Molecular Dynamics Studies of Rhamnolipid Surfactants

Glycolipid surfactants are a unique class of amphiphilic molecules composed of a polar sugar group (head) and a nonpolar alkyl group (tail). Research in glycolipid surfactants has increased in recent years thanks to interest in greener surfactants and advances in their production. Of particular interest to our research group are the rhamnolipid (RL) surfactants produced naturally by the bacteria, Pseudomonos aeruginosa. The unorthodox structure of RL surfactant offers a rich opportunity to study the aggregation behavior in both water and at the interface. Utilizing all-atom classical molecular dynamics simulation, we have shown that RL surfactatns form stable micellar aggregates in water. Our simulation results in tandem with experimental observations were vital to explain unknown physical phenomenon at the air-water interface. The potential use of RL surfactants in enhanced oil recovery (EOR) motivated us to investigate the ability of RL to trap oil molecules. This presentation will focus on the interesting results that were obtained from the simulation of RL molecules and decane as a representative hydrocarbon. Free energy perturbation calculations have provided interesting insight into the aggregation of RL in the presence of oil.