Abstract
Reverse micelles, which are nanoscopic pools of water in bulk organic solvent stabilized by a surrounding layer of surfactant molecules, have been widely studied because of their resemblance to biological membranes and their ability to solubilize enzymes and catalyze biochemical reactions. Most of studies have been carried out on sodium bis(2-ethylhexyl)sulfosuccinate, known as Aerosol OT. We also employed a new synthesized surfactant, dioleyl phosphoric acid (abbreviated as DOLPA), to form reverse micelles, and DOLPA reverse micelles exhibit superior potential for protein. However, very little is known about the relationship between the molecular structure and the function of reverse micelles. Therefore, the goal of this study is to gain an atomic-level picture of the structure and dynamics of reverse micelles and some insight into the possible mechanism of fulfilling its function by molecular dynamics simulations. After substantial conformational rearrangement during the simulations, the final configurations appear to have roughly spherical shapes in the aggregate. Surfactant molecules almost cover the whole core waters. The core of the DOLPA micelle changed from a spherical to an oval shape, while the core remained spherical in an AOT reverse micelle. From the coordination number among micelle components, the difference comes from the interaction between potassium ions and the hydrophilic groups of surfactant, i.e. the phosphoric acid groups of DOLPA and the sulfuric acid groups of AOT.
