Controllable surface morphology is requisite across a gamut of processes, industries, and applications. The surface morphology of silica-coated polystyrene microspheres was controllably modified to enable generation of smooth or bumpy, raspberry-like surfaces. Silica shells were deposited via the sol-gel process (using tetraethyl orthosilicate as the silica precursor) onto 1-2 micrometer diameter anionic polystyrene spheres, fabricated by emulsifier-free polymerization. By varying the concentration of the silica precursor and ammonium hydroxide base-catalyst, and altering electrostatic surface interactions through the addition of a cationic polymeric brush, an array of surface topologies were generated. The resulting silica shells ranged from 100-200 nm in thickness as measured by calcination of the polystyrene template. Finally, we also used previously published empirical relations between reaction conditions and resulting silica colloid diameter to control the shell topology. Smooth and raspberry-like silica shells on polystyrene templates have been demonstrated extensively, however, to the authors’ knowledge, this is the first instance in which radical changes in surface morphology may be obtained from a single polystyrene template coated in silica using readily available materials and facile sol-gel reaction processes. This work may serve as a guide to generate a versatile platform for research in the multitude of applications that utilize polystyrene-silica core-shell particles.

Topological control of polystyrene-silica core-shell microspheres

254th National Meeting (2017)

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