Synthesis and characterization of a polystyrene-type polymer bearing a cyclic perfluoroalkylene group

Perfluoroalkyl-containing aromatic compounds are predicted to have fascinating material properties. In this work, a styrene derivative bearing a cyclic perfluoroalkylene group, –(CF₂)₄–, was synthesized and polymerized to afford the corresponding polymer. The styrene derivative was obtained via the Ullmann coupling of I–(CF₂)₄–I with 3′-bromo-4′-iodoacetophenone, NaBH₄ reduction of the ketone moiety, and dehydration using P₄O₁₀. Free-radical polymerization (FRP) of the styrene derivative afforded polymer with number-average molecular weight (M_n) and dispersity index (DI) of 1.1 × 10⁴ and 3.1, respectively. The thermal stability of the synthesized polymer (T_d10% 359 °C, T_g 149 °C) was greater than the previously reported n-C₄F₉-substituted polystyrene (T_d10% 296 °C, T_g 19 °C). The increased thermal stability of the newly synthesized polymer is hypothesized to arise from the lack of terminal CF₃ moieties. The cyclic perfluoroalkylene-substituted polystyrene exhibited hydro- and oleo-phobicities comparable to those of the n-C₄F₉-substituted polystyrene, suggesting that the introduction of cyclic perfluoroalkylene groups instead of the commonly used R_f groups may have the potential to develop thermo-resistant polymers with hydro- and lipo-phobicity. Thew newly synthesized polymer is suitable for a variety of applications requiring high-T_g optical polymeric materials.