The Interaction Between The Malachite Green Surfactant Aggregates

The location of Malachite green in CTAB micelles and the effects of Malachite green on the first cmc, the aggregation numbers N, the diffusion coefficients D, and the diffusion activation energies of CTAB micelles have been studied. The results show that the electron-rich N in the MG can supply electron to the CTAB cation, which leads to the location of MG in the outside of micellar palisade. The interaction between MG and CTAB micelles increases the cmc of CTAB micelles, the aggregation numbers N of CTAB micelles, and the diffusion activation energy of CTAB micelles and decreases the diffusion coefficient D of CTAB micelles.The interaction between Malachite green and CTAB/n-CnH2n+1OH/H2O mixed micelles has been studied by UV-vis and fluorescent spectroscopy. The results show that MG can fade in the CTAB micelles, but in the CTAB-alcohol mixed micelles, with the increase of the concentration and the chain length of alcohol, the fading effect of MG decreases. Further studies indicate that MG can locate in the outside of the palisade of CTAB-alcohol mixed micelles spontaneously. The distribution coefficient KD of MG between the CTAB-alcohol mixed micelles and the aqueous phase increases with the increase of the concentration and the chain length of alcohol.The interphase electrochemistry properties of SDS/n-C5H11OH/H2O system and the influence of Malachite green on these properties were studied by using voltammetry without any probe and capacitance measurements. The results show that at the weight ratio of n-C5H11OH/H2O=50/50, with the increase of the total concentration of SDS in the system, the content of SDS in the upper phase increases slowly, and the second cathodic peak current of SDS in the upper phase increases slowly too, the structure of the upper phase is always W/O microemulsion. When the total concentration of SDS is more than 3%, the content of SDS in the lower phase shows remarkable increase,while the second cathodic peak current of SDS in the lower phase decreases rapidly, which indicates that the lower phase turns from O/W to BI microemulsion. This structure transformation in the lower phase makes the increase of the interphase potential AE apparently slow down after the total SDS content is more than 3%. At the constant concentration of SDS, with the increase of the Malachite green, the second cathodic peak potential and peak current of SDS in both the upper and lower phases, the interphase capacitant and interphase charge transfer current of the system all increase, while the interphase potential and interphase resistance decrease. These changes are closely connected with the static interaction between Malachite green and SDS.