Polypentafluorostyrene (PPFS) (M (w) = 1.7 x 10(5) Da, M (w) /M (n) = 1.6, and D cent (g) = 110A degrees D) has been synthesized by radical polymerization of pentafluorostyrene. The chemical structure of the polymer has been confirmed by H-1 and F-19 NMR data. The permeability and diffusion coefficients of gases (He, H-2, O-2, N-2, CO2, and CH4) have been measured on a barometric setup. The permeability, diffusion, and solubility coefficients of gases have been shown to increase with the increases in the fluorine content in the repeat unit of the polymer in the polystyrene-poly(p-fluorostyrene)-PPFS series. Such behavior of transport parameters in the polymer series is associated with the growth in the fractional free volume and decrease in the cohesive energy density. The investigated polymers on the basis of styrene and its derivatives including PPFS are located in the middle of clouds of Robeson diagrams for N-2/CH4, CO2/CH4, and O-2/N-2 and are not of interest for their separation.