Chinese Journal of Magnetic Resonance ›› 2016, Vol. 33 ›› Issue (3): 422-431.doi: 10.11938/cjmr20160307

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Exchange Kinetics of Surfactants TX-100 and CTAB Investigated by 1H NMR Spectroscopy

YU Gang-jin1,2, LIU Jun1, MAO Shi-zhen1, LIU Mai-li1, DU You-ru1   

  1. 1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences), Wuhan 430071, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2015-09-09 Revised:2016-07-11 Online:2016-09-05 Published:2016-09-05

Abstract:

The critical micelle concentration (CMC) of Triton X-100 (TX-100) and cetyltrimethylammonium bromide (CTAB) was measured by nuclear magnetic resonance (NMR) technologies at different temperature. The average residence time of TX-100 and CTAB were determined by one-dimensional line shape analysis. The average residence time of both compounds decreased with increasing temperature, suggesting that the rate of TX-100 and CTAB molecules entering/leaving the micelles increased with temperature. The apparent activation energy of the exchange process was calculated with the Arrhenius equation, and found to be 17.6 kJ/mol for TX-100 and 75.3 kJ/mol for CTAB. The apparent activation energy likely reflected the strength of hydrophobic interaction; while the average residence time depended not only on the hydrophobic interaction but also on the molecular structure.

Key words: liquid NMR, line shape analysis, surfactant, average residence time, apparent activation energy

CLC Number: