Condensed film formation of binary mixtures of cetyltrimethylammonium bromide and cetyldimethylbenzylammonium chloride in a wide potential region at the mercury/electrolyte interface

The adsorption of binary mixtures of cetyltrimethylammonium bromide (CTAB) and cetyldimethylbenzylammonium chloride (CDBACl) at the mercury/electrolyte interface was studied in various electrolyte systems. The optimum surfactant concentration and electrolyte ratio was searched for, to obtain the formation of a condensed film at as wide a potential range as possible at the highest temperature possible. The optimum conditions found were 2×10−4 M2×10−4 M CTAB and 2×10−4 M2×10−4 M CDBACl in 0.07 M KF and 0.03 M KBr at 2 °C. The capacitances vs time curves were used for the reconstruction of isochronous capacitance vs potential curves. These curves showed that in that system the condensed film was formed in the potential range from −0.4 to −1.9 V vs Ag/AgCl in less than 220 s. The stability of this film, following the removal of the mercury drop from the solution, was also studied.

The curves show that in the selected system at 2 °C the condensed film is formed in a wide potential range from −0.4 to −1.9 V vs Ag/AgCl, in less than 220 s.Figure optionsDownload as PowerPoint slide