The effect of copolymer composition on the surface properties of perfluoroalkylethyl acrylates

The surface properties of two 9 perfluoroalkylethyl acrylic copolymers-aqueous, Zonyl (R) 329 and solvent-based, Zony (R) 225-were studied. Zony (R) 329 is a water-based dispersion and Zony (R) 225 a solvent-based copolymer solution; both polymers have the same perfluoroalkyethyl side chains [F(CF(2))(n)CH(2)CH(2)-] but have different comonomer compositions. Thin films, prepared by dip coating onto mica and quartz, with and without annealing, were characterized by contact angle and by X-ray photoelectron spectroscopy (XPS). The contact angle measurements showed little variation with polymer and with substrate, consistent with the supposition that the perfluoroalkylethyl chains aggregate on the surface and thus dominate surface properties, irrespective of the composition of the rest of the polymer. XPS revealed only small variations in surface chemistry for studied films. Annealed films showed improved segregation for solvent-based Zony (R) 225, which has both hydrocarbon alkyl and perfluoroalkylethyl side chains; the presence of hydrocarbon alkyl chains enables the perfluoroalkylethyl chains to reorganize after annealing. Depending on the external conditions, this thermal treatment can enable more perfluoroalkylethyl chains to reach the film surface (solid/air interface), leading to a reduction in the dispersive-dominant surface and enhancement in perfluoroalkylethyl segregation. This suggested that perfluoroalkylethyl side chains dominate the surface properties, which are thus not dependent on substrate, backbone composition, or formulation. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 4020-4,029, 200