Flow reactor syntheses of functional hybrid nanoparticles

Abstract

Monodispersed spherical particles have been claimed to be promising materials’ morphology for such applications as liquid crystal display spacer, photonic crystal, liquid chromatography stationary phase etc. depending on the size, composition and structure. Since the monodispersed spherical particles of silica and polystyrene in the size range of several hundreds of nm to microns are commercially available and also their syntheses are possible in the laboratory, their syntheses and applications have been published extensively. If the monodispersed porous spherical particles are available, one can extend the applications by means of host-guest chemistry. However, this type of materials is only available on surfactant templated nanoporous silicas. In this study, we examined the syntheses of nanoporous titania spherical particles. Titania possesses unique properties including high refractive index and UV absorption and photocatalytic abilities, therefore, monodispersed spherical particles may find applications where silica based nanoprorous silica spherical particles do not have an access. In the present study, we applied a microfluidic reaction to obtain well-defined titania based particles from titanium alkoxide and octadecylamine. Reactions occurred within micron sized channel have been known to show characteristic features such that temperature and concentration gradient are negligible, having potential to realize uniform reactions which directly correlate with the homogeneity of products. Nanoporous amorphous titanium dioxides with the surface area of 620m²･g^-1 and BJH pore size of 2.2 nm was obtained.