Oscillatory Electrodeposition and Formation of Alloy Multilayers Induced by a Phase Transition of Adsorbed Surfactants at the Electrode Surface
電極表面上の吸着界面活性剤の相転移に誘起される振動電析反応と合金多層膜の形成

Shuji NAKANISHI, Sho-ichiro SAKAI, Tomoyuki NAGAI, Yoshihiro NAKATO
2006 Hyomen Kagaku  
The electrodeposition reaction in an acidic solution containing Cu 2 and Sn 2 shows, in the presence of a cationic surfactant, a negative differential resistance (NDR) and a current oscillation in a potential region where SnCu alloy is deposited. Depth profiles obtained by Auger electron spectroscopy (AES) have indicated that alloy films deposited during the oscillation have a structure of nano-period multilayers composed of alloys of different compositions. Detailed investigations have
more » ... that the NDR arises from adsorption of a cationic surfactant (acting as an inhibitor for diffusion of Cu 2 and Sn 2 ions) on the electrode (alloy) surface and the oscillation comes from coupling of the NDR with the ohmic drop in the electrolyte. A notable point is that the NDR appears in a very narrow region of the potential (of about 5 mV or less). This fact strongly suggests that the NDR (and the oscillation) arise from a sudden structural change in an adsorbed surfactant layer such as a phase transition from a gaseous adsorbed layer to a condensed liquid-like one. This conclusion was supported by the experiments on effects of the concentration and the chain length of the surfactant on the NDR.
doi:10.1380/jsssj.27.408 fatcat:dr7cajxhvfe73gfuvc2cergilq