A series of fluorinated analogues of AOT, the sodium salt of bis(3,3,4,4,5,5,6,5,7,7,8,8,8-tridecafluorooctyl)-2-sulfosuccinate (CF3(CF2)5CH2CH2OOCCH2CH(SO3Na)COOCH2CH2(CF2)5CF3, di-HCF7),the sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentyl)-2-sulfosuccinate (H(CF2)4CH2OOCCH2CH-(SO3Na)COOCH2(CF2)4H, di-HCF4), and the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)-2-sulfosuccinate(CF3CHFCF2CH2OOCCH2CH(SO3Na)COOCH2CF2CHFCF3, di-HCF3), were synthesized and characterized by 1HNMR. The pressure-temperature phase diagrams for W/CO2 microemulsions stabilized by the three surfactants were determined. At a fixed temperature, cloud point pressures increased with increasing water-to-surfactant ratio. The water solubilization capacity increased in the order di-HCF4 > di-HCF3 > di-HCF7.