NMR spectra of aqueous solutions of cetyltrimethylammonium bromide (CTAB)/triton X-100 (TX-100), sodium dodecyl sulfate (SDS)/TX-100 and CTAB/TX-100/SDS surfactant mixtures were acquired. The proton chemical shifts of each component and their dependence on concentration were determined and used to derive the critical micelle concentrations (CMCs) of CTAB, TX-100 and SDS in each mixture. It was found that, in several cases, the role played by the steric effect in the synergism of surfactant mixtures were not less than that of the electrostatic interaction. The larger the cross sectional area of the polar head was, the greater the synergy would be. It is concluded that the steric effect is a major player in the synergistic effect of surfactant mixtures, especially when the electrostatic interaction is weak.
CHEN Xiao-ying
,
YU Gang-jin
,
MAO Shi-zhen
,
LIU Mai-li
,
DU You-ru
. An NMR Study on How Steric Effects Affect Synergistic Effects in Surfactant Mixtures[J]. Chinese Journal of Magnetic Resonance, 2018
, 35(1)
: 75
-80
.
DOI: 10.11938/cjmr20172577
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