Surfaces of Semi-Fluorinated Block Copolymers Studied Using Nexafs

Abstract
The molecular orientation within a surface liquid crystalline layer made up of semifluorinated side-groups [-CO-(CH2)x−x-(CF2)yF] (SF groups) attached to the isoprene block of a styrene-isoprene diblock copolymer was determined by analyzing the partial electron yield Cedge NEXAFS signal. The results show that in contrast to the bulk, where the SF groups lie parallel to the diblock copolymer lamellae and thus parallel to the surface, the surface SF groups make an average angle with the surface normal of between 29 and 46° depending on x and y.