The surface characteristics of polystyrene-films having various fluoroalkylated ratios (Rf-ratio) were studied by contact angle and Electron Spectroscopy for Chemical Analysis (ESCA) measurements. The fluoroalkylation agents used were perfluoroalkanoyl peroxides [bis (heptafluorobutyryl) peroxides]. Critical surface tension (γc) of the polystyrene films decreased with increase in Rf-ratio, but remained constant above an Rf-ratio of 26%. Decrease in γc was found due to that in the London dispersion force (γcd) and polar force (γcp) in the components of γc. The effects of fluorine atoms in fluoroalkyl groups on surface characteristics (water-repellent and oil-repellent) of polystyrene were maximized even when the atoms were relatively few in number.
