Photochemical studies of (aminoethylaminomethyl)phenethyltrimethoxysilane self-assembled monolayer films

The deep UV (193 nm) photochemistry of the self-assembled monolayer film PEDA, H2NCH2CH2NHCH2C6H4CH2CH2Si(OCH3)(3), has been studied on Si and SiO2 surfaces using UV and X-ray photoelectron spectroscopies, contact angle goniometry, and laser-desorption Fourier transform mass spectrometry. Mechanistic studies show that Si-C cleavage is the ultimate photochemical pathway; however, interpretation of the photochemical data is complicated by formation of a surface-bound intermediate, as well as adsorption of photoproducts to the substrate surface. Treatment of the exposed film with high ionic strength aqueous solutions is found to remove the adsorbed material. Patterned 193 nm exposure of PEDA SAM films on SiO2 produces a surface template of reactive amine groups at relatively low doses (similar to 400 mi cm(-2)), which can be used for selective, high-resolution attachment or deposition of materials on the unexposed regions of the film.