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

最近的工作表明，通过物理气相沉积可以制备出密度和稳定性都非常高的有机玻璃。这些玻璃可以被认为是“超龄”的，因为它们的性能需要数千年或更长时间才能用传统方法生产。这些材料独一无二地允许探索控制非晶态系统动力学和热力学的势能图景的下游。最稳定和最有可能用于应用的玻璃将是亚微米薄膜。新兴的纳米量热技术是唯一一种具有足够灵敏度的方法来测量热容并确定这种稳定的玻璃在能源景观上的位置。我们建议开发一种扫描/交流纳米量热相结合的方法来原位表征气相沉积玻璃和其他凝聚相系统。我们将用气相沉积的方法制备性能最好的有机玻璃成型剂(邻三苯基、甘油和亚磷酸三苯酯)。这些活动将导致理解脆性、氢键和分子结构如何影响形成稳定玻璃的能力，更广泛地说，有助于理解沉积温度和无定形堆积之间的关系。该项目只有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，才能实现其目标。学生的交换和网络基础设施的使用将是这次德美合作成功的关键。

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.