Self-Assembly Route to TiO2 and TiC with a Liquid Crystalline Order

We report the liquid crystalline self-assembly of cellulose nanocrystals (CNCs) with peroxotitanate to replicate large freestanding mesoporous films of TiO2 and chiral nematic TiC structures. The compatibility of cellulose liquid crystals with water-soluble peroxotitanate enabled them to self-assemble into flexible chiral nematic TiO2/cellulose composite films. The highly compatible peroxotitanate/CNC mixture is a new liquid crystalline system to investigate the development of photonic films with tunable optical properties and structural replication by varying the ratio of constituents. Iridescent peroxotitanate/CNC composites were heated under hydrothermal conditions and calcined to generate layered mesoporous anatase TiO2 replicas that are robust, semitransparent films. Through magnesiothermic reduction, we transformed carbonized peroxotitanate/ CNC assemblies to mesoporous TiC with a chiral nematic order. Our work shows the potential of the mesoporous TiC to function as a long-life cycle rechargeable lithium-ion battery anode material and may extend this route to other peroxometallate compounds.