(620e) Mixed Micelle Structure and Composition from SANS and MD

Surfactants are mixed with various ingredients during their formulation into products and during the use of such products. The specific interactions of surfactants in aqueous solutions with compounds such as electrolytes, polar organic solvents and solutes, other surfactants, and polymers, are manifested in changes in the formation and structure of micelles. In turn, self-assembly into micelles underlies the macroscopic performance of surfactant formulations. Accordingly, information on the structure and composition of micelles at various components and conditions is very useful. To this end, we utilize complementary experiments (small-angle neutron scattering, SANS, with contrast variation) and modeling (molecular dynamics, MD) to elaborate on how the structure of micelles formed in water by anionic surfactants (sodium dodecylsulfate, SDS, perfluorooctanoate, PFOA) responds to the presence of additives (salt [10.1016/j.colsurfa.2021.127313], urea [10.1021/acs.langmuir.1c00433], ethanol [10.1039/d1cp00049g], poly(ethylene oxide) (PEO) [10.1021/jp5023168], PEO-based amphiphilic polymers [10.1016/j.jcis.2021.10.176]) across a wide range of compositions. The detailed description that emerges of the distribution of additives or polymer segments across the micelle core and corona, reveals the operating intermolecular interactions, and can be used to rationalize the macroscopic behavior and various properties of the mixtures.