Thin Films of Semifluorinated Block Copolymers Prepared by ATRP

A symmetric diblock copolymer, poly(pentafluorostyrene‐b‐styrene) (PPFS‐b‐PS), is synthesized by atom transfer radical polymerization (ATRP). The behavior of PPFS‐b‐PS thin films on silicon wafers is investigated. Lamellar microdomains oriented parallel to the film surface are formed when the thin films are heated to 220 °C for 24 h, due to preferential interfacial interactions and the low surface energy of the PPFS. An electric field is used to overcome the low surface energy of the fluorinated block and preferential interactions with the substrate so as to force the lamellar microdomains to orient normal to the surface. Thin films of symmetric semifluorinated diblock copolymers form alternating layers due to preferential interfacial interactions and the low surface energy of the fluorinated block. Interference optical and atomic force microscopies and grazing incidence X‐ray scattering are used to characterize the morphology. An electric field forces the microdomains to orient normal to the surface.