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Free keywords:
COLLOIDAL PHOTONIC CRYSTALS; SILICA NANOPARTICLES; OPTICAL-PROPERTIES; GROWTH; BANDGAP; OPALS; STEP
Abstract:
This paper presents a scalable method of preparing highly monodisperse core shell particles and hollow spheres, and their application in fabricating colloidal crystals. By using polystyrene (PS) particles as the template and vinyltrimethoxysilane as the precursor, the core-shell particles could be obtained via direct growth of vinyl-SiO2, hybrid material on the negatively charged PS template. This method has two interesting characteristics. The first is the tunable shell thickness (from 10 to 170 nm) combined with a low polydispersity (smaller than 3%). Second, the method is simpler than traditional ones, which use surface modified PS as template to get a uniform coating. Furthermore, the core-shell particles could be converted into hollow SiO2 spheres by removing the PS cores in a calcination process. Both the PS@vinyl-SiO2 particles and the hollow SiO2 spheres could be self-assembled into three-dimensional colloidal crystals, because the resulting particles are highly monodisperse and suspensible.
