Lyotropic Liquid Crystal Assembly

Polymer electrolyte membranes (PEMs) that shuttle H+ and HO- are essential components of fuel cells and solar fuel production schemes. While various limitations of known PEMs have spurred the development of new materials, reliable molecular design criteria that guide syntheses of superior ion transporting media remain obscure. To address this fundamental yet technologically important challenge, we have developed a new small molecule surfactant platform that exhibits an unusual tendency to self-assemble in water into bicontinuous liquid crystalline phases comprised of interpenetrating aqueous and hydrophobic domains, which percolate over macroscopic lengthscales with tunable nanopore diameters (~0.6-5 nm) and well-defined pore functionalities. Using these self-assembling systems, we have produced a model set of nanoporous membrane materials that we are studying for fuel cell, water desalination, and selective chemical separations applications. We are also using these materials as an experimental platform to probe fundamental mechanisms of H+ and HO- transport in water-filled nanoporous media and to elucidate the structure of water in soft, ionic nanoconfinement using neutron scattering techniques.