Dynamic structural color in the nacre of Hyriopsis Cumingii and its cause

The structural color and microstructure of the nacre of Hyriopsis Cumingii were investigated by using reflection spectra, theoretical simulation, and scanning electron microscopy, respectively. The results indicate that the structural color of the nacre of Hyriopsis Cumingii can obviously red-shift from blue to red along the growth pattern direction from posterior to anterior of the nacre. The observed, measured, and theoretical simulated results of the structural color are rather consistent, revealing that the structural color of the nacre in the bivalve shell of Hyriopsis Cumingii is derived from the one-dimensional photonic structure which is composed of period oriented alternatively aligned aragonite platelets and protein layers. The lattice period of the one-dimensional photonic structure increased significantly along the growth pattern direction from posterior to anterior of the nacre, which leads to red-shift of the structural color obviously.