Surface activity and thermodynamic data for pyridinium surfactants with an aminoacylmethyl group
作者:Zhuo Feng、Xiangfeng Guo、Lihua Jia、Yu Zhang
DOI:10.1007/s11164-013-1492-6
日期:2015.6
A series of cationic surfactants of the type 1-(alkylcarbamoylmethyl)pyridinium chloride (C n cmpCl, n = 12, 14, 16) was synthesized in high yield by use of a simple method. The chemical structures of C n cmpCl were confirmed by 1H NMR and 13C NMR spectroscopy and ESI–MS. The surface activity of C n cmpCl and thermodynamic data for micelle formation were investigated by measurement of surface tension and conductivity in pure water and in aqueous solutions of sodium chloride of different concentration at different temperature. The results showed a general decrease of CMC for C n cmpCl with the aminoacylmethyl group compared with traditional pyridinium surfactants. The effect of NaCl concentration on the surface activity of C n cmpCl was obvious. However, CMCs of C n cmpCl are not sensitive to temperature in pure water. Elevation of temperature does not favor micelle formation, and increasing the length of the hydrophobic chain is beneficial to micelle formation. Moreover, micelle formation is a thermodynamically favorable process, and the micellization process is entropy-driven.
采用简单的方法高产合成了一系列 1-(烷基氨基甲酰甲基)吡啶氯化物型阳离子表面活性剂(C n cmpCl,n = 12, 14, 16)。通过 1H NMR 和 13C NMR 光谱以及 ESI-MS 确认了 C n cmpCl 的化学结构。通过测量纯水和不同浓度氯化钠水溶液在不同温度下的表面张力和电导率,研究了 C n cmpCl 的表面活性和胶束形成的热力学数据。结果表明,与传统的吡啶表面活性剂相比,带有氨基酰甲基的 C n cmpCl 的 CMC 普遍降低。NaCl 浓度对 C n cmpCl 表面活性的影响非常明显。然而,在纯水中,C n cmpCl 的 CMC 对温度并不敏感。温度升高不利于胶束的形成,而增加疏水链的长度则有利于胶束的形成。此外,胶束的形成是一个热力学上有利的过程,而胶束化过程是由熵驱动的。