Hygrochromic Materials Generated by Multilayer of Elytron of the Necrobia rufipes

This paper focuses on to the study of the origins of Blue spectrum reflections of the elytron of Necrobia rufipes, of large family of Cleridae. We combine experimental and numerical method, to explain the structure responsible of the elytron blue color. The experimental results have shown a main peak at 450 nm for dry structure and 548 nm for the impregnated structure, under specular angle incidence 15°. This band reflecting correspond blue and green color. The numerical reproduction of the reflectance spectrum gives 447 nm and 506 nm. These results confirm that the multilayer is responsible for the blue color. We notice that the angle of incidence increases, the main reflection peak moves to smaller waves length. The impregnated structure shows a very interesting property that change color depending on the relative humidity rate. This property can be used in the food industry to control the temperature.