Nanoparticle microstructures templated by liquid crystal phase-transition dynamics
Nanoparticle microstructures templated by liquid crystal phase-transition dynamics
复制标题
以液晶相变动力学为模板的纳米粒子微观结构
DOI：
10.1117/12.2260841
复制
发表时间：
2017
影响因子：
3.3
通讯作者：
L. Hirst
中科院分区：
文献类型：
--
作者：
Sheida T. Riahinasab;Ahmed Elbaradei;A. Keshavarz;B. Stokes;L. Hirst
液晶（LC）相变动力学可用作控制分散纳米颗粒组装的有力工具。定制的介晶配体可以增强和调整液晶相中的颗粒分散，以产生液晶纳米复合材料——一种新型材料。软纳米复合材料最近因其在光伏、光子材料和液晶激光器等各种工业应用中的潜在用途而受到关注。我们的小组开发了一种新型相变模板工艺，用于生成通过介晶配体-配体相互作用稳定的微米级、囊泡状纳米颗粒壳。介晶配体的柔性臂结构增强了配体与局部液晶导向器的排列，从而控制纳米颗粒在液晶相中的分散和稳定。在本文中，我们详细探讨了胶囊的形成过程，在令人惊讶的广泛半径范围内生成基于量子点的胶囊。我们证明初始纳米颗粒浓度和冷却速率是影响胶囊尺寸的重要参数。通过增加纳米颗粒的浓度并降低冷却速率，我们开发了直径高达 96±19 μm 的大壳，而降低浓度并增加冷却速率则产生了小至 4±1 μm 的壳。
Liquid crystal (LC) phase transition dynamics can be used as a powerful tool to control the assembly of dispersed nanoparticles. Tailored mesogenic ligands can both enhance and tune particle dispersion in the liquid crystal phase to create liquid crystal nano-composites - a novel type of material. Soft nanocomposites have recently risen to prominence for their potential usage in a variety of industrial applications such as photovoltaics, photonic materials, and the liquid crystal laser. Our group has developed a novel phase-transition-templating process for the generation of micron-scale, vesicle-like nanoparticle shells stabilized by mesogenic ligand-ligand interactions. The mesogenic ligand’s flexible arm structure enhances ligand alignment with the local LC director, providing control over the dispersion and stabilization of nanoparticles in liquid crystal phases. In this paper we explore the capsule formation process in detail, generating QD-based capsules over a surprisingly wide range of radii. We demonstrate that the initial nanoparticle concentration and cooling rate are important parameters influencing capsule size. By increasing particle concentration of nanoparticles and reducing the cooling rate we developed large shells up to 96±19 μm in diameter whereas decreasing concentration and increasing the cooling rate produces shells as small as 4±1 μm.