ABSTRACT
Silanes that alter the chemical properties of surfaces have been studied intensively for over fifty years. In the context of coupling agents for polymer composites, biomolecule immobilization and adhesive technology, silanes have been both reviewed and have been the subject of many symposia. In contrast to silanes utilized as coupling agents in adhesive applications, silanes used to modify the surface energy or wettability of substrates under most conditions are not intended to impart chemical reactivity to the substrate. They are often referred to as non-functional silanes in order to indicate the absence of functional (reactive) groups on the organic substituent of the silane. Non-functional silanes are important since water adsorption at the interface is an important factor in coupling agent effectiveness. Although the use of non-functional silanes for surface modification is more pervasive than silanes used as coupling agents, they have been the subject of only a single review [1] which emphasizes hydrophobic surfaces. The full range of interactions of silane-treated surfaces with aqueous systems, from hydrophobic to hydrophilic, has not been reviewed. The objective of this overview is to demonstrate trends in behavior of substrates treated with non-functional silanes in aqueous environments by
providing examples of data from the literature on polar and non-polar substituted silanes and new data in which polar groups and non-polar groups are both present together as a single substituent on the silane.
