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.Colloids是液体中颗粒的分散体，例如水，颗粒是如此之小，以至于它们不分开很长时间。这些材料被广泛用于涂料和油墨等商业产品中。 他们也被认为是玻璃杯的好型号。 目前的工作是一项合作研究，结合了实验和大规模的计算机模拟，将对胶体玻璃的行为和比较进行新的科学理解，并与文献有关在类似条件下的分子玻璃的知识中进行比较。 研究生和高中生将参加两个PIS机构的研究活动。理解复杂物质的动态停滞是软物质科学的巨大挑战。大多数对胶体系统的研究都在分子玻璃中与相应的行为相等。然而，最近的研究揭示了胶体中的非平衡反应，这些胶体与通过Kovacs特征，即内在等温线，进近的不对称性和记忆效应进行质量不同的胶体差异。拟议的研究将通过实验和动态模拟的新组合来阐明这种差异的结构基础。在类似于分子玻璃形成系统的Kovacs实验的实验中，将确定结构和动力学。在这里，刺激反应性颗粒将在恒定数密度下更改直径，以创建浓度跳跃条件，以模仿Kovacs签名实验的温度跳跃。并发模拟将在计算机中影响类似的条件。实验和仿真将相互告知和验证，并在封闭的过渡中对胶体动力学的联合询问将有可能在软物质中对被捕状态产生变革性的理解。 从广义上讲，这是两个截然不同的PI的合作。 一个是分子眼镜实验物理学的专家，尤其是衰老。另一个是大规模计算机模拟的专家，重点是胶体系统。该结果为计算和实验物理学的研究生提供了独特的跨学科培训，从而加深了他们对分子和胶体眼镜的动力学和衰老基础知识的了解。此外，妇女和代表性不足的少数民族将在本科和研究生研究人员中发挥核心作用。