Optimized Thermal Treatment for Preparation of Double Inverse Opals Incorporating Movable Cores

Abstract

A combination of the co-assembling process to fabricate binary colloidal crystals (BCCs) and the successive heat treatment to selectively remove the polymer component from the BCCs was conducted to create double inverse opals (DIOs) in which a movable sphere was embedded within each inorganic compartment of nanoparticles. Micron-sized silica cores coated with polystyrene shell and silica nanoparticles were used as the BCC components in the co-assembling process. According to the residue pro le measured in thermogravimetric analysis, the heat treatment at low temperatures of 250, 300 and 350°C was conducted to nd a cost-e ective process, resulting in nding that 300°C heating for 7 h was suitable for obtaining the high movability of micron-sized cores in the compartment. Application of 1 kHz electric eld at strength higher than 100 V/mm could suppress the random motion of cores in a wet-state DIO.

Highly Reflective and Transparent Shell-Index-Matched Colloidal Crystals of Core–Shell Particles for Stacked RGB Films

“…In the future, we envision that these layers can be tuned independently to create all different colors within the same film. In particular, we envision hollow structures, such as double-inverse opals − or assembled yolk–shell particles, − in which the location of the core particle can be controlled by external fields , to manipulate the reflection intensity of each layer. Especially, when this switching can be performed at a millisecond time scale, these structures will have great potential as reflective displays.…”

Double-Inverse-Opal-Structured Particle Assembly as a Novel Immobilized Photocatalytic Material

“…In this study, a double-inverse-opal (DIO) photocatalytic structure is proposed as a novel, immobilized-type photocatalyst system. The DIO structure [27][28][29] consists of periodically ordered macropores containing a single particle within the macropore framework. The DIO is a hierarchically structured material developed as an advanced inverse opal that is applicable to separation materials and photonic crystals [30,31].…”