Surfactant monolayers on the oil/water interface: Elastic properties and molecular packing from molecular simulations.

Molecular simulations are an attractive tool for bridging the gap between theory and experiment. In this talk we will explore the relation between surfactant structure, molecular packing in the monolayer, and the elastic properties of the interface. We use Dissipative Particle Dynamics (DPD) simulations and simple bead-spring model surfactants that allow for systematic variations of chain length, branching, and density. We study how these variations affect the interfacial tension and bending rigidity. The molecular packing at the interface can explain a discrepancy between mean-field theories and recent experimental results. Elastic properties play a crucial role for emulsion stability: We will also discuss the relation between surfactant structure, elastic propeties, coalesence barriers and coalescence rates.