Structure and Bottom-up Formation Mechanism of Multisheet Silica-Based Nanoparticles Formed in an Epoxy Matrix through an <i>In Situ</i> Process
F. Branda, Aurelio Bifulco, Dieter Jehnichen, Dambarudhar Parida, Robin Pauer, Jessica Passaro, Sabyasachi Gaan, Doris Pospiech, Massimo Durante
Abstract
" sol-gel procedure starting from two precursors: tetraethyl orthosilicate (TEOS) and 3-aminopropyl-triethoxysilane (APTES). APTES also played the role of a coupling agent. The use of advanced techniques (bright-field high-resolution transmission electron microscopy, HRTEM, and combined small- and wide-angle X-ray scattering (SAXS/WAXS) performed by means of a multirange device Ganesha 300 XL+) allowed us to evidence a multisheet structure of the nanoparticles instead of the gel one typically obtained through a sol-gel route. A mechanism combining in a new manner well-assessed knowledge regarding sol-gel chemistry, emulsion formation, and Ostwald ripening allowed us to give an explanation for the formation of the observed lamellar nanoparticles.