Equilibrium structured liquids: Self-assembled fluid structures stabilized by nanoparticles

The gross liquid-liquid interfacial morphology of structured liquids can be altered in response to a bulk external stimulus. We previously created structured liquid droplets by jamming nanoparticles at their liquid-liquid interfaces, but these nonequilibrium systems were unstable to emulsification. To achieve better morphological stability, i.e., to avoid emulsification, we now have fabricated structured liquids with magnetic nanoparticles, finding unexpected and stable morphologies that quickly reassembled when broken apart. The stable morphologies were not always those of minimal interfacial areas. This setup provides a novel platform for studying the packing and dynamics of nanoparticles at interfaces, as well as for building thermodynamically stable liquid structures.