Dynamic Light Scattering Studies of Dodecyldimethyl-Ammonium Chloride Micelles
In this work, we use the dynamic light scattering technique of photon correlation spectroscopy to study the properties of micellar dodecyldmethyl-ammonium chloride (C12H25(CH3) 2NHC1, abbreviated DDAC). This system has been extensively studied by S. Ikeda and co-workers1 using surface tension, viscosity, static light scattering and C-13 NMR measurements. From these studies it was observed that at surfactant concentrations well above the critical micelle concentration the micelles undergo some kind of transition as the ionic strength is changed by adding increasing amounts of NaCl. From the evidence thus far obtained, a transition from spherical micelles at low salt concentrations to flexible rod-like micelles at high salt concentrations has been proposed. This theory has also been used to explain data from another well-studied micelle system, SDS,2 but much controversy exists.3
KeywordsSurfactant Concentration Hydrodynamic Radius Spherical Micelle Static Light Scattering Translational Diffusion Coefficient
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