Grafting characterization of thin organosilane films on silica substrate

Silanes are widely used as coupling agents favouring the adhesion of organic polymers to an inorganic surface. As a model system for the composite interface, we have used grafted n‐alkylsilane on various silica substrates. Contact angles by the sessile drop method were measured as a function of varying alkyl chain lengths, chemical structure and deposition conditions. We found that the silanization of surfaces involved the reaction of monofunctional alkyl‐silanes with surface hydroxyl groups, through which organic moieties were covalently bonded resulting in a single monolayer. Modified surfaces showed a high contact angle with water and a low non dispersive component of surface energy as olefinic surfaces. The wetting of these monolayers was found to be slightly dependent on the chain length. Silane films adsorbed from solution showed wetting properties reflected the insertion of solvent between the grafted molecules. Surface coverage determined by 29Si NMR as a function of chain length indicated that th...