Nanomanufacturing by Heterogeneous Aggregation and Magnetic Alignment of Multi-Functional Nanoparticles

多功能纳米粒子是非常感兴趣的，因为它们能够同时响应多种刺激，并表现出组件之间的连接。该奖项支持对异质聚集或异质聚集的基础理论和实验研究，作为核/卫星纳米颗粒的纳米制造方法，该方法由不同组成的许多较小卫星纳米颗粒的外壳覆盖的核纳米棒组成。异质聚集是一种简单的方法，基于混合具有不同性质的溶剂来驱动预合成纳米颗粒的组装。该方法易于扩展到大容量。使用外部施加的磁场来对齐涂覆有磁性卫星纳米颗粒的纳米棒核在高级颜料、复合材料的机械强化和生物医学成像中具有潜在的应用。这些应用的进展影响着国家的繁荣和安全。这项研究通过开发用于进行，建模和表征异质聚集过程和磁性对齐的方法和策略，实现了纳米制造的新能力，这些方法和策略可以应用于跨越各种材料成分和长度尺度的其他系统。计划开展教育和外联活动，教育学生和教师掌握纳米科学和纳米技术，并让妇女和代表性不足的少数民族学生参与研究和纳米制造培训。由于种子生长和自组装过程的限制，多功能纳米颗粒的纳米制造仍然具有挑战性。本研究的目的是克服这些挑战，通过创建一个理论和实验框架的heteroaggregation。控制溶剂条件以及核心和卫星纳米颗粒的组成、尺寸和浓度驱动形成均匀核心/卫星纳米颗粒的异相聚集，同时避免核心或卫星纳米颗粒的均相聚集。通过分子动力学模拟预测了核/卫星纳米粒子异质聚集的条件，全面指导了实验并解释了结果。对于选定的系统，异质聚集纳米制造的可扩展性研究在批处理和连续微流体。通过分子动力学模拟和实验验证，实现了核心/卫星纳米棒的磁性对齐的理解。预测磁性卫星纳米颗粒之间的偶极相互作用提供磁性排列的扭矩，并且重要的是建立产生足够扭矩以驱动磁性排列的条件。磁性排列赋予了异质聚集体新的性质，如磁光、偏振和微观流变学，以及纳米复合材料的弹性模量。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Multifunctional nanoparticles are of great interest because of their ability to simultaneously respond to multiple stimuli and exhibit connection between components. This award supports fundamental theoretical and experimental research on heterogeneous aggregation, or heteroaggregation, as a method for nanomanufacturing of core/satellite nanoparticles consisting of a core nanorod covered by a shell of many smaller satellite nanoparticles of a different composition. Heteroaggregation is a simple approach, based on mixing solvents with different properties to drive the assembly of pre-synthesized nanoparticles. This method is readily scalable to large volumes. Use of externally applied magnetic fields to align nanorod cores coated with magnetic satellite nanoparticles has potential applications in advanced pigments, mechanical strengthening of composite materials, and biomedical imaging. Advances in these applications impact national prosperity and security. This research enables new capabilities for nanomanufacturing by developing methods and strategies for conducting, modeling, and characterizing heteroaggregation processes and magnetic alignment that can be applied to other systems spanning a wide range of material compositions and length scales. Education and outreach activities are planned to educate students and teachers in nanoscience and nanotechnology and engage women and under-represented minority students in research and nanomanufacturing training.Nanomanufacturing of multifunctional nanoparticles remains challenging due to limitations in seeded growth and self-assembly processes. This research aims to overcome these challenges by creating a theoretical and experimental framework for heteroaggregation. Controlling the solvent conditions and the compositions, sizes, and concentrations of the core and satellite nanoparticles drives heteroaggregation in forming uniform core/satellite nanoparticles, while avoiding homoaggregation of either the core or the satellite nanoparticles. Molecular dynamics simulations are performed to predict the conditions for heteroaggregation of core/satellite nanoparticles, which comprehensively guide experiments and interpret results. For selected systems, the scalability of heteroaggregation for nanomanufacturing is investigated in both batch processes and continuous microfluidics. The understanding of magnetic alignment of core/satellite nanorods is achieved through molecular dynamics simulations and experimental verification. Dipolar interactions among magnetic satellite nanoparticles are predicted to provide torque for magnetic alignment, and it is important to establish the conditions under which sufficient torque is generated to drive magnetic alignment. Magnetic alignment imparts new properties for the heteroaggregates such as magneto-optical, polarization and microrheology, and elastic modulus for nanocomposites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.