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

项目负责人：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（NPs）组装成胶体晶体是一种很有前途的方法，可以获得有序的纳米复合材料，这些材料具有由组成NPs的选择决定的独特性能。如果成功，这种新方法将对实验学家合理设计有序胶体晶体的能力产生重大影响，这些胶体晶体广泛用于光学和催化应用，如光子晶体、光学开关和滤波器以及催化装置。pi展示了一种新方法，通过使用插在NPS之间的聚合物，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有一个有趣的发现，即使两种晶体同构，如HCP和FCC，当能量、压力和填充分数相同时，晶体内的空洞分布是不同的。通过用不同长度的聚合物填充空隙，他们能够证明人们可以选择性地稳定FCC晶体上的HCP。基于这些发现，他们建议利用这种关于空洞对称性和尺寸分布的新见解，从一套竞争性晶体结构中选择所需的多晶型。在本提案中，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。他们将探索几种具有不同构象和灵活性的聚合物的球对称和片状粒子结构，以了解如何在不同几何形状的空隙中最大化聚合物的熵，以及如何引入焓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.