A series of core/shell polystyrene/silica colloidal nanocomposite particles are synthesized by alcoholic dispersion polymerization of styrene in the presence of an ultrafine alcoholic silica sol.1 Hollow silica shells are formed on calcination of the polystyrene cores, as confirmed by TEM studies. On visual inspection in transmittance mode (illuminated background), the dry silica powders appear yellow to red in color, but when viewed in reflectance (dark background) relatively intense blue/green colors are observed. The latter phenomenon has been analyzed by visible reflectance spectroscopy and the reflectance maximum depends on the dimensions of the silica shell, which are in turn dictated by the initial nanocomposite particle diameter. SAXS is used to determine the packing density of the silica nanoparticles within the silica shell in both the original polystyrene/silica nanocomposite particles and also in the calcined silica shells. Combined with geometrical considerations, this allows the equivalent uniform silica shell thickness to be calculated for a particulate fused silica shell and related to recent theoretical predictions2for hollow particles comprising uniform contiguous silica shells.L. A. Fielding, O. O. Mykhaylyk, A. Schmid, D. Pontoni, S. P. Armes, and P. W. Fowler, Chem. Mater., 2014  , 26, 1270.M. Retsch, M. Schmelzeisen, H. J. Butt, E. L. Thomas, Nano Lett., 2011  , 11, 1389.

Visible Mie scattering from hollow silica particles with particulate shells

248th National Meeting (2014)

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