2.3.1. Synthesis of Hollow Silica Tadpole-like Nanomaterials.
Monodispersed hollow silica tadpole-like nanomaterials were
prepared by using 1-propanol as the solvent. A mixture of 3.00 g of
PVP and 30.00 mL of 1-propanol was sonicated for 30 min until all
PVP was dissolved. An aliquot of 3.00 mL of 95% EtOH, 0.84 mL of
H2O, and 0.20 mL of 0.17 M Na3Ct was added into the PVP/1-
propanol mixture and gently shaken by hand, followed by the addition
of 0.30 mL of TEOS and 0.60 mL of NH4OH. The mixture was left to
rest, and the reaction was allowed to proceed overnight at room
temperature. The tadpole-like nanomaterials were collected by
centrifuging at 3000 rpm for 30 min. The supernatant was removed,
and the precipitates were washed three times with EtOH for 20 min at
a centrifuging speed of 3000 rpm