UNS: Collaborative Research: Testing the paradigms of the colloidal glass: Novel concentration jump experiments and large scale computer modeling

UNS：协作研究：测试胶体玻璃的范例：新颖的浓度跳跃实验和大规模计算机建模

• 批准号: 1506072
• 负责人: Gregory McKenna
• 金额: $ 17.5万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506072&HistoricalAwards=false
• 关键词: UNS; Collaborative; Research; Testing; paradigms

CBET - 1506072 McKenna, Gregory B.CBET - 1506079 Zia, Roseanna N.Colloids are dispersions of particles in a liquid, such as water, and the particles are so small that they do not separate for very long times. The materials are widely used in commercial products such as paints and inks. They are also believed to be a good model materials for glasses. The present work is a collaborative study that combines experiment and large scale computer simulations that will provide novel scientific understanding of the behavior of colloidal glasses and comparisons will be made with knowledge from the literature concerning molecular glasses in similar conditions. Graduate and high school students will participate in the research activities at both PIs' institutions.Understanding dynamical arrest in complex matter is a great challenge in soft matter science. Most study of colloidal systems near jamming assumes parity with corresponding behavior in molecular glasses. Yet, recent studies reveal non-equilibrium responses in colloids that differ qualitatively from glassy dynamics as monitored via the Kovacs signatures, viz., the intrinsic isotherm, the asymmetry of approach, and the memory effect. The proposed study will illuminate the structural underpinnings of such differences through a novel combination of experiment and dynamic simulation. The structure and dynamics will be determined in experiments analogous to the Kovacs experiments for molecular glass-forming systems. Here stimulus-responsive particles will change diameter at constant number density to create concentration-jump conditions to mimic the temperature-jumps of the Kovacs signature experiments. Concurrent simulations will effect similar conditions in silico. Experiment and simulation will inform and validate each other and the joint interrogation of the colloid dynamics near to the jamming transition will potentially create a transformative understanding of arrested states in soft matter. In a broader sense, this is a collaboration of two very different PIs. One is an expert in the experimental physics of molecular glasses, especially aging. The other is an expert in large scale computer simulation, with emphasis on colloidal systems. The result provides unique cross-disciplinary training to graduate students in both computational and experimental physics, deepening their knowledge of the fundamentals of dynamics and aging of molecular and colloidal glasses. Further, women and under-represented minorities will play a central role as undergraduate and graduate researchers.

CBET - 1506072 McKenna，Gregory B.CBET - 1506079 Zia，Roseanna N.胶体是颗粒在液体（例如水）中的分散体，颗粒非常小，以至于它们在很长时间内都不会分离。这些材料广泛用于油漆和油墨等商业产品。 它们也被认为是良好的眼镜模型材料。 目前的工作是一项合作研究，结合了实验和大规模计算机模拟，将为胶体玻璃的行为提供新颖的科学理解，并将与类似条件下分子玻璃的文献知识进行比较。 研究生和高中生将参加两个 PI 机构的研究活动。了解复杂物质中的动力学抑制是软物质科学中的一项巨大挑战。大多数对接近干扰的胶体系统的研究都假设与分子玻璃中的相应行为相同。然而，最近的研究表明，胶体中的非平衡反应与通过科瓦奇特征（即固有等温线、方法的不对称性和记忆效应）监测的玻璃态动力学有质的不同。拟议的研究将通过实验和动态模拟的新颖结合来阐明这种差异的结构基础。结构和动力学将在类似于分子玻璃形成系统的科瓦奇实验的实验中确定。在这里，刺激响应颗粒将以恒定的数密度改变直径，以创造浓度跳跃条件，以模拟科瓦奇特征实验的温度跳跃。并行模拟将在计算机中实现类似的条件。实验和模拟将相互告知和验证，并且对干扰转变附近的胶体动力学的联合询问将有可能对软物质中的捕获状态产生变革性的理解。 从更广泛的意义上来说，这是两个截然不同的 PI 的合作。 其中一位是分子玻璃实验物理学，尤其是老化方面的专家。另一个是大规模计算机模拟方面的专家，重点是胶体系统。该成果为计算和实验物理学方面的研究生提供了独特的跨学科培训，加深了他们对分子和胶体玻璃的动力学和老化基础知识的了解。此外，女性和代表性不足的少数族裔将作为本科生和研究生研究人员发挥核心作用。