Jun Taesuk, Park Hyunjun, Jeon Seungbae, Ahn Hyungju, Jang Woo-Dong, Lee Byeongdu, Ryu Du Yeol
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
Nanoscale. 2022 Nov 24;14(45):16936-16943. doi: 10.1039/d2nr05458b.
The close-packed mesocrystal structures from soft-matter assemblies have recently received attention due to their structural similarity to atomic crystals, displaying various sphere-packing Frank-Kasper (FK) and quasicrystal structures. Herein, diverse mesocrystal structures are explored in second-generation dendrons (G2-X) designed with identical wedges, in which the terminal functionalities X = CONH and CHNH represent two levels of the strong and weak hydrogen-bonding apexes, respectively. The cohesive interactions at the core apex, referred to as the core interactions, are effectively modulated by forming heterogeneous hydrogen bonds between these two functional units. For the dendron assemblies compositionally close to each pure component of G2-CONH and G2-CHNH, their own FK A15 and C14 phases dominate other phases, respectively. We show the existence of the wide-range FK σ including the dodecagonal quasicrystal (DDQC) phases from the dendron mixtures between G2-CONH and G2-CHNH, providing an experimental phase sequence of A15-σ-DDQC-C14 as the core interactions are alleviated. Intriguingly, the temperature dependence of particle sizes shows that the high plateau values of particle sizes are maintained equivalently until each threshold temperature (), followed by a prompt decrease above the . A decrease in by alleviating the core interactions and its composition dependence suggest that the more size-dispersed particles, the more susceptibility to chain exchange with increasing temperature. Our results on the formation of supramolecular dendron assemblies provide a guide to understand the core-interaction-dependent mesocrystal structures toward the fundamental principle underlying the temperature dependence of their particle sizes.
由于软物质组装体的密排介晶结构与原子晶体在结构上相似，展现出各种球堆积弗兰克 - 卡斯帕（FK）和准晶结构，近来受到了关注。在此，我们在设计有相同楔形结构的第二代树枝状分子（G2 - X）中探索了多种介晶结构，其中末端官能团X = CONH和CHNH分别代表强氢键和弱氢键顶点的两个层次。通过在这两个功能单元之间形成异质氢键，有效地调节了核心顶点处的内聚相互作用，即所谓的核心相互作用。对于组成上接近G2 - CONH和G2 - CHNH各纯组分的树枝状分子组装体，它们各自的FK A15和C14相分别主导其他相。我们展示了在G2 - CONH和G2 - CHNH之间的树枝状分子混合物中存在包括十二边形准晶（DDQC）相在内的宽范围FK σ相，随着核心相互作用的减弱，给出了A15 - σ - DDQC - C14的实验相序列。有趣的是，粒径的温度依赖性表明，在每个阈值温度（）之前，粒径的高原值都能等效地保持，而在高于该温度时则迅速下降。通过减弱核心相互作用导致的下降及其组成依赖性表明，粒径分散性越高的颗粒，随着温度升高对链交换越敏感。我们关于超分子树枝状分子组装体形成的结果为理解核心相互作用依赖的介晶结构提供了指导，有助于揭示其粒径温度依赖性背后的基本原理。
