3-Mercaptopropyltriethoxysilane is a chemical compound belonging to the organosilane group. Its chemical structure consists of a three-carbon chain with a thiol (-SH) group at one end and three ethoxy groups (CH₃CH₂O-) attached to a silicon atom at the other end. This structure makes it similar to 3-mercaptopropyltrimethoxysilane but with ethoxy groups (CH₃CH₂O-) instead of methoxy groups (OCH₃).

Like other organosilanes, 3-mercaptopropyltriethoxysilane is commonly used as a coupling agent and surface modifier in various industrial applications. Its primary function is to improve the adhesion and compatibility between organic materials (such as polymers) and inorganic materials (such as glass or metal surfaces). The ethoxy groups are hydrolyzable, meaning they can react with water to form silanol groups (Si-OH), which then condense to form strong bonds with surfaces.

Applications of 3-mercaptopropyltriethoxysilane include coatings, adhesives, sealants, and composites where enhanced adhesion, improved mechanical properties, and resistance to moisture and corrosion are desired.