Silane coupling agents

Silane coupling agents are silicon-based chemicals that contain two types of reactivity–inorganic and organic–in the same molecule. A typical general structure is (RO)3SiCH2CH2CH2-X,where RO is a hydrolyzable group, such as methoxy, ethoxy, or acetoxy, and X is an organofunctional group, such as amino, methacryloxy, epoxy, etc.
A silane coupling agent will act at an interface between an inorganic substrate (such as glass, metal or mineral) and an organic material (such as an organic polymer, coating or adhesive) to bond, or couple, the two dissimilar materials.
A simplified picture of the coupling mechanism is shown in Figure 1.

(source:http://www.ac-chem.net/news/Silane-Coupling-Agents-9338.html)