Highly selective membranes are the key materials needed to perform efficient separations of the components of complex aqueous streams in applications ranging from chemical processing to water purification to environmental remediation. Several materials have been proposed as candidates for the next generation desalination and nanofiltration membranes, such as graphene, 2 graphene oxide, 3 carbon nanotubes, among others. While individual channels in these materials show excellent transport properties, fabricating and aligning them in large scale is a daunting challenge. Biomimetic lipid-like amphiphilic monomers offer a promising way to overcome the fabrication challenge as they can self assemble and be cross-linked into highly selective, nanos-tructured lyotropic liquid crystal (LLC) membranes. Such self-assembly can be exploited in experiments to synthesize membranes with nanostructured channels. These LLC polymer membranes can be customized by changing monomer components, counterions, solvent, additives, and their composition, allowing them to organize in a variety of ways with different structure and permeability to solutes. In contact with polar and/or nonpolar solvent, hydrophobic tails and hydrophilic heads of these amphiphilic monomers can self-organize into distinct regions in a wide range of packing symmetry, depending on the relative composition, temperature, and pressure. The most common phases of LLC membranes are lamellar, hexagonal, and bicontinuous cubic (Q). These LLC phases are further classified as normal (or Type I) if the curvature of the hy- drophobic/hydrophilic interface is a net positive (oil in water) and inverted (or Type II) if the curvature of the hydrophobic/hydrophilic interface is negative (water in oil). Several groups have used gemini-shaped monomers to synthesize Q phase membranes for filtration applications. Our experimental collaborators have developed a method to build and crosslink type I bicontinuous cubic (Q I ) membranes using imidazolium-based gemini monomers with bromide counterions. Their method is both simple and relatively cost-effective, and results in a highly selective membrane. Based on black optical texture under polarized light microscopy (PLM) and d-spacing at 1/ √ 6 and 1/ √ 8 in powdered Xray diffraction (PXRD) patterns, the phase of the LLC has been identified as Q I phase. These Q I structures consists of two interwoven, non-intersecting bilayers separated by a continuous hydrophilic layer/channel continuous in all three directions (see Fig 1). Such uniform and three-dimensional continuous channels give the Q structure an advantage in filtration applications since there is no need to align the channels like in other nanoporous membranes. Experiments have demonstrated several filtration applications of these membranes such as desalination of water and breathable coatings against chemical warfare agents. Crucially, these LLC membranes are highly customizable, as there are a large number of potential monomers that will have significantly different pore sizes and pore surfaces, and thus different selectivities.