Solution properties of partially fluorinated unsaturated esters and surface properties of polyester coatings containing partially fluorinated unsaturated esters as cross-linkers

Simple, reactive amphiphilic molecules were prepared by condensation of perfluorooctylethyl alcohol with elaidic, oleic, and linoleic acids. The fluorinated, unsaturated esters were found to be surface active in polyester and urethane-modified alkyd coatings. In addition, they function much like typical drying ails used in these coatings through oxidative cross-linking. The surfaces of the coatings were examined by contact angle goniometry and X-ray photoelectron and time-of-flight secondary ion mass spectroscopy. The solution properties of these fluorinated derivatives were studied by measurement of surface tension isotherms, vapor pressure osmometry, and variable temperature F-19 NMR spectroscopy in n-butyl acetate solution. Analysis of the data revealed that aggregation is occurring at low ( < 10(-1) mol/L) solute concentration. The aggregates were small and ranged between 3 and 7 monomer units. Analysis of the variable temperature F-19 NMR data for the linoleic acid ester gave thermodynamic parameters for aggregation of Delta G(a)degrees approximate to -4.30 +/- 0.2 kcal/mol, Delta H(a)degrees approximate to 6.11 +/- 2 cal/mol, and Delta S(a)degrees approximate to 15.7 +/- 0.8 cal/(mol.K).