Functionalizacion of epoxy-based networks by the preferential surface enrichment of perfluorinated tails to achieve hydrophobic surface is described. The selected fluorinated epoxies (FE) were: 2,2,3,3,4,4,5,5,6,6,7, 7,8,9,9,9-hexadecafluoro-8-trifluoromethyl nonyloxirane (FED3) and 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluoro nonyloxirane (FES3). Two series of crosslinked fluorinated epoxy-based materials containing variable fluorine contents (from 0 to 5 wt % F) were prepared using formulations based on partially fluorinated diamine, epoxy monomer and a curing agent. The epoxy monomer was based on diglycidyl ether of bisphenol A (DGEBA) while the curing agents were either propyleneoxide diamine (JEFFAMINE) or 4,4'-methylenebis(3-chloro 2,6-diethylaniline) (MCDEA). It was found that depending on the curing agent employed, homogeneous distribution of fluorine or phase separation distinguishable at micrometer or nano-meter scale was obtained when curing blends initially homogeneous. The morphology and composition of partially fluorinated networks were investigated on a micrometer scale combining scanning electron microscopy and X-ray analysis. When curing with JEFFAMINE, samples were homogeneous for all fluorine proportions. In contrast, MCDEA-cured blends showed fluorine-rich zones dispersed in a continuous epoxy-rich phase. A completely different morphology, characterized by a distribution of irregular fluorine-rich domains dispersed in an epoxy-rich phase, was obtained when curing blends initially immiscible. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 608-616, 2011