Spots with dual structural colors on the skin of some organisms in nature are of tremendous interest due to the unique function of their dye-free colors. However, imitation of them requires complicated manufacturing processes, expensive equipment, and multiple predesigned building blocks. In this work, a one-pot strategy based on the phase-separation-assisted nonuniform self-assembly of monosized silica nanoparticles is developed to construct domes with dual structural colors. In drying poly(ethylene glycol)-dextran-based (PEG-DEX) droplets, monosized nanoparticles distribute nonuniformly in two compartments due to the droplet inner flow and different nanoparticle compatibility with the two phases. The dome colors are derived from the self-assembled nanoparticles and are programmable by regulating the assembly conditions. The one-pot strategy enables the preparation of multicolor using only one type of building block. With the dual-color domes, encrypted patterns with a high volume of contents are designed, showing promising applications in information delivery.
Keywords: aqueous two-phase system; dual structural colors; phase separation; photonic crystals; self-assembly.