The effect of a fluorinated sodium bis(2-ethylhexyl) sulfosuccinate (aerosol-OT, AOT) analogue surfactant
(sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate) on the interfacial layer of
supercritical CO2 + water and supercritical CO2 + Ni-plating solution systems was investigated by
measuring via the capillary rise method. These interfacial tensions were measured in the pressure range
of (0.1 to 20.0) MPa at multiple temperatures for each of five interfaces: (1) CO2 + water system at
(293.15, 298.15, 311.15, and 344.15) K; (2) CO2 + Ni-plating solution system at (313.15, 328.15, and
344.15) K; (3) CO2 + Ni-plating solution + F-AOT surfactant (0.1 and 0.3 mass %) system at (313.15,
328.15, and 344.15) K; (4) CO2 + Ni-plating solution + ethanol (10 and 20 vol %) system at 328.15 K; and
(5) CO2 + Ni-plating solution + F-AOT surfactant (0.1 mass %) + ethanol (10 vol %) system at (313.15,
328.15, and 344.15) K. The reliability of the apparatus was confirmed by comparing the experimental
data with literature data for the CO2 + water system at (311.15 and 344.15) K. The individual addition
of the F-AOT surfactant and ethanol reduced the interfacial tension for the CO2 + Ni-plating solution
system; however, the simultaneous addition of these two substances caused the opposite effect on the
interfacial tension.