High reflective efficiency and durability of multilayered core-shell composite particles with controlled shell thickness

Multilayered core-shell composite particles with a high reflective efficiency and durability were prepared by a subsequent formation of multilayered shells on silver-coated iron (Fe/Ag) microspheres. The SiO2 and TiO2 multilayered shells were formed onto the Fe/Ag microspheres by the sol-gel reaction of tetraethylorthosilicate (TEOS) and titanium n-butoxide (TBOT), respectively. The thickness uniformity of SiO2 and TiO2 shells was improved by ultrasonication during the sol-gel reaction process. The mechanical durability of the composite particles was also investigated by an ink grinder. The SiO2 and TiO2 multilayered shells showed high efficiency for preserving the reflectivity and increasing the durability of the Fe/Ag microspheres.