| 초록 |
Photonic crystals which show structural colors are generated by self-assembly of colloidal particles. However, it is challenging to produce large-sized single crystal in microcapsules. Here, we design a centrifugation-assisted crystallization of attractive colloidal particles to produce single crystal in double emulsion droplets. Polystyrene nanoparticles, co-existing with depletant and salt in the core of microcapsules, are slowly deposited unidirectionally by centrifugation. Diffused particles forms a few crystallites by depletion attraction, and they are merged into a single or few large crystallites by Ostwald ripening. Photonic capsules containing single crystal show high reflection and angle-dependent color change. They can be served as micro-compartments of photonic graphics or anti-counterfeiting. |
