Angular-Independent Structural Colors of Clay Dispersions

Clay mineral nanosheet colloids were found to show angular-independent structural colors after desalting. Naked-eye observation and UV-visible reflectance spectra showed that the color is tuned by varying the average nanosheet size and nanosheet concentration. The low angular-dependence of the structural color was also clarified by these observations, which is the first case for a nanosheet system. The present system is expected as an environmentally benign and low-cost structural color material for various applications.