树枝状大分子(dendrimer)是一种高度支化、纳米尺度的人工合成大分子,具有独特的物理化学性能和重要的应用前景。利用具有8个可官能化顶点的多面体低聚倍半硅氧烷(POSS)作为树枝状大分子的核心,可在一定程度上简化树枝状大分子繁琐的合成与分离过程,在低代数时就可获得较大的表面官能团密度,并使树枝状分子呈现球形对称结构。POSS基树枝状大分子结合了POSS和树枝状分子结构与性能的优势,是一类极具潜力的有机一无机纳米杂化材料。本文综述了近年来POSS基树枝状大分子的最新研究成果,介绍了具有代表性的POSS基树枝状大分子的合成方法以及它们在催化剂、生物材料、液晶材料和发光材料等领域的应用研究进展,并对该新型材料的发展趋势做了展望。
Dendrimer is one type of macromolecules with well-defined, highly-branched and nano-scaled architectures, composed of three distinct domains: core, branches and terminal groups. Its potential functions and applications are explored based on the unique physical and chemical features due to special molecular architecture. Using polyhedral oligomerie silsesquioxanes (POSS) as the core of dendrimers is an effective and facile way to simplify the tedious repetitive steps of preparation and separation. Since POSS allows eight branches to radiate from a silicon-oxygen rigid cubic core, the dendrimers can be constructed in a well-controlled globular, three- dimensional framework, and large numbers of peripheral groups can be obtained at relatively low generation numbers. As a kind of novel nano-hybrid supermolecules, POSS-based dendrimers have attracted considerable interest in materials science. In this review, we briefly introduce the synthetic approaches of some typical POSS- based dendrimers categorized by the different chemical composition of branching units, and then focus on the potential functions and applications of this nano-hybrid material in the fields of catalysis, gene and drug delivery, liquid crystals, light harvesting and energy transfer. The specific and excellent properties imparted by the incorporation of POSS into dendrimers are also presented. Finally, the advances of POSS-based dendrimers are prospected.