Science of Co-Amorphous Molecular Glasses

共无定形分子玻璃是由两种或两种以上不同小分子组成的一类新型材料。将两种或两种以上的分子组合成扩展的固态材料，可以得到比单个组分系统具有更好性能的共非晶分子玻璃。通过研究分子大小、形状、柔韧性和化学相互作用位点等参数如何影响由不同类型分子二元混合物制成的玻璃的性质，北卡罗来纳州立大学的研究人员提供了对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分子玻璃在制药、能源学、农用化学品和个人护理产品中的应用。使用共无定形分子玻璃的优点包括，例如用于药品，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固态和材料化学项目支持，还包括对两名研究生和本科生进行玻璃化学和物理、热分析和流变学前沿研究的培训。此外，作为该奖项的一部分，教授。西蒙和麦肯纳为初中生组织了一个为期一周的软材料夏令营。它被称为“探索材料和回收”，并利用了由北卡罗莱纳州立大学工程学院工程广场（TEP）开发和管理的长期夏季工程营地项目。本研究由材料研究部固态与材料化学项目支持，主要研究范围广泛的二元共非晶分子玻璃，旨在为合理设计具有改进性能的新型玻璃固体开发框架。分子大小、形状和柔韧性在共非晶玻璃形成中的作用，以及在特定相互作用中强度和不匹配的重要性，通过量热法、流变学和光谱学对由药物材料、模拟能量学和小分子添加剂或辅料组合而成的玻璃进行了检查。在共非晶分子玻璃领域的主要悬而未决的问题，包括动力学，热力学和动力学性质，包括玻璃化转变温度（Tg），结晶速率和玻璃稳定性，是如何相互关联的，并受到分子结构和相互作用的影响。此外，热力学活度系数模型用于联系分子相互作用和在共非晶玻璃中经常观察到的Tg的协同增加。利用经典成核和生长动力学模型的扩展，在时间-温度转变（TTT）图的框架内对共非晶玻璃的抗结晶稳定性进行了建模和表征。这项工作的重要性在于为分子玻璃工程这一新兴领域提供了基础的新知识，有望促进新的玻璃固体的合理设计，这些玻璃固体可以根据给定功能的需求进行设计。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.