Chinese Journal of Magnetic Resonance ›› 2019, Vol. 36 ›› Issue (2): 219-224.doi: 10.11938/cjmr20172610

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Mixing-Induced Decreases in Critical Micelle Concentration in Aqueous Solution of Surfactants:Probing into the Mechanisms with 1H NMR Spectroscopy

CHEN Xiao-ying1,2, YU Gang-jin1,2, 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:2017-12-12 Published:2018-01-30
  • Supported by:
    the National Natural Science Foundation of China (21375145, 21221064).

Abstract: As revealed by 1H NMR experiments, the critical micelle concentration (CMC) of a surfactant in the aqueous solution decreases when a surfactant of different type is mixed in, a phenomenon that has been explained by the adsorption equilibrium theory. It has also been observed that the extents of mixing-induced reduction in CMC values differ among different surfactant types, depending on the interactions (absorption or repulsion) between the adsorbed surfactant molecules and the adsorption mono-layer. The results of 1H NMR experiments provided a clear picture for the so-called "synergistic effect", and thus might be used to guide the optimization of surfactant mixture formula to achieve desired performance.

Key words: nuclear magnetic resonance (NMR), mixed surfactants, critical micelle concentrations (CMC), adsorption equilibrium, synergistic effect

CLC Number: