A Natural Humidity Sensitive Two-dimensional Tunable Photonic Band a¤Gap Material and its Optic Properties

The structural color and microstructure of the bivalve ligament of Hyriopsis cunimgii were investigated by reflection spectra, scanning electron microscope and theoretical simulation. The results are listed as follows, reflection peak wavelength of the ligament blue-shifts from 460nm to 423nm with the increase of air drying time from 0 to 60min, and the reflectivity decreases gradually, relevant color changes from blue to brown background color. The structural color in the ligament is produced by the 2D photonic structure consisting of aligned aragonite fibers and proteins, in which the diameter of aragonite fiber and the inter-fiber spacing is (122 4)nm and (133 5nm, respectively. Water can reversibly tune the reflectivity of reflection peak and the scope of photonic band gap (PBG), revealing that the ligament is characteristic of humidity sensitive 2D tunable PBG structure. It is concluded that the ligament belongs to the natural humidity sensitive 2D tunable PBG material.a¤