Joint U.S./German Investigation of Extraordinarily Stable Glasses by Nanocalorimetry

近年来的研究表明，用物理气相沉积法可以制备出高密度、高稳定性的有机玻璃。这些玻璃可以被认为是“超老化”的，因为它们具有传统方法需要数千年或更长时间才能生产的特性。这些材料独特地允许探索潜在能量景观的下游，这些潜在能量景观支配着无定形系统的动力学和热力学。最稳定的玻璃和那些最有可能用于应用将是亚微米薄膜。新兴的纳米量热技术是唯一具有足够灵敏度的方法来测量热容并确定这种稳定玻璃在能源景观中的位置。我们建议开发一种结合扫描/AC纳米量热法的气相沉积玻璃和其他凝聚相系统的原位表征方法。我们将气相沉积最佳表征的有机玻璃形成剂（邻三联苯、甘油和亚磷酸三苯酯）。这些活动将导致理解的脆弱性，氢键和分子结构如何影响形成稳定的玻璃的能力，更一般地理解沉积温度和无定形包装之间的关系。该项目只能通过将威斯康星州麦迪逊集团的稳定玻璃专业知识与罗斯托克集团的纳米量热专业知识相结合来实现其目标。学生的交流和网络基础设施的使用将是德国/美国合作成功的关键。

Recent work has shown that organic glasses with remarkably high density and high stability can be prepared by physical vapor deposition. These glasses can be regarded as "super-aged" as they have properties that would require thousands of years or more to produce by conventional methods. These materials uniquely allow the exploration of the lower reaches of the potential energy landscape that governs the dynamics and thermodynamics of amorphous Systems. The most stable glasses and those most likely to be used in applications will be submicron films. The emerging technology of nanocalorimetry is the only method with sufficient sensitivity to measure the heat capacity and determine the position of such stable glasses on the energy landscape. We propose to develop a combined scanning/AC nanocalorimetry method for in situ characterization of vapor-deposited glasses and other Condensed phase Systems. We will vapor-deposit the best-characterized organic glassformers (o-terphenyl, glycerol, and triphenylphosphite). These activities will lead to an understanding of how fragility, hydrogen bonding, and molecular structure affect the ability to form stable glasses and more generally to an understanding of the relationship between deposition temperature and amorphous packing. This project can only achieve its objectives by combining the stable glass expertise of the Madison, WI, group with the nanocalorimetry expertise of the Rostock group. The exchange of students and the use of cyberinfrastructure will be critical to the success of this German/U.S. collaboration.