The phase behavior of mixtures of water, hexafluoropropylene (HFP), ammonium perfluorooctanoate (C8), fluorinated alcohol, and ammonium chloride is reported as a function of temperature, pressure, electrolyte concentration, and hydrophobicity of the surfactant blend. The addition of aa short-chain alcohol, hexafluoro-2-methyl-2-propanol, to the water -HFP-C8 mixture promotes formation of microemulsion phases. Replacing the weak amphiphile with a medium-chain alcohol, for example, 2-perfluorobutyl-2-propanol or 2-perfluorohexyl-2-propanol, produces large liquid crystalline regions. Microemulsion formulations containing the fluorinated olefin in a near-critical state along with water, fluorinated surfactant, fluorinated alcohol, and salt follow the generic patterns of phase behavior common for conventional liquid mixtures as a function of experimental variables. Pressure has a strong effect on the phase behavior when one of the components is compressible.