title: Synthesis of Water-Based Dispersions of Polymer/TiO₂ Hybrid Nanospheres.
abstract: We develop a strategy for preparing water-based dispersions of polymer/TiO₂ nanospheres that can be used to form composite materials applicable in various fields. The formed hybrid nanospheres are monodisperse and possess a hierarchical structure. It starts with the primary TiO₂ nanoparticles of about 5 nm, which first assemble to nanoclusters of about 30 nm and then are integrated into monomer droplets. After emulsion polymerization, one obtains the water-based dispersions of polymer/TiO₂ nanospheres. To achieve universal size, it is necessary to have treatments with intense turbulent shear generated in a microchannel device at different stages. In addition, a procedure combining synergistic actions of steric and anionic surfactants has been designed to warrant the colloidal stability of the process. Since the formed polymer/TiO₂ nanospheres are stable aqueous dispersions, they can be easily mixed with TiO₂-free polymeric nanoparticle dispersions to form new dispersions, where TiO₂-containing nanospheres are homogeneously distributed in the dispersions at the nanoscale, thus leading to various applications. As an example, the proposed strategy has been applied to generate polystyrene/TiO₂ nanospheres of about 100 nm in diameter.
authors.affiliation: Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland. lu.jin@chem.ethz.ch.
authors.forename: Lu
authors.initials: L
authors.lastname: Jin
authors.affiliation: Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland. hua.wu@chem.ethz.ch.
authors.forename: Hua
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland. massimo.morbidelli@chem.ethz.ch.
authors.forename: Massimo
authors.initials: M
authors.lastname: Morbidelli
keywords: TiO2; hybrid; intense  turbulent shear; microchannel; mini-emulsion; nanocomposite