Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Chemistry. 2012 Mar 5;18(10):2825-31. doi: 10.1002/chem.201103585. Epub 2012 Feb 10.
A homogeneous and disordered assembly of densely packed nanocrystals 2-3 nm in size was synthesized at room temperature in an aqueous solution without the assistance of any organic molecules. The assembled nanocrystals of titanium oxides, such as anatase titanium dioxide, sodium titanate, and a solid solution with rutile tin dioxide, formed macroscopic transparent objects 2-5 mm in size. In general, it is not easy to obtain homogeneous and disordered assembly of nanocrystals without assistance of any organic molecules for the inhibition of inhomogeneous and disordered aggregation. In the present work, the formation of the hydrated layer on the surface of nanocrystals facilitated the homogeneous and disordered assembly. The crystal phases and the compositions of the nanocrystals were controlled by the tuning of the synthetic conditions, such as the initial pH and metal source concentration. Based on the formation processes and mechanisms, this approach for the coupled synthesis and assembly can be applied to a variety of nanomaterials for preparation of homogeneous but disordered assembly.
在室温下，在没有任何有机分子帮助的情况下，于水溶液中合成了尺寸为 2-3nm 的均匀无序纳米晶组装体。锐钛矿二氧化钛、钛酸钠和金红石锡二氧化钛固溶体等氧化钛的组装纳米晶形成了 2-5mm 大小的宏观透明物体。通常情况下，在没有任何有机分子抑制不均匀和无序聚集的情况下，很难获得均匀无序的纳米晶组装体。在本工作中，纳米晶表面水合层的形成促进了均匀无序的组装。通过调节合成条件，如初始 pH 值和金属源浓度，可以控制纳米晶的晶体相和组成。基于形成过程和机制，这种耦合合成和组装的方法可应用于各种纳米材料，以制备均匀但无序的组装体。
