Feng Xueyan, Zhang Ruimeng, Li Yiwen, Hong You-Lee, Guo Dong, Lang Kening, Wu Kuan-Yi, Huang Mingjun, Mao Jialin, Wesdemiotis Chrys, Nishiyama Yusuke, Zhang Wei, Zhang Wei, Miyoshi Toshikazu, Li Tao, Cheng Stephen Z D
Department of Polymer Science, College of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-3909, United States.
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China.
ACS Cent Sci. 2017 Aug 23;3(8):860-867. doi: 10.1021/acscentsci.7b00188. Epub 2017 Aug 7.
To understand the hierarchical self-organization behaviors of soft materials as well as their dependence on molecular geometry, a series of AB dendron-like molecules based on polyhedral oligomeric silsesquioxane (POSS) nanoparticles were designed and synthesized. The apex of these molecules is a hydrophilic POSS cage with 14 hydroxyl groups (denoted DPOSS). At its periphery, there are different numbers ( = 1-8) of hydrophobic POSS cages with seven isobutyl groups (denoted BPOSS), connected to the apical DPOSS via flexible dendron type linker(s). By varying the BPOSS number from one to seven, a supramolecular lattice formation sequence ranging from lamella (DPOSS-BPOSS), double gyroid (space group of 3̅, DPOSS-BPOSS), hexagonal cylinder (plane group of 6, DPOSS-BPOSS), Frank-Kasper A15 (space group of 3̅, DPOSS-BPOSS, DPOSS-BPOSS, and DPOSS-BPOSS), to Frank-Kasper sigma (space group of 4, DPOSS-BPOSS) phases can be observed. The nanostructure formations in this series of AB dendron-like molecules are mainly directed by the molecular geometric shapes. Furthermore, within each spherical motif, the spherical core consists hydrophilic DPOSS cages with flexible linkages, while the hydrophobic BPOSS cages form the relative rigid shell, and contact with neighbors to provide decreased interfaces among the spherical motifs for constructing final polyhedral motifs in these Frank-Kasper lattices. This study provides the design principle of molecules with specific geometric shapes and functional groups to achieve anticipated structures and macroscopic properties.
为了理解软材料的分级自组装行为及其对分子几何形状的依赖性,设计并合成了一系列基于多面体低聚倍半硅氧烷(POSS)纳米颗粒的AB型树枝状分子。这些分子的顶端是一个带有14个羟基的亲水性POSS笼(表示为DPOSS)。在其外围,有不同数量( = 1 - 8)的带有七个异丁基的疏水性POSS笼(表示为BPOSS),通过柔性树枝状连接体连接到顶端的DPOSS上。通过将BPOSS的数量从一变化到七,可以观察到从片层(DPOSS - BPOSS)、双连续立方相(空间群为3̅,DPOSS - BPOSS)、六方柱(平面群为6,DPOSS - BPOSS)、Frank - Kasper A15(空间群为3̅,DPOSS - BPOSS、DPOSS - BPOSS和DPOSS - BPOSS)到Frank - Kasper σ(空间群为4,DPOSS - BPOSS)相的超分子晶格形成序列。这一系列AB型树枝状分子中的纳米结构形成主要由分子几何形状决定。此外,在每个球形结构单元内,球形核心由带有柔性连接体的亲水性DPOSS笼组成,而疏水性BPOSS笼形成相对刚性的外壳,并与相邻的结构单元接触,以减少球形结构单元之间的界面,从而在这些Frank - Kasper晶格中构建最终的多面体结构单元。本研究提供了具有特定几何形状和官能团的分子的设计原理,以实现预期的结构和宏观性质。