Spontaneous Preparation of Monodispersed, Structural Colored, Spherical Particles by Rotational Stirring

Abstract

When rotational stirring was applied to an electrically neutral aqueous suspension containing negatively charged, monodispersed silica fine particles and a positively charged polyelectrolyte, monodispersed, spherical particles with a size of several hundred micrometers were obtained. Conditions such as the rotational stirring speed, solute concentration, and total suspension amount were examined to clarify the conditions under which the monodispersed, spherical particles can be obtained. Spherical particles with a uniform size were obtained because the solutes create aggregates by electrostatic interactions, and the flow of the suspension from rotational agitation disperses the aggregates. Additionally, the obtained monodispersed, spherical particles contained monodispersed silica fine particles in submicron size aggregates with short-range order. We found that monodispersed, spherical particles with a vivid structural color could be prepared by incorporating a small amount of a black substance in the spherical particles. Because monodispersed, spherical particles with various colors can be created using silica, polymer, and carbon, which are non-toxic materials, they may be useful as new, environmentally safe pigments.[a] M. Scheme 1. A schematic diagram of the method for preparing monodispersed particles by rotational stirring of an aqueous suspension containing monodispersed silica fine particles and PDDA.

Progress in polydopamine-based melanin mimetic materials for structural color generation

“…A spherical photonic material with a three-dimensional structure constructed from colloidal particles is expected to have use as a structurally colored pigment, and many attempts have been made to achieve this application [104][105][106][107][108]. Our group demonstrated the fabrication of spherical photonic materials by the membrane emulsification method, utilizing the property that PS@PDA particles were well dispersed in water [109].…”