Precise Separations and Ion Transport in Self-Assembled Membranes with 1-nm Scale Pores

Considerable attention has been directed towards the development of membranes based on highly uniform structures formed by molecular self-assembly. Such systems open the possibility of overcoming the selectivity-permeability tradeoff that is intrinsic to the operation of current state-of-the art membranes in use in a wide variety of settings. Here, we examine lyotropic self-assembly of reactive amphiphiles into gyroid and direct hexagonal mesophases, the scalable fabrication of highly-ordered nanostructured polymer thin films from such mesophases, and the performance of the resulting membranes. We consider a variety of scenarios, including molecular filtration in aqueous and non-aqueous media, and ion transport. These membranes are compelling as they circumvent the limitations of pathway tortuosity and size-dispersity of transport-regulating features found in conventional membranes. As such, they enable highly selective, or precise, molecular separations and ion transport, with pore-size tunable in steps as small as 0.1 nm. We present results highlighting how these precisely-defined membranes are enabling the development of new insight regarding molecular transport under nanoscale confinement in the presence of charge, something that is poorly understood from a fundamental perspective.