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: 2208238
• 负责人: David Simmons
• 金额: $ 30万
• 依托单位: University of South Florida
• 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=2208238&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.

如果你放大许多现代材料，这些材料可以储存能量，实现水净化，甚至可以构成你汽车的轮胎，你会发现它们的基本结构只有数百个原子，同时还以化学方式连接在一起，形成巨大的意大利面条。这些“聚合物纳米材料”为能够改变我们的生活、经济和国防的新技术打开了大门。他们承诺的一个主要原因也是他们最大的挑战：奇怪的是，这些聚合物纳米材料中弥漫的界面导致它们的行为与传统材料截然不同。这个奖项旨在解开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会有很大的不同？我们如何设计它们来控制这种变形行为，从而更经济地制造它们，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的实验来回答，观察这些材料是如何流动和变形的。与此同时，超级计算机模拟将可视化分子的运动是如何导致这种变形的。最终，这些结果将推动一种解释这些材料行为的理论的发展，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，让不同的高中生接触到关于界面的实验和计算研究。该奖项将建立对玻璃形成流体界面流变性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界面处玻璃化转变温度梯度的存在。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，它如何控制流变性反应的变化尚不清楚。工作的目的是(1)建立自由表面纳米尺度附近的线性流变学的变化理论，(2)将该理论扩展到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性响应的新策略。为了支持新的理论发展，测量时间分辨纳米环的实验计量学将与流变学和链动力学中探测梯度的模拟相结合。通过这项工作建立的预测性理解将改变对富界面流体流动的理解、预测和设计，例如纳米颗粒流体、薄膜和纳米结构多相流体。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。

项目成果

Combined Mixing and Dynamical Origins of T g Alterations Near Polymer–Polymer Interfaces

聚合物-聚合物界面附近 Tg 变化的组合混合和动力学起源

• DOI: 10.1021/acs.macromol.2c01621
• 发表时间: 2023
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Ghanekarade, Asieh;Simmons, David S.
• 通讯作者: Simmons, David S.