Photoreactive self assembled monolayers for tuning the surface polarity

In this contribution the modification of gold surfaces by self assembled monolayers (SAMs) of the photoreactive compound 11-mercaptoundecanoic acid, phenyl ester (MUAP) is presented. Upon irradiation with UV-light (λ = 254 nm) the phenyl ester groups photoisomerize to give hydroxyketones (photo-Fries reaction). Due to the formation of polar hydroxy groups the surface tension of the SAMs changes. The photogenerated hydroxyl groups were selectively modified with perfluorobutyryl chloride. This postexposure modification led to a significant change in wetting behaviour and surface energy and XPS indicates that patterning is possible.