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

多功能纳米粒子因其能够同时响应多种刺激并显示出组分之间的联系而引起人们的极大兴趣。该奖项支持关于异质聚集或异质聚集的基础理论和实验研究，作为纳米制造核心/卫星纳米颗粒的方法，核心/卫星纳米颗粒由一个核心纳米棒覆盖，外壳由许多不同组成的较小卫星纳米颗粒组成。异相聚集是一种简单的方法，基于混合不同性质的溶剂来驱动预先合成的纳米颗粒的组装。这种方法很容易扩展到大容量。利用外加磁场来对准包裹有磁性卫星纳米颗粒的纳米棒核心，在先进颜料、复合材料的机械强化和生物医学成像方面具有潜在的应用。这些应用的进步影响到国家的繁荣和安全。这项研究通过开发方法和策略来进行、建模和表征异质聚集过程和磁排列，从而使纳米制造具有新的能力，这些方法和策略可以应用于跨越广泛材料组成和长度尺度的其他系统。计划开展教育和宣传活动，对学生和教师进行纳米科学和纳米技术方面的教育，并让妇女和代表性不足的少数族裔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。本研究旨在通过建立异质聚集的理论和实验框架来克服这些挑战。控制溶剂条件以及核心和卫星纳米粒子的组成、大小和浓度可以促进形成均匀的核心/卫星纳米粒子的异质聚集，同时避免核心或卫星纳米粒子的同质聚集。分子动力学模拟用于预测核心/卫星纳米粒子的异相聚集条件，从而全面指导实验和解释结果。对于选定的体系，在间歇过程和连续微流体中研究了用于纳米制造的异相聚集的可扩展性。通过分子动力学模拟和实验验证，实现了对核心/卫星纳米棒磁取向的理解。磁性卫星纳米粒子之间的偶极相互作用被预测为提供磁对准的扭矩，重要的是建立产生足够扭矩的条件来驱动磁对准。磁取向为异质聚集体赋予了新的性质，如磁光、偏振和微观流变学，以及纳米复合材料的弹性模数。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.