Polystyrene-Polyperfluorooctylethyl acrylate Diblock Copolymers: The Effect of Dilution of the Fluorinated Mesogenic Chains on Bulk and Surface Properties

Three smectic poly(styrene-b-perfluorooctylethyl acrylate) block copolymers (S-b-AF8) with different degrees of polymerization (n, m) of the relative blocks were synthesized by atom transfer radical polymerization (S, n=25; AF8 m=2, 6, 23). The mesophase structure and transition temperatures were investigated by DSC and WAXD. The block copolymer having the shortest fluorinated block was blended with a thermoplastic elastomer SEBS in different proportions, in order to look at the effect of a further dilution of the perfluorinated groups on non-wetting properties. Thin films of the block copolymers as well as the blends exhibited large contact angles with both water and n-hexadecane, which resulted in low solid surface tensions. XPS findings at different photoemission angles confirmed the effective surface segregation of the mesogenic chains of the fluorinated polymer block