溶液自组装法构筑超分子杂化功能材料

A Solution-Based Self-Assembly Approach to Preparing Functional Supramolecular Hybrid Materials

以Anderson型多金属氧酸盐(POM)为构筑单元,通过共价键的方式将两个胆固醇分子连接到POM两端,制备了一种具有胆固醇-多金属氧酸盐-胆固醇结构的杂化分子,其在本体中通过自组装形成有序的六棱柱状结构。杂化分子的POM核在N,N-二甲基甲酰胺中具有良好的溶解性,而其胆固醇端基在甲苯中具有适当的溶解性。在甲苯体积分数为85.7%的条件下,杂化分子通过POM核与其胆固醇端基溶解性的差异、胆固醇端基之间较强的范德华力和POM核之间较强的相互静电作用力,可以自组装形成不同尺度的有序纤维结构,其相互缠绕最终形成典型的三维网状结构。在纤维结构中,杂化分子通过胆固醇层与POM层相互交替排列,在透射电镜表征中形成了明暗交替的层状精细结构。本研究工作在纳米材料的设计、组装和应用方面具有潜在的应用价值。

A hybrid molecule having a molecular structure of cholesterol-polyoxometalate-cholesterol, was created by covalently connecting two cholesterol molecules onto the two sides of an organically modified Anderson-type polyoxometalate （POM）. This hybrid molecule could self-assemble into highly ordered hexagonally packed cylinders in a bulk sample. The POM cluster of the hybrid molecule dissolved well in N,N- dimethylformamide （DMF） solvent and cholesterol moieties had appropriate solubility in toluene. In mixed DMF/ toluene solvents, the hybrid molecule self-assembled into fibril-shaped aggregates. These aggregates further twisted around each other to form the three-dimensional network structures. These formations were attributed to the solubility difference between the POM cluster and cholesterol moieties, van der Waals interactions among the cholesterol moieties, and electrostatic interactions among the POM clusters. Within the fibrous structure, the POM cluster and cholesterol moieties in the hybrid molecule assembled into a well-organized structure with alternatively arranged POM layer and cholesterol layer. The results described herein has potential application value toward design, assembly, and application of nanomaterials.