Shape control of colloidal crystals by microfluidics and their applications to optical functional materials

胶体晶体，单分散粒子的三维周期性阵列，在可能的应用方面受到了相当大的关注，特别是作为光子晶体。胶体晶体通常是在衬底上制造的，薄膜形状限制了这些晶体在许多应用中的效用。在这项工作中，我们已经成功地利用微流体技术制造了各种形状的胶体晶体，如贝壳、纤维和大薄膜。我们证明了凝胶固定的胶体晶体壳具有潜在的微胶囊用途，可以通过Bragg衍射波长或衍射颜色来监测胶囊内外的变化。

Colloidal crystals, three-dimensional periodic arrays of monodisperse particles, have received considerable attention with respect to the possible application, particularly as photonic crystals. The colloidal crystals are conventionally fabricated on the substrate, and the film shape limits the utility of these crystals for many applications. In this work, we have succeeded in fabricating colloidal crystals in various shapes such as shells, fibers, and large films by microfluidic techniques. We demonstrated that the gel-immobilized colloidal crystal shells are potentially useful for microcapsules that can monitor changes inside and outside the capsules through the Bragg diffraction wavelength or diffraction color.