Micellization of sodium dodecyl sulfate in the vicinity of Krafft point: an NMR and dielectric spectroscopy study

The structural state of ionic surfactant sodium dodecyl sulfate (SDS) on passing through the Krafft point (classical characteristic parameter determining the relationship between surfactant solubility and micelle formation) was studied by two independent physical methods, NMR and dielectric spectroscopies. It was established that the micellar structure of concentrated SDS solution is preserved on cooling down to 10 °C, which is much lower than the reported Krafft point of SDS lying near 18 °C.