Collaborative Research: Exploiting Void Symmetries to Control the Self-Assembly of Nanoparticles

主要研究者：Kumar，Sanat / Panagiotopoulos，Athanassios提案编号：1403049 / 1402166机构：哥伦比亚大学/普林斯顿大学标题：合作研究：利用空隙对称性控制纳米粒子的自组装纳米粒子的组装是一种很有前途的方法，以获得有序的纳米复合材料，其独特的性能取决于组分的选择NP。如果成功的话，这种新的方法将对实验者合理设计有序胶体晶体的能力产生重大影响，这些胶体晶体可用于广泛的光学和催化应用，如光子晶体、光学开关和滤波器以及催化装置。PI已经显示出一种新的方法，通过使用可以插层在聚合物之间的聚合物来选择性地稳定一种晶体结构而不是另一种可能的晶体结构。 PI已经做出了一个有趣的发现，即使当两个晶体同构的能量，压力和填充分数，例如，HCP和FCC是相同的，晶体内的空隙分布是不同的。通过用不同长度的聚合物填充空隙，他们能够证明可以选择性地稳定HCP而不是FCC晶体。基于这些发现，他们建议利用这种关于空隙对称性和尺寸分布的新见解，从一系列竞争晶体结构中选择所需的多晶型物。在这项提案中，他们将使用分子动力学（使用基于图形处理单元（GPU）的分子动力学模拟）和蒙特-卡罗方法来研究胶体/聚合物共混物中的胶体晶体。他们将探索具有不同构象和灵活性的聚合物的球对称和片状颗粒的几种结构，以了解如何最大化不同几何形状的空隙中的聚合物熵，以及如何引入相互作用来平衡聚合物熵。

PI: Kumar, Sanat / Panagiotopoulos, Athanassios Proposal Number: 1403049 / 1402166 Institution: Columbia University / Princeton University Title: Collaborative Research: Exploiting Void Symmetries to Control the Self-Assembly of Nanoparticles The assembly of nanoparticles (NPs) into colloidal crystals is a promising way to obtain ordered nanocomposite materials with unique properties determined by the choice of the constituent NPs. If successful, this novel approach will have a significant impact on the ability of experimentalists to rationally design ordered colloidal crystals for a wide range of optical and catalytic applications, such as photonic crystals, optical switches and filters, and catalytic devices. The PIs have shown a novel way to selectively stabilize one crystal structure over another possible one by the use of polymers that can intercalate between the NPS. The PIs have made an interesting discovery that, even when the energy, pressure, and packing fraction for two crystal isomorphs, e.g., HCP and FCC, are the same, the distribution of voids within the crystals are different. By filling the voids with polymers of different length, they were able to show that one can selectively stabilize HCP over FCC crystals. Based on these findings, they propose to make use of this novel insight about void symmetries and size-distributions to select a desired polymorph from a suite of competing crystal structure. In this proposal, they will use molecular dynamics (using Graphics Processing Unit (GPU)-based molecular dynamics simulations) and Monte-Carlo methods to study the colloidal crystals in colloid/polymer blends, . They will explore several structures of spherically symmetric and patchy particles with polymers of varying conformation and flexibility in order to understand how to maximize the polymers' entropy in voids of different geometries, and how the introduction of enthalpic interactions may act in counterbalance to the polymer entropy.