Computational study of ionic surfactants self-aggregation in deep eutectic solvents.

Abstract

Deep Eutectic Solvents (DES) are, among ionic liquids and supercritical fluids, called neoteric solvents due to their physical and chemical properties that distinguish them from traditional solvents and make new applications possible, as in the nano-material synthesis. For those applications, it is important to characterize both self-aggregation and colloid stabilization in DES driving forces. Usually used models to describe the electrical double layer are inappropriate in DES, and yet there is no hydrophobic effect characterization in this type of solvents - in which the hydrogen bond network is more complex than in watery solutions, due to the capacity of both ions and molecular components operate as hydrogen bonds donors and receptors. Ionic surfactants self-aggregation involves the hydrophobic effect, that tends to segregate the apolar tail, and the formation of an electric double layer, that limits the micelle growth and keeps them disperse, being a sound model system to evaluate the nature of those forces in computational simulations. Thus, this work proposes to perform classical molecular dynamics simulations of sodium dodecyl sulfate in the DES relina and in a mixture of both solvents. It is known that the ionic micelles in DES have an increased stability, and with the intended simulations, the reasons for this will be investigated, characterizing the solvent electric double layer and hydrogen bond network. With this project, we intended that the student learns in addition to the molecular dynamics techniques and analysis tools, an ample vision of molecular structure and complex systems' physical properties correlations. Therefore, it is hoped that the student acquires experience in driving a research project in a critical way.