Peripheral groups of polyhedral oligomeric silsesquioxane (POSS) core-based dendrimers: a crucial factor for higher-level supra-architecture building
Peripheral groups of polyhedral oligomeric silsesquioxane (POSS) core-based dendrimers: a crucial factor for higher-level supra-architecture building
复制标题
基于多面体低聚倍半硅氧烷（POSS）核心的树枝状聚合物的外围基团：高层超架构构建的关键因素
作者：
Huiwen He;Hao Zheng;Meng Ma;Yanqing Shi;Zengliang Gao;Si Chen;Xu Wang
在POSS-Lys-X， X: -Boc, -Cbz， -Fmoc等一系列基于poss的树突状凝胶中，研究了树突状分子上的外周基团（pg）在纳米纤维分层组装的自发高级组织中的作用。我们证明pg不仅影响溶液中的凝胶能力，而且影响有序纠缠的纤维超分子网络的构建，例如。“丝瓜络”网络。由于PGs（特别是-Boc基团）导致较低的协同组装，因此纳米纤维在上层结构中的高阶纠缠可以很容易地实现凝胶体具有最低势能的稳定状态。含有-Boc基团的树状大分子表现出较低的摩尔焓和摩尔熵凝胶化，这有助于构建独特的三维（3D）“丝瓜状”上层结构。相反，树状大分子（-Cbz作为PG）的高协同组装促进凝胶进入更高焓的凝胶化过程，并构建正常的纤维网络。因此，通过热力学方法，基于poss的树状大分子的PGs是控制分层自组装的关键因素。本研究为阐明树状大分子的PGs、超结构和凝胶性能之间的关系提供了新的视角，这将进一步指导功能超分子材料的可控自组装设计。
The role of peripheral groups (PGs) on dendrimers in the spontaneous higher-level organization of hierarchically assembled nanofibers was investigated in a series of POSS-based dendritic gelators (POSS-Lys-X, X: -Boc, -Cbz, -Fmoc,etc.). We demonstrate that the PGs not only affect the gelation ability in solutions, but also the construction of orderly entangled fibrous supramolecular networks,e.g., "loofah-like" networks. Attributed to the PGs (especially the -Boc group) causing a lower cooperative assembly, the steady state with the lowest potential energy of gelators can be easily achieved by the higher ordering of nanofiber entanglement into superstructures. The -Boc group-containing dendrimers show low molar enthalpy and molar entropy of gelation, which help the construction of unique three-dimensional (3D) "loofah-like" superstructures. In contrast, the high cooperative assembly of the dendrimer (-Cbz as the PG) promotes the gelator into a higher enthalpy gelation process, with a constructed normal fibrous network. Hence, the PGs of POSS-based dendrimers act as the crucial factor in controlling the hierarchical self-assemblyviaa thermodynamics approach. This research presents new perspectives to explicate the relationships between PGs of dendrimers, supra-architectures and gel performances, which further guide the design of functional supramolecular materialsviacontrollable self-assembly.