GOALI: Crystallization of Organic Glasses

目标：有机玻璃的结晶

• 批准号: 0907031
• 负责人: Lian Yu
• 金额: $ 78.29万
• 依托单位: University of Wisconsin-Madison
• 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: 2009-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907031&HistoricalAwards=false
• 关键词: GOALI; Crystallization; Organic; Glasses

DMR 0907031 GOALI: Crystallization of Organic GlassesTECHNICAL SUMMARY:In this collaborative project, Profs. Lian Yu, Mark Ediger, and Juan de Pablo of the University of Wisconsin ? Madison, Dr. Geoff Zhang of Abbott Laboratories, and their research student colleagues will investigate the crystallization of organic glasses. Glasses are liquids that are too cold to flow. According to the current view that crystallization is controlled by diffusion, organic glasses should not crystallize readily. Yet recent work has shown that many do crystallize, sometimes at rates 105 times faster than predicted by the standard models. This study concerns two modes of crystal growth activated near the glass transition temperature: a bulk mode and a surface mode. Both growth modes are too fast to be controlled by bulk diffusion. The team will test the hypothesis that molecular motions native to the glassy state can cause crystal growth, without involving substantial bulk diffusion, if sufficient similarity exists between the crystal and liquid structures. They will determine whether crystal growth in the glassy state becomes faster if bulk molecular motions are amplified with an external field. They will study whether surface-enhanced crystal growth results from surface-enhanced molecular mobility. Surface diffusion coefficients of organic glasses will be measured for the first time by the method of surface grating decay and correlated with surface crystal growth rates. The project will examine what properties of coating materials are important for suppressing surface crystallization. Computer simulations will identify the underlying mechanisms of bulk and surface crystal growth of organic glasses. For each growth mode, a screening experiment will be performed to assess its generality and polymer additives will be added to perturb it for further insights on its mechanism and control.NON-TECHNICAL SUMMARY:Crystallization influences almost every aspect of modern technology. While it has been extensively studied for hard inorganic materials, crystallization remains poorly understood for organic materials. In this collaborative project, a team of academic and industrial researchers will seek to understand the crystallization of organic glasses. Glasses are liquids that are too cold to flow; they are the preferred materials for many applications, ranging from pharmaceutical development to telecommunication. The team will study the activation of new, fast modes of crystal growth as a liquid becomes a glass and the control of these new modes in developing amorphous materials. The results of this research will benefit scientists in a range of fields where crystal growth is important; for example, amorphous pharmaceuticals and organic electronics. The enormous potential of using amorphous solids to enhance the bioavailability of poorly soluble drugs has motivated Abbott to partner with the University of Wisconsin in this project. It is a unique advantage that the Chicago-based Abbott is only a short distance away from Madison, enabling close interactions between the collaborators. Graduate and undergraduate students will benefit from the multi-disciplinary nature of this project, having significant exposure to experiments and simulations, crystals and glasses, high and low molecular weight organic materials, and both industrial and academic research labs. Personnel supported by this grant will work with UW-Madison?s Pre-college Enrichment Opportunity Program for Learning Excellence (PEOPLE), which has a proven record of increasing the enrollment of minority and low-income high school students in colleges and universities. This program provides experiences that help students to become scientifically literate citizens and encourages them to consider careers in science and engineering.

目标：有机玻璃的结晶技术摘要：在这个合作项目中，威斯康星大学的廉宇、马克·艾迪格和胡安·德·巴勃罗？麦迪逊、雅培实验室的杰夫·张博士和他们的研究生同事将研究有机玻璃的结晶。玻璃是一种太冷而不能流动的液体。根据目前的观点，结晶是由扩散控制的，有机玻璃不应该容易结晶。然而，最近的研究表明，许多物质确实会结晶，有时结晶速度比标准模型预测的快105倍。本研究涉及在玻璃化转变温度附近激活的两种晶体生长模式：体模式和表面模式。这两种生长模式都太快了，无法由体扩散控制。该团队将测试一个假设，即如果晶体和液体结构之间存在足够的相似性，玻璃态的分子运动可以导致晶体生长，而不涉及大量扩散。他们将确定如果外场放大大块分子的运动，晶体在玻璃态下的生长是否会更快。他们将研究表面增强的晶体生长是否源于表面增强的分子迁移率。本文将首次用表面光栅衰减法测量有机玻璃的表面扩散系数，并将其与表面晶体生长速率相关联。该项目将研究涂层材料的哪些特性对抑制表面结晶很重要。计算机模拟将确定有机玻璃的体积和表面晶体生长的潜在机制。对于每种生长模式，将进行筛选实验以评估其普遍性，并添加聚合物添加剂对其进行扰动，以进一步了解其机制和控制。结晶几乎影响了现代技术的每一个方面。虽然对硬质无机材料的结晶已经进行了广泛的研究，但对有机材料的结晶仍然知之甚少。在这个合作项目中，一个由学术和工业研究人员组成的团队将寻求理解有机玻璃的结晶。玻璃是一种太冷而不能流动的液体；它们是许多应用的首选材料，从制药开发到电信。该团队将研究在液体变成玻璃时晶体生长的新快速模式的激活，以及在开发非晶材料时对这些新模式的控制。这项研究的结果将使许多领域的科学家受益，其中晶体生长是重要的；例如，无定形药品和有机电子产品。利用无定形固体提高难溶性药物的生物利用度的巨大潜力促使雅培与威斯康星大学合作开展该项目。这是一个独特的优势，总部位于芝加哥的雅培离麦迪逊只有很短的距离，使合作者之间的密切互动。研究生和本科生将受益于这个项目的多学科性质，有大量的接触实验和模拟，晶体和玻璃，高分子量和低分子量有机材料，以及工业和学术研究实验室。该基金支持的人员将与威斯康星大学麦迪逊分校合作。美国的“大学前强化学习机会计划”（PEOPLE），该计划在提高少数族裔和低收入高中学生的大学入学率方面有着良好的记录。这个项目提供了帮助学生成为具有科学素养的公民的经验，并鼓励他们考虑从事科学和工程方面的职业。