Anatomy of triply-periodic network assemblies: characterizing skeletal and inter-domain surface geometry of block copolymer gyroids
Anatomy of triply-periodic network assemblies: characterizing skeletal and inter-domain surface geometry of block copolymer gyroids
复制标题
DOI：
10.1039/c8sm00078f
复制
发表时间：
2018-05-14
期刊：
影响因子：
3.4
通讯作者：
Grason, Gregory M.
中科院分区：
文献类型：
--
作者：
Prasad, Ishan;Jinnai, Hiroshi;Grason, Gregory M.
三周期网络(TPN)，就像众所周知的陀螺体和钻石网络相一样，丰富地存在于软物质组装中，从嵌段共聚物(BCP)、溶致液晶和表面活性剂到生物中的功能结构。虽然TPN实际上是空间变化的分子组成的体积填充模式，但物理和结构模型通常将其结构简化为低维几何对象：化学结构域之间的2D界面；以及穿过相互连接的管状域的一维骨架。这些低维结构提供了与基于三周期最小或常平均曲率表面的理想化几何结构进行比较的有用基础，并为形成网络的分子组分在空间上的异质堆积提供了重要的光。在这里，我们提出了一种简单、高效、灵活的方法来从自组装网络的三维体组成数据中提取一维骨架。我们将这种方法应用于ABA三嵌段共聚物的自洽场理论预测和实验电子显微层析重建的双回旋相。因此，我们进一步展示了对一维骨架、二维域间表面和组合的分析如何提供对多个长度尺度上的TPN的物理和结构的洞察。具体地说，我们提出并比较了网络手性和磁区厚度的简单测量，并分析了它们在理想(理论)和非理想(实验)双陀螺组件中的空间和统计分布。
Triply-periodic networks (TPNs), like the well-known gyroid and diamond network phases, abound in soft matter assemblies, from block copolymers (BCPs), lyotropic liquid crystals and surfactants to functional architectures in biology. While TPNs are, in reality, volume-filling patterns of spatially-varying molecular composition, physical and structural models most often reduce their structure to lower-dimensional geometric objects: the 2D interfaces between chemical domains; and the 1D skeletons that thread through inter-connected, tubular domains. These lower-dimensional structures provide a useful basis of comparison to idealized geometries based on triply-periodic minimal, or constant-mean curvature surfaces, and shed important light on the spatially heterogeneous packing of molecular constituents that form the networks. Here, we propose a simple, efficient and flexible method to extract a 1D skeleton from 3D volume composition data of self-assembled networks. We apply this method to both self-consistent field theory predictions as well as experimental electron microtomography reconstructions of the double-gyroid phase of an ABA triblock copolymer. We further demonstrate how the analysis of 1D skeleton, 2D inter-domain surfaces, and combinations therefore, provide physical and structural insight into TPNs, across multiple length scales. Specifically, we propose and compare simple measures of network chirality as well as domain thickness, and analyze their spatial and statistical distributions in both ideal (theoretical) and non-ideal (experimental) double gyroid assemblies.