Surface-Initiated Ring-Opening Polymerization of L-lactide onto Hydroxy Terminated Surface Templates

The combination of patterning techniques, such as scanning probe based lithography, with the “grafting from” approach of polymer brushes opens the possibility to create structured functional substrates for the fabrication of sensors, electronic devices and others. The use of the surface-initiated ring-opening polymerization furthermore allows the introduction of biodegradable and technologically relevant polymer systems. These surface templates were obtained by the electro-oxidation of an n-octadecyltrichlorosilane coated silicon substrate and were subsequently functionalized with a second functional trichlorosilane, self-assembled onto the oxidized areas. A two step reaction sequence led to the formation of -OH functionalities. These hydroxy moieties served as covalently linked initiator templates for the ring-opening polymerization of L-lactide. Via this technique polymer brushes could be obtained with a height in the order of 30 nm. The created structures were further characterized by FT-IR and XPS spectroscopy as well as AFM microscopy.