Micellar Dynamics and Organization. A Multifield 13C NMR Spin-Lattice Relaxation and /1H/13C Nuclear Overhauser Effect Study

Article abstract of DOI:10.1021/j150652a043

An extensive 13C spin-relaxation study is presented for four micellar systems.These are dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, potassium palmitate, and sodium p-octylbenzenesulfonate.The spin relaxation data are analyzed with a relaxation model that takes into account the complexity of molecular motions in surfactant systems.The results show that the internal motions in the micelles are quite fast, occurring on a time scale of 10^-11 s, which is similar to that found for liquid hydrocarbons of comparable chain lengths.The motional restrictions imposed by the aggregate-water interface resemble those found in other types of surfactant aggregates.A correlation time associated with the motions of the whole aggregate is extracted.The value of this correlation time implies that, apart from the rotational tumbling and monomer diffusion, the micelles undergo additional motions.