Science of Co-Amorphous Molecular Glasses

非技术综述钴非晶态分子玻璃是一种由两种或两种以上不同类型的小分子组成的新型材料。将两种或两种以上这种类型的分子组合成扩展的固态材料，可以得到具有比单独组成系统更好性能的共非晶态分子玻璃。北卡罗来纳州立大学的研究人员通过研究分子大小、形状、柔韧性和化学相互作用位置等参数如何影响由不同类型分子的二元混合物制成的玻璃的性能，提供了对共非晶态分子玻璃的基本理解。这些见解和新材料有可能推动共非晶态分子玻璃在制药、能量学、农用化学品和个人护理产品中的使用。使用共非晶态分子玻璃的优点包括例如用于制药的高生物利用度和储存期间的高稳定性。该项目由材料研究部的固态和材料化学项目支持，还包括培训两名研究生和本科生研究人员，从事玻璃化学和物理、热分析和流变学方面的尖端研究。此外，作为这个奖项的一部分，教授。西蒙和麦肯纳为初中生组织了为期一周的软材料夏令营。它被称为“探索材料和回收”，并利用了由北卡罗来纳州立大学工程学院工程学院(TEP)开发和管理的长期夏季工程夏令营计划。技术概述这项研究得到材料研究部固态和材料化学计划的支持，重点研究范围广泛的二元共非晶态分子玻璃，以开发一个框架，用于合理设计具有改进性能的新型玻璃固体。通过量热法、流变学和光谱分析，研究了分子大小、形状和柔韧性对共非晶态玻璃形成的作用，以及在特定相互作用中强度和失配的重要性。讨论了共非晶态分子玻璃领域中尚未解决的主要问题，包括动力学、热力学和动力学性质，包括玻璃化转变温度(Tg)、析晶速率和玻璃稳定性，它们是如何相互联系和受分子结构和相互作用影响的。此外，热力学活度系数模型被用来关联分子间的相互作用和在非晶态玻璃中经常观察到的Tg的协同增加。在时间-温度-转变(TTT)图的框架内，利用经典形核和生长动力学模型的扩展，对非晶态玻璃的抗晶化稳定性进行了模拟和表征。这项工作的重要性是为分子玻璃工程这一新兴领域提供基本的新知识，预计将促进合理设计可根据给定功能的需求进行工程的新玻璃固体。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical SummaryCo-amorphous molecular glasses are a new class of materials that are composed of two or more types of different small molecules. Combining two or more of these types of molecules into extended solid-state materials leads to co-amorphous molecular glasses that have better properties than the individual component systems. By investigating how parameters such as molecular size, shape, flexibility, and chemical interaction sites impact the properties of glasses made from binary mixtures of different types of molecules, researchers at North Carolina State University provide a fundamental understanding of co-amorphous molecular glasses. These insights and novel materials have the potential to advance the use of co-amorphous molecular glasses in pharmaceutics, energetics, agrichemicals, and personal care products. Advantages of using co-amorphous molecular glasses include, for example for pharmaceutics, high bioavailability and high stability during storage. The project, which is supported by the Solid State and Materials Chemistry program in the Division of Materials Research, also includes training of two graduate students and undergraduate researchers in cutting-edge research in glass chemistry and physics, thermal analysis, and rheology. Additionally, as part of this award, Profs. Simon and McKenna organize a one-week-long soft materials camp for junior high school students. It is called "Exploring Materials and Recycling" and leverages the longstanding summer engineering camp program developed and managed by The Engineering Place (TEP) of the North Carolina State University College of Engineering. Technical SummaryThis research, which is supported by the Solid State and Materials Chemistry program in the Division of Materials Research, focuses on a wide range of binary co-amorphous molecular glasses in order to develop a framework for the rational design of new glassy solids with improved properties. The role of molecular size, shape, and flexibility on co-amorphous glass formation, as well as the importance of the strength of and mismatches in specific interactions, are examined by calorimetry, rheology, and spectroscopy for glasses created by combinations of pharmaceutical materials, mock energetics, and small molecule additives or excipients. Major unanswered questions in the field of co-amorphous molecular glasses are addressed, including how dynamic, thermodynamic, and kinetic properties, including the glass transition temperature (Tg), crystallization rates, and glass stability, are interrelated and influenced by molecular structure and interactions. In addition, thermodynamic activity coefficient models are used to relate the molecular interactions and the synergistic increases in Tg that are often observed in co-amorphous glasses. The stability of the co-amorphous glass against crystallization is modeled and characterized in the framework of the time-temperature-transformation (TTT) diagram using extensions of classical models of nucleation and growth kinetics. The importance of the work is in providing fundamental new knowledge for the nascent field of molecular glass engineering that is anticipated to facilitate the rational design of new glassy solids that can be engineered on demand for a given function.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.