RUI: Dynamic Light Scattering Test of Bond Model Predictions for the Dynamics of Network-forming Liquids near the Glass Transition

RUI：键模型预测玻璃化转变附近网络形成液体动力学的动态光散射测试

• 批准号: 0906640
• 负责人: David Sidebottom
• 金额: $ 37万
• 依托单位: Creighton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906640&HistoricalAwards=false
• 关键词: RUI; Dynamic; Light; Scattering; Test

Technical AbstractThe amorphous solid phase is, in principle, endemic to all liquids despite a propensity for some liquids to crystallize when cooled. However, the manner in which a liquid thickens in advance of solidification is vastly different among different materials. Past research has demonstrated a clear link between the dynamics of a supercooled, glass-forming liquid and its chemical structure and thermodynamic properties referred to as "fragility". In this project, dynamic light scattering, Raman spectroscopy and differential scanning calorimetry are being applied to probe how liquid dynamics are directly affected by simple structural changes created in network-forming systems. The results will form a precise test of a proposed thermodynamic model (Bond Model) presently available. Work will be carried out both by graduate (MS) and undergraduate students providing hands-on research experience to augment their science education. Non-technical AbstractTechnology thrives on exploiting the novel properties of materials. Among these, glassy materials possess unique mechanical, optical and electrical properties of importance for many state-of-the-art devices. However, for their potential to be realized, glassy materials must be solidified from the liquid state without crystallization occurring. This then requires an understanding of the liquid-to-glass transition and in particular an understanding of how chemical structure of the liquid affects the thickening process itself. In this project, visible light scattered by a glass-forming liquid is used to monitor this thickening process on a microscopic level. A series of glass-forming liquids are to be investigated in which the chemical structure can be systematically altered by either increasing or decreasing the average number of chemical bonds present in the liquid. With each modification of the structure, the corresponding changes in dynamical properties of the liquid will be assessed to test predictions of a simple model based upon the average number of bonds present. Graduate (MS) and undergraduate students will conduct this research as means of training the next generation of professional scientists.

技术摘要原则上，无定形的固相是所有液体特有的，尽管有些液体在冷却时会结晶。但是，在不同材料之间，液体在凝固之前变稠的方式大不相同。过去的研究表明，超冷的玻璃形成液体的动力学与其化学结构和热力学特性之间的动力学之间存在明确的联系。在这个项目中，正在应用动态光散射，拉曼光谱和差异扫描量热法，以探测液体动力学如何直接受到网络形成系统中创建的简单结构变化的影响。结果将构成目前可用的建议热力学模型（键模）的精确测试。工作将由研究生（MS）和本科生进行，提供动手研究经验以增加其科学教育。非技术抽象技术在利用材料的新特性方面蓬勃发展。其中，玻璃材料对许多最先进的设备具有独特的机械，光学和电气性能。但是，为了实现其潜力，必须从液态中巩固玻璃材料，而不会发生结晶。然后，这需要了解液体到玻璃的过渡，尤其是对液体化学结构如何影响增厚过程本身的理解。在这个项目中，使用玻璃形成液体散布的可见光用于在微观水平上监测这一增厚过程。将研究一系列玻璃形成的液体，其中可以通过增加或减少液体中存在的化学键的平均化学键数来系统地改变化学结构。随着结构的每次修改，将评估液体动力学特性的相应变化，以根据存在的平均键数测试简单模型的预测。研究生（MS）和本科生将进行这项研究，作为培训下一代专业科学家的手段。