Thermoresponsive Supramolecular Assemblies from Dendronized Amphiphiles To Form Fluorescent Spheres with Tunable Chirality
Thermoresponsive Supramolecular Assemblies from Dendronized Amphiphiles To Form Fluorescent Spheres with Tunable Chirality
复制标题
DOI：
10.1021/acsnano.1c07764
复制
发表时间：
2021-12-28
期刊：
影响因子：
17.1
通讯作者：
Zhang, Afang
中科院分区：
文献类型：
--
作者：
Liu, Yanjun;Cao, Yuexin;Zhang, Afang
结构单元的自缔合和来自拥挤诱导的空间位阻的自排斥之间的平衡解释了两亲性实体的超分子组装以形成有序结构，并且溶剂化提供了一个工具箱，以方便地通过与各种结构单元的差异相互作用来调节组装。本文报道了两亲性树枝状四苯基乙烯（TPE）与三折叠树枝状低聚乙二醇（OEGs）通过二肽Ala-Gly键在水溶液中的溶剂调节超分子手性组装。这些树枝化的两亲物可以形成具有增强的超分子手性的超分子球，这是可调的，并依赖于溶剂化。这些纳米级球形聚集体具有温敏性，其浊点温度依赖于水和THF的混合溶剂。由于OEG部分从聚集体内部向其外围的水驱动移位，相变温度随着水分数而增加。此外，热诱导的脱水和崩溃的OEG部分介导的球体之间的可逆聚集和解聚，赋予可调的聚集诱导的荧光发射（AIE）和超分子手性。实验结果和分子动力学模拟都强调了通过改变溶剂质量或热脱水的溶剂化介导的两亲性树枝化组装体的可逆手性转化取决于OEG树枝化分子与TPE部分和与溶剂分子之间的相互作用之间的平衡。
Balance between self-association of structural units and self-repulsion from crowding-induced steric hindrance accounts for the supramolecular assembly of the amphiphilic entities to form ordered structures, and solvation provides a toolbox to conveniently modulate the assemblies through differential interactions to various structural units. Here we report solvation-modulated supramolecular chiral assembly in aqueous solutions of amphiphilic dendronized tetraphenyl-ethylenes (TPEs) with three-folded dendritic oligoethylene glycols (OEGs) through dipeptide Ala-Gly linkage. These dendronized amphiphiles can form supra-molecular spheres with enhanced supramolecular chirality, which is tunable and dependent on solvation. These nanosized spherical aggregates exhibit thermoresponsive behavior, and their cloud point temperatures are dependent on mixed solvent of water and THF. The phase transition temperatures increase with water fractions due to water-driven shifting of OEG moieties from interiors of the aggregates to their peripheries. Furthermore, the thermally induced dehydration and collapse of OEG moieties mediate the reversible aggregation and deaggregation between the spheres, imparting tunable aggregation-induced fluorescent emission (AIE) and supramolecular chirality. Both experimental results and molecular dynamic simulations have highlighted that reversible chirality transformations of the amphiphilic dendronized assemblies mediated by solvation through change solvent quality or thermally dehydration are dependent on the balance between interactions of OEG dendrons with TPE moieties and with the solvent molecules.