Synthesis and Characterization of Oleophobic Fluorinated Polyester Films

The study presented in this dissertation is dedicated to the synthesis and characterization of oleophobic fluorinated polyester films. Specifically, the blending of oleophilic polyethylene terephthalate (PET) with low surface energy materials such as fluorinated polyesters has been used in order to fabricate oleophobic PET films. First, fluorinated polyesters (P(PF-oate-R)) possessing different end-groups (-COOH, -OH and -CF3) are synthesized via polycondensation reaction of isophthaloyl chloride with perfluoro ether alcohols. Then, they are solvent-blended with PET at various concentrations to obtain oleophobic polyester films of different compositions. In addition, the films are annealed to investigate the effect of annealing on surface properties of the films. The results show that the obtained PET/P(PF-oate-R) polyester films demonstrate low wettability that depended on the polyester end-groups, film compositions, and annealing. It is found that PET blended with fluorinated polyesters terminated with CF3 groups exhibit higher contact angle (CA) with water and oils than other polyesters. In addition, CA increases with increasing P(PF-oate-R) polyester content in blends. To facilitate the oleophobicity of PET films, the fluorinated polyesters terminated with -CF3 groups with two different Mw were synthesized and blended with PET. The results reveal that at low concentrations, low molecular weight polyesters migrate to the surface easily, resulting in higher surface coverage. Thus, it leads to higher water and oil repellency. On the other hand, when they are used at high concentrations, higher molecular weight polyesters in blends reduce the wettability of the surface to the higher level. It is found that the wettability of the PET film surface depends on not only the Mw of polyesters, but also on annealing protocol. To this end, the effects of the annealing temperature on surface wettability are also examined