind of butterfly can lower the reflection of mid-infrared light which is in line with the characteristics of selective radiator,and the butterfly wing covered with white scales can reduce about 5 ~oC compared to that without white scales.2.Color change is observed in the individual scale of Curetis acuta Moore butterfly after adding alcohol color,and when the scales are overlapped,the color of the overlapped part fades and the brightness becomes higher,which suggests that the mechanism for structural whiteness of the butterfly is color mixing.Furthermore,a simplified 3D model is established through investigating the effect of each unit in the butterfly scale on broadband reflection through FDTD simulations.