Synthesis of silica hollow nanoparticles templated by polymeric micelle with core-shell-corona structure

The micelle of an ABC triblock copolymer having a core-shell-corona architecture was used as a template for the fabrication of a hollow silica nanosphere. Silica was deposited on a poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-PVP-PEO) micelle by the sol-gel method. At pH 4, the PVP block of the PS-PVP-PEO acts as an acid catalyst site for the hydrolysis of tetramethoxysilane (TMOS), while the PEO block of the micelle shows a weak interaction with the silanol groups of the inorganic polymer. Therefore, silica networks were mostly grown on the PVP block of the PS-PVP-PEO micelle in comparison to the PEO block. Hollow silica has almost the same diameter as that of the PS core of the PS-PVP-PEO neat micelle, and the thickness of the silica shell wall can be controlled by changing the relative concentration of TMOS with respect to the PVP block length of the micelle.