Obtaining stable bicontinuous cubic structures in lyotropic liquid crystals

Amphiphilic polymers can self-assemble into lyotropic liquid crystals of various stable phases such as micellar, hexagonal, lamellar, sponge, and bicontinuous cubic. Imidazolium-based amphiphilic monomers in polar solvents can self-assemble into bicontinuous cubic structures under the right composition and temperature. These lyotropic liquid crystal membranes, with their uniform and 3D continuous channels, are excellent candidates for several filtration applications. Molecular-level understanding is required to guide the design of these membranes with desired physical and chemical properties. To that end, we use molecular dynamics simulations to study the structure and transport through these membranes. We have developed procedures to construct all-atom and coarse-grain models of bicontinuous cubic structures that involve parameterization and assembly of the components. We then use these models to study the phase behaviors and their sensitivity to factors such as head group chemistry, monomer length, solvent dielectric properties, and so on. Moreover, we investigate the molecular transport through these membranes, including ways to optimize selectivity and permeability.