Formation of Hierarchical Structure in Microspheres Fabricated with Microfluidic Method based on Homopolymer Blend

Recently, particles of polymer composites including polymer-polymer blends and hybrids with inorganic materials with various functionalities have been applied to biomedical fields [1], optical devices [2], and so on. The particles of polymer composites have been prepared by several techniques. Especially, a microfluidic device has received considerable attention because of the simple procedure to fabricate multiple-phase emulsions utilizing the laminar flow inside narrow capillaries, and multiple phases can be formed in the interiors of the emulsion droplets, resulting in the formation of multi-phased polymer microspheres [3, 4]. Nisisako et al. reported that a microfluidic system which involves a binary mixture of monomer droplets containing different pigments produces the polymer particles of Janus types [5]. In contrast, the approaches using the self-assembly of multi-components, i.e., the phase separation of polymers, can also afford microspheres with internal and surface nanostructures. Nanostructured microspheres exhibit a potential for applications in the next generation such as the optical and photonic 【Transaction】