Collaborative Research: Measurement, Simulation, and Theory of Molecular Connectivity Effects on Nanoscale Interfacial Rheology of Glass-Forming Fluids

合作研究：玻璃形成流体纳米级界面流变学的分子连接效应的测量、模拟和理论

• 批准号: 2208260
• 负责人: Rodney Priestley
• 金额: $ 35.5万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2208260&HistoricalAwards=false
• 关键词: Collaborative; Research; Measurement; Simulation; Theory

If you zoomed into many of the modern materials that empower energy storage, enable water purification, or even make up the tires on your car, you would find that their essential structures are only hundreds of atoms across, and at the same time are chemically connected in vast spaghetti-like strands. These “polymeric nanomaterials” open the door to new technologies that can transform our life, economy, and national defense. A major reason for their promise is also their greatest challenge: mysteriously, the interfaces that pervade these polymeric nanomaterials cause them to behave dramatically differently than traditional materials. This award aims to solve a key piece of this mystery: why do these materials deform very differently in the vicinity of these microscopic interfaces? How can we design them to control this deformation behavior and thus fabricate them more economically, further improve their properties, and ultimately enable new technological advances? These questions will be answered via experiments that zoom in to the nanometer scale to observe how these materials flow and deform. At the same time, supercomputer simulations will visualize how molecules’ movements underlie this deformation. Ultimately, these results will drive the development of a theory that explains these materials’ behavior and empowers material engineers to improve their design and drive new technological advances. The effort will be integrated with a joint Princeton and University of South Florida outreach program exposing diverse high school students to experimental and computational research on interfaces.This award will establish a predictive theoretical understanding of nanoscale gradients in rheological response at interfaces in glass-forming fluids. These gradients emanate at least in part from the presence of a glass transition temperature gradient at interfaces. However, when this gradient is spanned by large molecules, particularly in the presence of surface adsorption, it is not clear how it controls alterations in rheological response. Work aims to (1) establish a theory of alterations in linear rheology in the nanoscale vicinity of free surfaces, (2) extend this theory to treat buried interfaces relevant to composites and multi-phase fluids, and (3) establish a new strategy for altering near-interface rheological response. To support new theory development, an experimental metrology to measure time-resolved nanocreep will be combined with simulations probing gradients in rheology and chain dynamics. Predictive understanding established by this work will transform the understanding, prediction, and design of flow of interfacially-rich fluids, such as nanoparticle-laden fluids, thin films, and nanostructured multiphase fluids.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.

如果你仔细观察许多能够储存能量、净化水、甚至制造汽车轮胎的现代材料，你会发现它们的基本结构只有数百个原子，同时又通过化学方式连接在一起。这些“聚合物纳米材料”为改变我们的生活、经济和国防的新技术打开了大门，其前景的一个主要原因也是它们面临的最大挑战：神秘的是，遍布这些聚合物的界面。纳米材料导致它们的行为与传统材料显着不同，该奖项旨在解决这个谜团的一个关键部分：为什么这些材料在这些微观界面附近的变形非常不同？我们如何设计它们来控制这种变形行为，从而控制这种变形行为？更经济地制造它们，进一步改善它们的性能，并最终实现新的技术进步？这些问题将通过放大到纳米尺度以观察这些材料如何流动和变形的实验来回答，同时超级计算机模拟将如何可视化。分子运动的基础最终，这些结果将推动一种理论的发展，该理论可以解释这些材料的行为，并使材料工程师能够改进他们的设计并推动新的技术进步，这项工作将与普林斯顿大学和南佛罗里达大学的联合推广计划相结合。不同的高中生对界面进行实验和计算研究。该奖项将建立对玻璃形成流体界面流变响应中纳米级梯度的预测性理论理解。这些梯度至少部分源于玻璃化转变温度的存在。梯度为然而，当这种梯度被大分子跨越时，特别是在存在表面吸附的情况下，尚不清楚它如何控制流变响应的变化。工作的目的是（1）建立纳米尺度线性流变学的变化理论。自由表面附近，（2）扩展该理论以处理与复合材料和多相流体相关的埋藏界面，以及（3）建立改变近界面流变响应的新策略以支持新理论的发展，一种实验计量学。测量时间分辨的纳米蠕变将与流变学和链动力学中的模拟探测梯度相结合。这项工作建立的预测性理解将改变对富界面流体（例如纳米颗粒流体、薄膜）流动的理解、预测和设计。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。