Xing Pengyao, Tham Huijun Phoebe, Li Peizhou, Chen Hongzhong, Xiang Huijing, Zhao Yanli
Division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link 637371 Singapore Singapore.
School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore.
Adv Sci (Weinh). 2017 Nov 8;5(1):1700552. doi: 10.1002/advs.201700552. eCollection 2018 Jan.
Manipulating the property transfer in nanosystems is a challenging task since it requires switchable molecular packing such as separate aggregation (self-sorting) or synergistic aggregation (coassembly). Herein, a unique manipulation of self-sorting/coassembly aggregation and the observation of switchable stimulus-responsiveness transfer in a two component self-assembly system are reported. Two building blocks bearing the same cholesterol group give versatile topological structures in polar and nonpolar solvents. One building block (cholesterol conjugated cynanostilbene, CCS) consists of cholesterol conjugated with a cynanostilbene unit, and the other one (CCN) is comprised of cholesterol connected with a naphthalimide group having a flexible long alkyl chain. Their assemblies including gel, crystalline plates, and vesicles are obtained. In gel and crystalline plate phases, the self-sorting behavior dominates, while synergistic coassembly occurs in vesicle phase. Since CCS having the cyanostilbene group can respond to the light irradiation, it undergoes light-induced chiral amplification. CCN is thermally responsive, whereby its supramolecular chirality is inversed upon heating. In coassembled vesicles, it is interestingly observed that their responsiveness can be transferred by each other, i.e., the CCN segment is sensitive to the light irradiation, while CCS is thermoresponsive. This unprecedented behavior of the property transfer may shine a light to the precise fabrication of smart materials.
在纳米系统中操纵性质转移是一项具有挑战性的任务，因为这需要可切换的分子堆积，例如分离聚集（自分类）或协同聚集（共组装）。在此，报道了在双组分自组装系统中对自分类/共组装聚集的独特操纵以及对可切换刺激响应性转移的观察。两个带有相同胆固醇基团的构建块在极性和非极性溶剂中产生了多种拓扑结构。一个构建块（胆固醇共轭氰基芪，CCS）由与氰基芪单元共轭的胆固醇组成，另一个（CCN）由与具有柔性长烷基链的萘二甲酰亚胺基团相连的胆固醇组成。得到了包括凝胶、晶体片和囊泡在内的它们的组装体。在凝胶和晶体片相中，自分类行为占主导，而在囊泡相中发生协同共组装。由于具有氰基芪基团的CCS能响应光照射，它会发生光诱导的手性放大。CCN是热响应性的，因此其超分子手性在加热时会反转。在共组装的囊泡中，有趣的是观察到它们的响应性可以相互转移，即CCN片段对光照射敏感，而CCS是热响应性的。这种前所未有的性质转移行为可能为智能材料的精确制造带来启示。
