Sticky molecular surfaces: Epoxysilane self-assembled monolayers

Dense, homogeneous, and complete self-assembled monolayers with epoxy surfa ce groups were fabricated from epoxysilanes to serve as a template for chem ical anchoring of ultrathin polymer layers. We formed epoxysilane layers on silicon oxide surfaces of silicon wafers, and a combination of scanning pr obe microscopy, ellipsometry, XPS, and contact angle measurements was used to study their morphology and surface properties. A low concentration of ep oxysilane (less than 0.5 vol %) led to significant aggregate formation caus ed by a prevailing hydrolization/polymerization of epoxysilane molecules in bulk solution. Epoxysilane SAMs prepared from 1% solution were truly monom olecular films with a virtually normal molecular orientation of densely pac ked molecules, which were firmly attached to the substrate. Self-assembly d eposition of epoxysilanes at optimal conditions resulted in the formation o f homogeneous SAMs 0.85 +/- 0.2 nm thick with the surface roughness 0.22 +/ - 0.05 mm.