Surface immobilization of functional molecules by reactive self-assembling

Self-assembled monolayers (SAMs), combined with the lithography, were employed to fabricate functional surfaces. A new strategy in SAM technology, by using reiterated micro contact printing process, was proposed to produce a multi-level fluorescent TAG (multi-TAG), which consists of two overlapping micrometric patterns, made of a fluorescent oligothiophene SAM bonded with a Si/3-aminopropylthriethoxysilane substrate. The samples were characterized by fluorescence microscopy, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). In particular, the process of chemical interaction occurring during the self-assembling was investigated. The obtained results showed that the SAM process occurred with the amidic bond formation. Moreover, the grazing-angle XPS measurements indicated that the horizontal arrangement of oligothiophene molecules on the substrate surface was preferred.