Lyotropic Dodecagonal Quasicrystals in Ternary Amphiphile/Oil/Water Microemulsions

Aqueous lyotropic liquid crystals (LLCs) arise from the water-driven self-assembly of ionic surfactants at moderate concentrations (typically, ≥ 20 wt% in H₂O). While privileged classes of amphiphiles are now known to self-assemble in water into topologically close-packed Frank-Kasper A15 and σ phases, one recent report demonstrated that the addition of a hydrocarbon oil to these aqueous LLCs also triggers the formation of previously unknown, aperiodically ordered, lyotropic dodecagonal quasicrystals (LDDQCs) of oil-swollen micelles. However, a predictive framework for reliably assessing the propensity for specific amphiphile structures to form soft LDDQCs is currently unknown, since only one such system has been disclosed to date. This talk will present studies of a new ternary surfactant/oil/water microemulsion system that forms exceptionally well-ordered LDDQCs, with attention to their thermodynamic (meta)stability and insights into new amphiphile molecular design principles that drive the formation of these complex oil-swollen micelle packings.