PDMS-SiO2 hybrid materials – A new insight into the role of Ti and Zr as additives

The last two decades have seen a remarkable growth in the design of new hybrid materials applied to different areas, from photonics to biomaterials, together with new coating materials with self-cleaning features. Among the various systems studied, the PDMS-SiO2 system remains as a good basis for further developments by adding other compounds such as transition metals. In this work, a detailed study of the influence of titanium or zirconium in the chemical structure and final microstructure of such hybrids was made. It was concluded that, due to the lower reactivity of the titanium alkoxide during the sol–gel preparation process, titanium is preferably located on the surface of secondary particles of silica, unlike the zirconium, which being more reactive, positions on the surface of the primary particles. This difference leads to xerogels with dissimilar characteristics and morphologies.