series, Sakai Chemical Industry Co., Ltd. (Sakai, Japan)) were used
as received as core particles. The average diameter of the silica
core particles (Dcore) was 451 nm. The
coefficient of variation of diameters (CV), which is commonly used to evaluate the monodispersity of particles,
was 4.9%. Sodium bromide (NaBr, 99.9%), tetraethyl orthosilicate (TEOS,
95%), cetyltrimethylammonium bromide (CTAB, 98%), ammonia aqueous
solution (NH3, 25%), and ethanol (99.5%) were purchased
from FUJIFILM Wako Pure Chemical Corporation (Osaka, Japan). Deionized
water (>18.2 MΩ·cm) was prepared by Direct-Q3 UV (Merck
KGaA; Darmstadt, Germany).