School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Soft Matter. 2016 Dec 6;12(48):9633-9640. doi: 10.1039/c6sm01615d.
Enclosed three-dimensional structures with hollow interiors have been attractive targets for the self-assembly of building blocks across different length scales. Colloidal self-assembly, in particular, has enormous potential as a bottom-up means of structure fabrication exploiting a priori designed building blocks because of the scope for tuning interparticle interactions. Here we use computer simulation study to demonstrate the self-assembly of designer charge-stabilised colloidal magnetic particles into a series of supracolloidal polyhedra, each displaying a remarkable two-level structural hierarchy. The parameter space for design supports thermodynamically stable polyhedra of very different morphologies, namely tubular and hollow spheroidal structures, involving the formation of subunits of four-fold and three-fold rotational symmetry, respectively. The spheroidal polyhedra are chiral, despite having a high degree of rotational symmetry. The dominant pathways for self-assembly into these polyhedra reveal two distinct mechanisms - a growth mechanism via sequential attachment of the subunits for a tubular structure and a staged or hierarchical pathway for a spheroidal polyhedron. These supracolloidal architectures open up in response to an external magnetic field. Our results suggest design rules for synthetic reconfigurable containers at the microscale exploiting a hierarchical self-assembly scheme.
具有中空内部的封闭三维结构一直是不同长度尺度的构建块自组装的有吸引力的目标。胶体自组装，特别是作为一种自下而上的结构制造手段，具有巨大的潜力，因为可以调整颗粒间的相互作用，利用预先设计的构建块。在这里，我们使用计算机模拟研究来证明设计的带电稳定胶体磁性颗粒自组装成一系列超胶体多面体，每个多面体都显示出显著的两级结构层次。设计的参数空间支持热力学稳定的多面体具有非常不同的形态，即管状和中空的球形结构，分别涉及到四分之一和三分之一旋转对称的亚单位的形成。尽管具有高度的旋转对称性，但这些球形多面体是手性的。自组装成这些多面体的主要途径揭示了两种不同的机制——一种是管状结构的亚单位顺序附着的生长机制，另一种是球形多面体的阶段性或分层途径。这些超胶体结构对外磁场做出响应而打开。我们的结果为利用分层自组装方案在微尺度上设计合成可重构容器提供了设计规则。
