Extraordinary morphologies of ZnO particles grown in a lyotropic liquid crystalline phase

Zinc oxide (ZnO) particles with extraordinary morphology and structure were observed after hydrothermal growth of the precursors in lyotropic liquid crystal (LLC) phase composed of discotic sunset yellow (SSY) molecules, sodium ions, and water. When the ZnO was grown in the conventional solution composed of zinc acetate (ZA) and hexamethylenetetramine (HMT), typical rodlike particles with hexagonal cross-section were observed. On the other hand, when the ZnO was grown in the nematic phase of the SSY, the lateral growth of the ZnO became prominent, forming discotic and donut-like particles. The lateral growth of the ZnO is thought to be induced by adsorption of the SSY and sodium ions on the polar surface of the ZnO nanorods (NRs). The morphologies and structure of the ZnO particles were experimentally analyzed, and a plausible growth model was suggested.