Microphase separation in oil-water mixtures containing hydrophilic and hydrophobic ions

Abstract

We develop a lattice-based Monte Carlo simulation method for charged mixtures capable of treating dielectric heterogeneities. Using this method, we study oil-water mixtures containing an antagonistic salt, with hydrophilic cations and hydrophobic anions. Our simulations reveal several phases with a spatially modulated solvent composition, in which the ions partition between water-rich and water-poor regions according to their affinity. In addition to the recently observed lamellar phase, we find tubular, droplet, and even gyroid phases reminiscent of those found in block copolymers and surfactant systems. Interestingly, these structures stem from ion-mediated interactions, which allows for tuning of the phase behavior via the concentrations, the ionic properties, and the temperature.

5 pages, 4 figures

References in corpus (3)

• Local theory for ions in binary liquid mixtures
• Monte Carlo algorithms for charged lattice gases
• Boundary conditions in local electrostatics algorithms

Cited by in corpus (4)

• Mesoscale phase separation of skyrmion-vortex matter in chiral magnet-superconductor heterostructures
• Theory of electrolytes including steric, attractive, and hydration interactions
• Ionically charged topological defects in nematic fluids
• The vanishing water/oil interface in the presence of antagonistic salt