Controllable synthesis of nano Ag-Au/butterfly wings composites with mimicking fine hierarchical structure of butterfly wings

A nature bio-template strategy was implemented to synthesize nano Ag-Au particles and display ordered arrays on butterfly wings. By a convenient procedure, the butterfly wings were immersed in ethylenediamine to increase the reactive sites on the chitin component (e.g. -CONH-and -OH functional groups), in which nano Ag particles can in situ come into being and further serve as the active sites for succedent Au deposition. The 30-50 nm solid spherical, 50-80 nm hollow spherical, irregular Ag-Au particles are loaded both on the wings' surface layer and inside the ordered array nanostructure homogeneously. This work not only replicates the fine structure of the butterfly wing, but also regulates the shape of nano Ag-Au particles. The preparation method of liquid phase impregnation based on natural biological templates provides an important reference for the effective preparation of the Ag-Au/butterfly wing composites with fine graded structure and multi-component functional nanostructures.