(204a) Understanding the Effect of Radial Confinement on Phase Behavior of Surfactants

Surfactant adsorption in nanopores is crucial in surfactant-enhanced oil recovery, groundwater remediation, ultrafiltration and extraction of commercially valuable materials from rocks. An understanding of the effect of porous confinement on the self-assembly of surfactants is essential for designing new materials for applications mentioned above. The aggregative adsorption of pentaethylene glycol monohexyl ether in cylindrical pores of silica materials is studied using all-atom Molecular Dynamics. The effect of confinement on temperature-induced reconfiguration of self-assembled states of surfactants is explored as a function of decreasing pore diameters (increasing curvatures). We find that regardless of the curvature, the surfactants display cooperative adsorption behavior with an increased uptake with increasing temperature. The simulations show that the morphology of the surfactant assemblies is strongly dependent on the pore-diameter and undergoes dynamic reconfiguration with increasing curvature. We will discuss the role of pore-curvature on morphologies, the cooperative adsorption behavior and associated mechanism.