Mesomorphic Ceramics via Self-Assembly and Sintering of Metal Oxide Nanorods

Mesomorphic ceramics are defined as solid-state systems with intermediate order between isotropic and crystalline. A new class of mesorphic ceramics has been synthesized via lyotropic self-assembly of titanium dioxide, TiO₂, nanorods followed by sintering. A lyotropic dispersion of ligand-capped anatase nanorods forms a polydomain nematic phase and, when thermally treated, nanorods fuse together into low aspect ratio grains that preserve crystallographic orientation within textured domains. Lyotropic suspensions can be sheared and subsequently sintered to form mesomorphic ceramic monodomain with uniaxial orientation across millimeter dimensions. The resutling monodomains exhibit high optical transparency and a nearly constant birefringence. Distinct from liquid-crystal templating, this new approach yields superstructures of nanoparticles with relative ease and at lower costs. The present study opens a pathway toward robust, ceramic-based solid films for diverse applications.