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.

PI：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（NP）可以组装成具有潜力的超晶格材料形成表现出截然不同的光学、电子、物理和化学性质的相。该提案以过去的成功为基础，将重点关注了解相、中间相和晶体之间转变的动力学。这种动力学在这些结构的实验实现中发挥着至关重要的作用，所获得的见解将允许催化自组装过程的方法，或设计引导系统进入所需阶段的方法。从长远来看，这些结果可能会对陶瓷、塑料和半导体行业产生影响，帮助拓宽开发稳定纳米复合材料、液体装甲、光子材料胶体介晶以及光伏纳米晶体阵列的方法。Advanced Monte卡罗（例如，吉布斯-迪昂与半正则系综的积分）和分子动力学模拟将用于研究有多难（或方井吸引力）形状以不同的体积分数组织。对于这样的系统，很容易在实验上被动力学捕获（无论是作为所需的还是不需要的结构），因此不仅要了解平衡状态，而且要了解动力学，这是这里的重点，这一点非常重要。在这种情况下，所形成的中间相可以提供中间态，其降低无序态和结晶态之间的高能垒。研究不仅包括纯系统（包含一种多面体粒子），还包括二元混合物中相变的热力学和动力学。要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、截角八面体和八面体）以及这些颗粒的混合物（还包括球形颗粒）。模拟将对混合物的热力学行为进行建模，并且新的顺序参数和正向通量采样方法的变体将用于模拟相变的动力学。