Surface Attachment and Stability of Cross-Linked Poly(ethylenimine) - EpoxyNetworks on Gold

摘要

The formation of thin films of 3-glycidoxypropyltrimethoxysilane (GPS) on goldwas studied by reflection-absorption infrared spectroscopy (RAIR) and optical ellipsometry. Mass changes on the surface were measured with the quartz crystal microbalance (QCM). Thin films of poly(ethylenimine) (PEI) were formed on these modified gold surfaces and cross-linked with the diepoxy compound EPON (bisphenol A/epichlorohydrin epoxy resin). The resulting films are reactive toward HSiClMe2. The expected substitution of chloride at the silicon center is observed, showing that amino and/or oxo ligands are available on the surface. The stability of the PEI/EPON films in water at different pH and temperatures was studied by electrochemical methods and compared to that of monolayers of octadecylmercaptan (ODM) and octadecyltrichlorosilane (OTS). ODM on gold is quite stable at neutral and basic pH in aqueous solution up to 100 deg C. Films of PEI, covalently bonded to the GPS layer and cross-linked with EPON, are extremely durable. jg p.2.