Porous nickel films plated in supercritical carbon dioxide emulsified electrolyte using a series of fluorinated nonionic surfactants

Thin porous Ni films were fabricated in supercritical CO2 (Sc-CO2) emulsion with a series of nonionic fluorinated surfactants, F(CF(CF3)CF2O)3CF(CF3)COO(CH2CH2O)nCH3 (denoted as PFP3-EOn where n = 1, 2 and 5). The film morphology and size distribution of pores were studied as a function of number of ethylene oxide groups and different concentrations of surfactants. Surfactant PFPO3-EO1 from low to medium concentrations showed a narrow size distribution of shallow pores on the films, and at high concentration it showed shallow pores and some large size deep pores. Surfactant PFPO3-EO2 at low concentration showed a narrow size distribution of shallow and deep pores on the film, and from medium to high concentrations the size distribution of deep pores increased. Compared to other surfactants, for all concentrations, surfactant PFPO3-EO5 showed a broad size distribution of deep pores, and it showed shallow pores only up to medium range of concentration. The increase of ethylene oxide groups and concentration of surfactants increased the size distribution of pores and decreased the number of pores on the films. There was a significant decline in the number of pores by the surfactant PFPO3-EO5. Sc-CO2 emulsion assisted Ni deposition using a series of nonionic fluorinated surfactants and concentrations shows great promise as a method to control porous structure on the plated films.