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The surface composition of styrene polymers capped at one or both ends by perfluoro groups has been determined by ISS, XPS, and static SIMS. The homopolymers, with M n 29 000−59 000, have an excess of the perfluoro end groups at the surface that is inversely proportional to the chain length and is commensurate with one or both ends having perfluoro groups. In contrast, double perfluoro end capped homopolymers of M n ∼9000 have only one of the perfluoro groups at the surface. In blends of perfluoro end capped styrene with hydrogen-terminated styrene, the fluorinated end cap causes the former to segregate to the surface. Nevertheless, the extents of segment segregation of single and double perfluoro end capped polymers of weights 29 000−59 000 are similar. For blends of perfluoro-capped polymer with M n 9000 in styrene of M n 30 000, the molecular weight and perfluoro end caps both strongly influence the segment segregation. The concentration of fluorine at the surface of all the blends may be estimated from the homopolymer XPS data and the blend monomer composition determined by static SIMS.

End capping a polystyrene with perfluorooctyldimethylchlorosilane is shown to strongly influence the surface segregation in blends of deuterated and hydrogenous polystyrenes. The surface composition, determined by static secondary ion mass spectroscopy, of a low molecular weight blend containing 0.14 mole fraction deuterated polystyrene, end capped by proton donation from methanol, was only slightly increased compared to the bulk value, even after annealing for several days at 150 °C. A low molecular weight blend containing the fluoro-end-capped deuteropolymer showed immediate surface segregation, which increased to give ca. 60% deuterated polymer at the surface after annealing. A similar blend, but with the fluoro end cap on the hydrogenous polymer, exhibited a surface enrichment of 41% of the hydrogenous component.Annealing a high molecular weight blend of hydrogenous and deuterated polystyrenes at 155 °C resulted in the gradual segregation of the deuterated component to the surface. A blend of high molecular weight fluoro-end-capped deuterostyrene and hydrogenous styrene showed an increased rate of segregation under the same conditions.

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