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

Effect of deaeration on the adsorption of a mixture of cetyltrimethylammonium bromide and cetyldimethylbenzylammonium chloride at the mercury/electrolyte solution interface

“…The effect of deaeration is less pronounced compared to our previous paper [11] where we studied single surfactants, where a complete inhibition of the formation of the film was observed. In this case, a complete inhibition of the film formation is not observed, indicating that using the mixtures of surfactants the condensed film that is formed more easily and is more stable.…”

“…From the above noted figures we conclude that deaeration results in a change in the kinetics of not only the film formation as was found in [11] but also in the kinetics of the adsorption of the surfactant molecules at the interface at potentials where no condensed film is formed.…”

“…We then studied the change of the capacitance with time, following potential jumps from −0.25 V, i.e., the potential where the surfactants are not adsorbed, to the whole potential range, i.e., from −0.25 to −0.90 V, with a step of 0.01 V. The capacitance transients were recorded at 5 • C. We made these measurements at 5 • C instead of 2 • C, where according to our previous paper [11] a condensed film was formed in a whole potential range. The reason was that at this low temperature the deaeration after less than 20 min resulted in precipitation phenomena.…”

“…The adsorption of binary mixtures of cetyltrimethylammonium bromide (CTAB) and cetyldimethylbenzylammonium chloride (CDBACl) at the mercury/electrolyte interface was studied in various electrolyte systems [11]. The optimum conditions for a condensed film to form at as wide a potential range as possible were found to be 2 × 10 −4 M CTAB and 2 × 10 −4 M CDBACl in 0.07 M KF and 0.03 M KBr at 2 • C. It was found that in that system the condensed film was formed in the whole potential range from −0.4 to −1.9 V vs Ag/AgCl, in less than 220 s.…”