EAGER: Developing an Imaging Tool to Investigate the Dynamics of Nanoparticles in 2D

溶液、分散体和凝胶在生命科学和物理科学中发挥着重要作用。这些系统在从农业和化妆品等传统领域到新材料和纳米马达等尖端领域都很重要。该项目将开发一种新的成像技术，使我们能够长时间以高分辨率可视化纳米级颗粒的运动。这些研究将为纳米材料在不同材料领域的成像提供大量的机会。这些包括超薄膜中聚合物的结晶、聚合物纳米颗粒复合材料、纳米颗粒在凝胶中的扩散、纳米颗粒和聚合物分离的原位监测、用于电池应用的电化学电池的操作度监测、二维相分离行为、玻璃状和堵塞的纳米颗粒组装、非平衡系统的动力学以及由化学反应提供推进力的纳米马达的监测。这些研究将为解决材料中一些长期存在的问题开辟道路，并为控制材料的非平衡包装提供见解，包括玻璃材料的动力学和老化，玻璃材料的结构/性质关系，以及最终导致罕见事件的参数，如粒子的解扰，它可以影响材料科学，但也可以影响地球科学领域，其中这种解扰现象，就像构造板块的分离，导致了地震。技术摘要：本项目将开发一种可视化方案，同时设计分析程序和革命性的SEM样品池，以探索纳米颗粒（NPs）面密度增加时纳米球（NSs）和纳米棒（NRs）的二维组装动力学，使纳米颗粒从低密度液态变为堵塞或玻璃态；在此过程中，将以前所未有的空间分辨率监测结构和结构动力学。电子显微镜成像为纳米结构提供了最有价值的直接信息。然而，典型溶剂化颗粒的研究受到溶剂蒸气压高的限制，这限制了研究的空间分辨率和时间持续时间。我们将利用离子液体（ILs）作为替代平台，通过电子显微镜监测溶剂化软材料动力学，从而消除了对液体电池的需要。拟议的研究将通过开发仪器，通用样品池和成像软件来提高我们的知识，以解决材料科学和物理学中长期突出的真正重大挑战，即玻璃和堵塞系统的性质。通过仪器和实验协议的发展，我们将深入了解堵塞和玻璃材料的动力学，量化由NP相互作用引起的实空间结构重排，并阐明玻璃材料动力学的异质性质，这是一个具有强烈理论兴趣的主题。

Non-Technical AbstractSolutions, dispersions and gels play an important role in life and the physical sciences. These systems are important in areas ranging from the traditional, such as agriculture and cosmetics, to the cutting edge, such as new materials and nanomotors. This project will develop a new imaging technology that will allow us to visualize the motion of nanometer scale particles with high resolution for long periods of time. These studies will open a large number of opportunities in the imaging of nanoscopic materials across a range of materials areas. These include the crystallization of polymers in ultrathin films, polymer nanoparticle-composites, the diffusion of nanoparticles in gels, in situ monitoring of separations of nanoparticles and polymers, in operando monitoring of electrochemical cells for battery applications, 2D phase separation behavior, glassy and jammed nanoparticle assemblies, the dynamics of nonequilibrium systems, and in the monitoring of nanomotors, where propulsion is provided by chemical reactions. These studies will open pathways to addressing some of the most longstanding problems in materials and provide insight into controlling non-equilibrium packing of materials, including the dynamics and ageing of glassy materials, to structure/property relationships of glassy materials, and, ultimately, to the parameters that lead to rare events, like the unjamming of particles which can impact materials science but, also, area as far-reaching as geoscience, where such unjamming phenomena, as in the unjamming of tectonic plates, lead to earthquakes. Technical AbstractThis project will develop a visualization protocol, along with the design of analysis routines and a revolutionary SEM sample cell to explore the dynamics of 2D assemblies of nanospheres (NSs) and nanorods (NRs) as the areal density of the nanoparticles (NPs) increases, bringing the NPs from a low density liquid state into a jammed or glassy state; along the way, structures and structure dynamics will be monitored at unprecedented spatial resolution. Imaging with electron microscopy provides the most valuable direct information on nanoscale structure. However, studies of typical solvated particles are limited by the high vapor pressure of the solvents which limits both spatial resolutions and the temporal duration of the studies. We will utilize ionic liquids (ILs) as an alternate platform to monitor solvated soft material dynamics by electron microscopy eliminating the need for a liquid cell. The proposed studies will advance our knowledge by developing instrumentation, versatile sample cell, and imaging software, to tackle a long-outstanding, truly grand challenge in materials science and physics, i.e., the nature of glassy and jammed systems. Through the development of the instrumentation and experimental protocols, we will gain insight into the dynamics of jammed and glassy materials, quantify the real-space structural rearrangements arising from NP interactions, and elucidate the heterogeneous nature of dynamics in glassy materials, a topic of intense theoretical interest.