Effect of Poly(vinyl pyrrolidone) Concentration on the Preparation of Polystyrene/TiO2 Core-Shell Particles

Monodisperse submicron-sized PS/PVP/TiO2 core-shell hybrid particles with controllable shell thickness were prepared via in-situ sol-gel method in the presence of PVP stabilizer. Depending on the PVP concentration, 3 different types of shapes and sizes of the resulting PS/PVP/TiO2 core-shell particles are reported. The experimental observation indicates the use of proper amount of PVP is the most important factor in making uniform PS/PVP/TiO2 core-shell particles with dense coatings and smooth surfaces. By adjusting the concentration of PVP, the densities and refractive indices of the PS/PVP/TiO2 core-shell particles could be controlled from 1.6 to 3.1 g/cm(3) and from 1.66 to 1.81, respectively. High refractive indices and low densities of the PS/PVP/TiO2 core-shell particles prepared in the work could be used for the study in photonic crystals and electrophoretic displays.