On the surface properties of waterborne fluorinated coating polymers

Full Paper: In the present work the results of a study concerning the surface properties of coating materials obtained from fluorinated latices are reported. Better understanding is required regarding the influence of polymer structure, latex composition, and morphology on the surface properties of the resulting films. For this purpose, two commercial fluorinated waterborne polymer dispersions were compared with a model fluorinated acrylic latex purposely synthesized. The surface properties of mold samples, prepared from either the whole solid matter contained in the latices (dried latex) or the purified polymer, were determined by simple contract angle measurements. Two series of homologous liquids, namely H-bonding alcohols and apolar hydrocarbons, were employed for determining the critical surface tension gamma(c) according to the method of Zisman. The results of the surface characterization indicate that the degree of fluorination plays a minor role in these materials, suggesting that the threshold above which the polymer surface is virtually saturated by CF2 or CF3 groups might have been largely exceeded. On the other hand, the effectiveness of the hydrophobic fluorinated coating resulted substantially unaffected by the presence of amphiphilic low molecular weight additives, such as surfactants and wetting agents, which can actually contribute to the reduction of the surface energy of these materials upon suitable thermal treatment.