含CTAB-苦味酸的水/油/水体系的液膜振荡规律

Oscillation of liquid membrane of water/oil/water system containing CTAB and picric acid

研究了水(CTAB-正丁醇水溶液)/油(含苦味酸的硝基苯溶液)/水(葡萄糖水溶液)体系的液膜振荡。通过改变CTAB的浓度、苦味酸等协同物的浓度研究了振荡曲线的变化规律。研究显示,CTAB浓度在3mmol.L-1以上才有振荡,随着浓度的增加,振荡频率变小;随着苦味酸浓度的增加,振荡频率增大,但超过1.5mmol.L-1前期没有振荡;苦味酸和其他协同物还对振荡曲线的规律性和重现性具有明显的影响。首次测定了电流-时间振荡曲线,发现其与电势-时间曲线具有类似的趋势,表明在液膜振荡研究中也可以通过监测电流的变化来监测振荡体系。采用自制的直型玻璃管装置,操作方便,重现性好,测定振幅可达50～200mV。

The oscillation of the liquid membrane formed by water （aqueous mixtures of cetyl trimethyl ammonium bromide （CTAB） and n-butanol） /oil （nitrobenzene-picric acid） /water （aqueous solution of glucose） was investigated. A hollow glass tube device was designed for this study. The effects of the concentrations of CTAB, picric acid or other cooperative additives on the oscillation were examined. It was found that the oscillation frequency decreased with the increase of CTAB concentration. The oscillation could not be observed when CTAB concentration was below 3 mmol · L^-1. The oscillations frequency became higher with the increase of the concentration of picric acid, and front oscillation disappeared when the concentration exceeded 1.5 mmol · L^-1. The cooperative additives also affected the regularity and repeatability of oscillation. Specially, both the curves of current-time （l-t） and potential-time （F-t） were measured firstly. It was found the l-t curve and E-t curve showed similar variance, indicating that the oscillation could also be examined by monitoring current. By using our hollow glass tube device, we could obtain the oscillations at 50-200 mV range conveniently, and get the results more repeatedly. The results were explained in terms of Marangoni effect and chemism.