摘要
运用核磁共振(NMR)方法分别测定了表面活性剂辛基苯聚氧乙烯醚(TX-100)和十六烷基三甲溴化铵(CTAB)在不同温度下的临界胶束浓度.阐述了应用1D NMR线型分析方法对表面活性剂快交换体系平均停留时间的定量测量.实验测量了TX-100和CTAB胶束溶液中表面活性剂分子在不同温度下的平均停留时间.结果显示,平均停留时间随温度的增加逐渐减小,说明TX-100和CTAB分子进出胶束的速率随温度的增加逐渐加快.利用阿伦尼乌斯公式拟合,获得了TX-100和CTAB的表观交换活化能,TX-100的表观交换活化能为17.6 k J/mol,CTAB的表观交换活化能为75.3 k J/mol.对TX-100和CTAB平均停留时间和表观交换活化能进行分析,得出平均停留时间和表观交换活化能与分子结构的关系:表观交换活化能反映的是疏水相互作用和静电斥力的大小;而平均停留时间不仅受活化能的影响,还与分子结构有关.
The critical micelle concentration （CMC） of Triton X-100 （TX-100） andcetyltrimethylammonium bromide （CTAB） was measured by nuclear magnetic resonance（NMR） technologies at different temperature. The average residence time of TX-100 andCTAB were determined by one-dimensional line shape analysis. The average residencetime of both compounds decreased with increasing temperature, suggesting that the rate ofTX-100 and CTAB molecules entering/leaving the micelles increased with temperature.The apparent activation energy of the exchange process was calculated with the Arrheniusequation, and found to be 17.6 kJ/mol for TX-100 and 75.3 kJ/mol for CTAB. The apparentactivation energy likely reflected the strength of hydrophobic interaction; while the averageresidence time depended not only on the hydrophobic interaction but also on the molecularstructure.
出处
《波谱学杂志》
CAS
CSCD
北大核心
2016年第3期422-431,共10页
Chinese Journal of Magnetic Resonance
基金
国家自然科学基金资助项目(21375145)
