Kinetics and Thermodynamics of the Self-Assembly of Polyhedral Nano-Colloids into Pure and Mixed Crystals

多面体纳米胶体自组装成纯晶体和混合晶体的动力学和热力学

• 批准号: 1403118
• 负责人: Fernando Escobedo
• 金额: $ 28.38万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1403118&HistoricalAwards=false
• 关键词: Kinetics; Thermodynamics; Self; Assembly; Polyhedral

PI: Escobedo, Fernando A.Proposal Number: 1403118Institution: Cornell UniversityTitle: Kinetics and Thermodynamics of the Self-Assembly of Polyhedral Nano-Colloids into Pure and Mixed CrystalsPolyhedral nanoparticles (NPs) can be assembled into super-lattice materials that has the potential to form phases exhibiting vastly different optical, electronic, physical, and chemical properties. This proposal, building on past successes, will focus on understanding the kinetics of the transitions between phases, mesophases, and crystals. Such kinetics play a crucial role in the experimental realization of these structures and the insights gained would allow ways to catalyze the self-assembly process, or design ways to steer the systems into desirable phases. In the long term, such results could have an impact on the ceramic, plastics, and semiconductor industries by helping broaden the approaches available to develop stable nanocomposites, liquid armors, colloid-based mesocrystals for photonic materials, and nanocrystal arrays for photovoltaics.Advanced Monte Carlo (e.g., Gibbs-Duhem integration with semi-grand canonical ensembles) and Molecular Dynamics simulations will be used to study how hard (or square-well attraction) shapes organize at different volume fractions. For such systems, it's easy to become kinetically trapped experimentally (either as a desired or undesired structure), so it's very important to understand, not just the equilibrium state, but the kinetics, which is the focus here. In this context, the mesophases that are formed may provide intermediate states that lower the otherwise high energy barrier between disordered and crystalline states. The investigations will include not just pure systems (containing one type of polyhedral particles), but also the thermodynamics and kinetics of phase transitions in binary mixtures. Particles to be investigated include polyhedra that can be produced in experiments (cubes, cuboctahedra, truncated octahedra, and octahedra), and mixtures of those (including also spherical particles). The simulations will model the thermodynamic behavior of the mixtures, and new order parameters and variants of the forward flux sampling method will be used to simulate the kinetics of phase transitions.

主要研究者：Escobedo，Fernando A.提案编号：1403118机构：康奈尔大学标题：多面体纳米胶体自组装成纯晶体和混合晶体的动力学和热力学多面体纳米粒子（NPs）可以组装成超晶格材料，具有形成表现出极大不同的光学，电子，物理和化学性质的相的潜力。该提案以过去的成功为基础，将侧重于理解相，中间相和晶体之间的过渡动力学。这种动力学在这些结构的实验实现中起着至关重要的作用，所获得的见解将允许催化自组装过程的方法，或设计将系统引导到理想阶段的方法。从长远来看，这样的结果可能会对陶瓷，塑料和半导体行业产生影响，有助于拓宽可用于开发稳定的纳米复合材料，液体装甲，用于光子材料的胶体基介晶以及用于光子学的纳米阵列的方法。Gibbs-Duhem集成与半巨正则系综）和分子动力学模拟将被用来研究如何硬（或方阱吸引）形状组织在不同的体积分数。对于这样的系统，很容易在实验上被动力学捕获（无论是作为期望的还是不期望的结构），因此不仅要理解平衡状态，而且要理解动力学，这是这里的重点。在这种情况下，所形成的中间相可以提供中间态，其降低了无序态和结晶态之间的高能量势垒。研究不仅包括纯系统（包含一种多面体粒子），还包括二元混合物相变的热力学和动力学。待研究的颗粒包括可以在实验中产生的多面体（立方体、立方八面体、截顶八面体和八面体）以及这些的混合物（也包括球形颗粒）。模拟将模拟混合物的热力学行为，新的顺序参数和变量的前向通量采样方法将用于模拟相变的动力学。