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

非技术摘要溶液、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电机等尖端领域都很重要。该项目将开发一种新的成像技术，使我们能够以高分辨率长时间可视化纳米级粒子的运动。这些研究将为纳米材料在一系列材料领域的成像提供大量机会。这些领域包括聚合物在超薄膜中的结晶、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现场监测、电池应用的电化学电池的操作监测、2D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的纳米电机的监测。这些研究将为解决材料中一些最长期存在的问题开辟道路，并为控制材料的非平衡堆积提供洞察力，包括玻璃材料的动力学和老化，玻璃材料的结构/性能关系，以及最终导致罕见事件的参数，如粒子的不阻塞，它不仅可以影响材料科学，而且还可以影响地球科学等影响深远的领域，在这些领域，这种不阻塞现象，如构造板块的不阻塞，会导致地震。技术摘要本项目将开发可视化协议，以及分析程序和革命性的扫描电子显微镜样本室，以探索随着纳米颗粒(NP)面密度的增加而由纳米球(NSS)和纳米棒(NRs)组成的2D组装的动力学，使纳米颗粒从低密度液体状态进入堵塞或玻璃态；在此过程中，结构和结构动力学将以前所未有的空间分辨率进行监测。电子显微镜成像提供了有关纳米结构的最有价值的直接信息。然而，对典型溶剂化粒子的研究受到溶剂高蒸气压的限制，这既限制了空间分辨率，也限制了研究的时间持续时间。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的动力学，从而消除了对液室的需求。拟议的研究将通过开发仪器、通用样品池和成像软件来促进我们的知识，以解决材料科学和物理学中长期悬而未决的、真正重大的挑战，即玻璃和堵塞系统的性质。通过仪器和实验方案的发展，我们将深入了解堵塞和玻璃材料的动力学，量化由NP相互作用引起的真实空间结构重排，并阐明玻璃材料动力学的异质性，这是一个非常有理论意义的话题。

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.