Creating Quasi Two-Dimensional Cluster-Assembled Materials through Self-Assembly of a Janus Polyoxometalate-Silsesquioxane Co-Cluster
Creating Quasi Two-Dimensional Cluster-Assembled Materials through Self-Assembly of a Janus Polyoxometalate-Silsesquioxane Co-Cluster
复制标题
通过 Janus 多金属氧酸盐-倍半硅氧烷共簇的自组装创建准二维簇组装材料
DOI：
10.1021/acs.langmuir.7b01015
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
Wang Wei
中科院分区：
文献类型：
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作者：
Wu Han;Zhang Yu-Qi;Hu Min-Biao;Ren Li-Jun;Lin Yue;Wang Wei
团簇是一类重要的纳米级分子或超原子，它们在结构、化学组成、形状和功能上表现出惊人的多样性。组装两种类型的簇正在创造新兴的簇组装材料（CAM）。在本文中，我们报告了一种有效的方法来生产准二维（2D）CAM的两种类型的球状团簇，多面体低聚倍半硅氧烷（POSS），和聚氧乙烯（POM）。为了避免两个团簇之间的宏观相分离，它们通过共价键连接形成具有Janus特征和哑铃形状的POM-POSS共团簇。这种Janus特性使共簇能够在选择性溶剂中自组装成不同的纳米聚集体，就像传统的两亲分子和大分子一样。在我们的研究中，我们得到胶束，囊泡，纳米片，和纳米带通过调整正己烷的丙酮和正己烷的混合溶剂中的含量。使用高角度环形暗场扫描透射电子显微镜（HAADF-STEM）技术直接可视化纳米片和纳米带中的簇的有序堆积。我们推断，增加包装顺序的结果在囊泡到片的转变和包装方式的变化导致的片带的转变。我们的研究结果验证了通过共团簇自组装制备准二维团簇组装材料的有效性，这是制备新型CAMs的一种新方法。
Clusters are an important class of nanoscale molecules or superatoms that exhibit an amazing diversity in structure, chemical composition, shape, and functionality. Assembling two types of clusters is creating emerging cluster-assembled materials (CAMs). In this paper, we report an effective approach to produce quasi two-dimensional (2D) CAMs of two types of spherelike clusters, polyhedral oligomeric silsesquioxanes (POSS), and polyoxometalates (POM). To avoid macrophase separation between the two clusters, they are covalently linked to form a POM–POSS cocluster with Janus characteristics and a dumbbell shape. This Janus characteristics enables the cocluster to self-assemble into diverse nanoaggregates, as conventional amphiphilic molecules and macromolecules do, in selective solvents. In our study, we obtained micelles, vesicles, nanosheets, and nanoribbons by tuning then-hexane content in mixed solvents of acetone andn-hexane. Ordered packing of clusters in the nanosheets and nanoribbons were directly visualized using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) technique. We infer that the increase of packing order results in the vesicle-to-sheet transition and the change in packing mode causes the sheet-to-ribbon transitions. Our findings have verified the effectivity of creating quasi 2D cluster-assembled materials though the cocluster self-assembly as a new approach to produce novel CAMs.