Micellar structures overview

Although McBain suggested over 80 years ago that soap molecules form micellar structures of lamellar and spherical shape (McBain 1913), most of the subsequent work focused on spherical micelles. The earliest concrete model for spherical micelles is attributed to Hartley (1936), whose picture of a liquidlike hydrocarbon core surrounded by a hydrophilic surface layer formed by the head groups, has been essentially verified by modern techniques, and the Hartley model still dominates our thinking. We present an overview of the structure of the micelle first and then go on to examine the details a little bit more closely. 

Time resolved SAXS/SANS allow a structural observation of kinetic processes on the nanoscale (1-100 nm) on a time scale ranging from milliseconds to hours. This allows micellar kinetics to be followed in real time, giving direct structural information of the process and its evolution. Synchrotron SAXS can reach smaller time scales and exhibits better resolution compared to neutron-based methods. However, SANS offers the possibility for contrast variation via simple H/D exchange chemistry, which opens up a world of possibilities for the investigation of kinetics in soft matter systems, in particular transport and exchange processes that otherwise would be invisible in scattering experiments. As most of these techniques have become available over recent years with advancements in both instrumentation and sample environments, there is a need for an overview of the development and the possibilities that are now available in the field of soft matter in general and micellar systems in particular. 

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