Zhengmin Li

Abstract:

In this work, we use molecular dynamics simulations to study micellization processes and phase behavior in supercritical solvent/surfactant/solute systems and develop a fundamental understanding of the equilibrium and dynamic properties of polymeric materials in CO2-related systems. The simulations are performed on a model mixture of freely jointed square-well chains (surfactants or block copolymers) and square-well spheres (solvents and solutes). We can find the critical micelle concentrations that represent the formations of micelles and explore the details about the micelles such as their sizes and shapes. The average aggregate sizes, the shapes and the size distributions of micelles will give us information about the phase transition and equilibration of simulated micellar systems. We have already successfully calculated thermodynamic properties of short surfactants in a model solvent. We are extending this work to longer chain surfactants and to investigate the effect of varying the temperature, density, surfactant architecture on the micellization process. We will generate phase diagrams for the surfactants studied which will allow us to identify the general trends observed in all cases as well as particular features of specific surfactants.