微观尺度高分子协同组装ZnO纳米片

Polymer-Assisted Micro-Scale Assembly of ZnO Nanosheets

以醇水混合体系作为反应介质，六水合硝酸锌和尿素为原料，聚乙烯吡咯烷酮（PVP）作为模板剂，经水热过程合成了由纳米片组装的花状微球碱式碳酸锌前驱体。经热处理得到相应的氧化锌（ZnO）产物。采用X射线衍射（XRD）和环境扫描电镜（SEM）对样品进行了表征，结果表明产物为六方纤维矿结构的ZnO，单分散花状微球直径约为2μm，尺寸均一，组装成微球的纳米片构筑单元厚度为20nm。红外分析表明PVP与Zn^2＋之间的化学配位作用发生在侧环的内酰基C=O键上的O位与Zn^2＋之间，研究表明PVP用量影响组装过程，在相同实验条件下，用聚乙二醇（PEG）代替PVP的模板作用，得到了粒径较大的纳米片组装的微球（Ф-15μm），在此基础上探讨了高分子结构对晶体生长和组装机制的影响。

The nanosheets-based flower-like micropheres of layer Zn.s（CO3）2（OH）6 precursor were prepared via hydrothermal process using polyvinyl pyrrolidone（PVP） as the template in a mixed solution of ethanol and water, and the corresponding ZnO nanosheets assembled microsphere was obtained by the following calcination treatment. The samples were characterized using X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The XRD pattern of the product is indexed very well to hexagonal wurtzite structure of ZnO. The monodispersed flower-like ZnO nanosheets microspheres have a nearly homogeneous size of -2μm, and the thickness of the nanosheets assembled building blocks is -20nm. The study shows that the concentration of PVP affects the assembly process. The size of ZnO micropheres increases to -15μm when polyethylene glycol（PEG） is used instead of PVP under the same experimental condition. The impact of polymer structure on the crystal growth and the assembly process is also discussed.