Novel Materials for Membrane Applications

Lytotropic Liquid Crystals (LLCs) are amphiphilic molecules containing a hydrophobic organic tail section and a hydrophilic headgroup, which self-assemble in the presence of water or other hydrophilic species into highly ordered, yet fluid phase-separated assemblies with specific nanometer-scale hydrophilic domains. Depending on the shape of the constituent LLCs and the interfacial curvature energy of the system, monodispersed hydrophilic domains ranging in structure from lamellae to cylindrical channels to three-dimensionally interconnected pores with dimensions in the 1–5 nm size range can be formed. By making polymerizable analogs of LLC mesogens, it has been possible to stabilize the various LLC assemblies with retention of phase microstructure via photo-initiated radical cross-linking. These membranes have charged pores and reject ions in solution analogous to reverse osmosis and small neutral solutes based on size similar to nanofiltration membranes. These membranes have demonstrated exceptional performance to treat fracking water, reject chemical warfare agents, and operate for electrochemical applications.