Micelles of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) with blended polystyrene core and their application to the synthesis of hollow silica nanospheres

Core–shell–corona (CSC) micelles of asymmetric triblock copolymer, poly(styrene-b-2-vinylpyridine-b-ethylene oxide) (PS–PVP–PEO), containing polystyrene homopolymer (homo-PS) in the core were successfully prepared in aqueous media. The influence of homo-PS contents over the formation of the micelles was investigated thoroughly by various techniques such as dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence spectroscopy. It was found that the size of the PS core of the micelle was increased by the addition of homo-PS as observed by DLS and TEM techniques. The SEM and TEM measurements confirm the spherical morphology of the micelles and enlargement of PS core over the addition of homo-PS. The increase in the PS core volume of the PS–PVP–PEO micelles is attributed to the insertion of homo-PS in the PS core. The micelles have also been demonstrated as facile soft templates for synthesis of hollow silica nanospheres. The average diameter of the spherical hollow particles could be tuned between 30.6 and 38.8 nm with cavity sizes ranging from 20.7 to 28.5 nm using tetramethoxysilane as silica precursors under mild acidic conditions. The facile synthesis of hollow silica using the CSC micelles with different homo-PS contents indicates that the hollow void size can be controlled within a range of several nanometers.

Graphical abstractA judicious combination of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) and polystyrene homopolymer forms CSC micelles with a blended polystyrene core. The micelles prove to be useful for efficient fabrication of hollow silica nanospheres. The hollow cavity size can be tuned over several nanometers by simply controlling the polystyrene homopolymer contents.Figure optionsDownload full-size imageDownload high-quality image (54 K)Download as PowerPoint slideHighlights► Poly(styrene-b-2-vinylpyridine-b-ethylene-oxide) and polystyrene smoothly form micelles. ► The addition of polystyrene leads to enlargement of the core domain of the micelles. ► The micelles with blended polystyrene core have been utilized for tuning void size of hollow silica nanospheres. ► The hollow void size increases with the amount of polystyrene homopolymer contents. ► The micelles were thoroughly characterized by various techniques.