A study on the solubilization of polycyclic aromatic hydrocarbons in gemini-conventional mixed surfactant systems by 1H NMR spectroscopy

This study is an approach to especially investigate (i) the micellization behaviour of a cationic gemini surfactant 16-E2-16 (ethane-1,2-diylbis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride) and its equimolar binary mixtures with conventional cationic (CTAC), anionic (SDS), non-ionic (Brij 58) surfactants, and (ii) the solubilization capacity of the pure/mixed surfactant systems towards polycyclic aromatic hydrocarbons (PAHs) by H-1 NMR spectroscopy. Proton chemical shifts (delta, ppm) of the binary or ternary surfactant/solute systems have been compared with the pure surfactant solutions. The results (delta values) indicate favoured micellization for all the surfactant solutions and the extent of solubilization depends on the nature of surfactants as well as solutes. Location of the PAHs in different parts, such as palisade layer, inner palisade layer and core of micelles alter the delta values. More pronounced changes in delta value of various protons of CTAC and Brij 58 indicate higher solubilization of pyrene. Among all the three surfactant combinations, 16-E2-16 + SDS is the most compact system as compared to the 16-E2-16 + CTAC and 16-E2-16 + Brij 58 systems.