Smart tailoring of the surface chemistry in GPTMS hybrid organic-inorganic films

Hybrid films prepared from 3-glycidoxypropyltrimethoxysilane have been widely used as organic–inorganic materials for several applications. Tailoring the coating surface should disclose new possibilities of applications in biomaterials as functional interfaces for cells and enzymes. In this work we have designed the synthesis of 3-glycidoxypropyltrimethoxysilane hybrid films to modify the surface properties without additional surface functionalization steps. The pH of the precursor sols has been changed from highly basic to acidic and neutral pH and then the sols have been used to deposit highly transparent films. The analysis by infrared spectroscopy has shown that the synthetic conditions allow tuning the degree of condensation of the silica network and the percentage of epoxide ring opening. A precise control of these two parameters enables the formation of a smart surface library where hydroxyl or epoxide groups or the mixed presence of both change the hydrophobicity of the surface and thus its capability of binding molecules and nano-objects.