The self-assembly of ZnO nanorod bundles into interesting flowerlike architectures were achieved via a simple hydrothermal route. The as-prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and high-resolution transmission electron microscope (HRTEM). The composed ZnO nanorods, as self-assembly building blocks, are single crystals nature with the c-axis growth crystallographic direction. And most of them have diameters of 500nm and lengths of 6.0μm. The results indicate that commercial ammonia (28%) plays an important role in the formation of the flowerlike architectures in the present of ethylenediamine. When pH value is about 10 adjusted by the addition of ammonia, self-assembly of ZnO nanorod bundles into flowerlike architectures are obtained. With the further increase of the content of ammonia, self-assembly of ZnO nanorods into different flowerlike architectures are synthesized. A possible growth mechanism of the flowerlike ZnO architectures is proposed.
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