Nanoscale Pattern Formation in Langmuir−Blodgett Films of a Semifluorinated Alkane and a Polystyrene−Poly(Ethylene Oxide) Diblock Copolymer

A novel example of the self-assembling capabilities of semifluorinated n-alkanes is presented:  nanoscale periodic structures were revealed in mixed Langmuir−Blodgett films of a semifluorinated n-alkane with a polystyrene−poly(ethylene oxide) diblock copolymer by atomic force microscopy. The surface structures, resembling honeycombs with a hump at the center, have a periodicity of ∼40 nm. The same qualitative morphological features were found in all mixed films, independently of the polymer grafting density. Evidence suggests these structures arise from the organization of the semifluorinated alkane molecules segregated to the surface of the polymer layer.