Several self-assembly structures of anatase TiO2nanorods were obtained by a two-step assembly process, and these structures formed different lyotropic liquid crystal in solution. Primary self-assembly occurred in synthesis process and formed two structures, in the morphology of ribbon and honeycomb, respectively. Secondary-assembly took place when the products were placed at lower temperature, where unique structures were obtained as the relative amount of ribbon and honeycomb changed with the increase of TiO2concentration. These structures showed nematic, spherulites, and lamellar phases. The mechanism of the two-step self-assembly was clarified. The driving force of primary assembly is deduced to be anisotropic attractive force, for NRs can assemble at any concentrations, while gravity is the driving force of the secondary assembly. It is worth mentioning that this paper is the first report about spherulites composing of anatase TiO2nanorods. The spherulites obtained were negative or of tangential type, and its structure, growth process, and temperature influences were also investigated. The spherulites may have promising application in temperature microsensor.
Two-Step Self-Assembly and Lyotropic Liquid Crystal Behavior of TiO2Nanorods
