CAREER: Fundamentals of Conformational and Surface Water Dynamics in Supramolecular Nanofibers

麻省理工学院的Julia Ortony教授获得了化学系大分子、超分子和纳米化学项目颁发的这一职业奖，正在研究两亲性分子在水中的自组装。两亲性分子兼具亲水性和亲脂性。它们通常存在于肥皂和洗涤剂中，是细胞膜的主要成分，在细胞膜中，单个分子可以在细胞成分内部和之间自由移动。在这项研究中，新的两亲分子被用来创建自组装纳米结构，然而，在这些纳米结构中，单个分子被固定在适当的位置。然后，使用复杂的技术仔细研究这些系统的分子运动，这些技术提供了关于众所周知的材料芳纶(用于防弹背心)中的分子和地表水运动的信息。与该奖项相关的研究有可能促进对生物分子表面化学反应以及结合和折叠事件的基本了解。这项工作为不同群体的学生提供超分子化学和材料科学方面的培训和教育。教育活动的重点是材料化学本科核心课程的现代化，为本科生设计一门新的高级分子材料课程，为研究生开设一门分子材料表征课程。Ortony教授还计划继续参加几项导师活动，如麻省理工学院的女性MatSci小组、麻省理工学院-道氏访问计划、为工程领域的女性提供本科生咨询，以及麻省理工学院毕业生材料委员会。这项研究的重点是设计和合成一种新的两亲性分子平台，它在水中自发地自组装成纳米纤维。这种自组装平台表现出非凡的机械性能，这是在最初的分子设计中编程实现的强烈而集体的分子间氢键的结果。在第一个目标中，两亲分子的合成具有不同的表面电荷和分子柔性。第二个目标是通过电子顺磁共振(EPR)来量化纳米纤维的内部构象动力学，以及通过统计形貌分析来量化纳米纤维的柔韧性和强度。最后一个目标集中在了解分子特征、水动力学和来自系链官能团的表面识别事件之间的关系。这项研究产生的基础知识有可能显著有助于对超分子组装、水中纳米结构的动力学以及界面上的识别事件的总体理解。这一奖项反映了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。

With this CAREER Award from the Macromolecular, Supramolecular, and Nanochemistry Program in the Chemistry Division, Professor Julia Ortony at Massachusetts Institute of Technology is studying self-assembly of amphiphilic molecules in water. Amphiphilic molecules possess both water-loving and fat-loving properties. They are typically found in soaps and detergents, and are the main component of cell membranes, where individual molecules are free to move within and between cellular components. In this research, new amphiphiles are used to create self-assembled nanostructures, however, in these nanostructure the individual molecules are fixed in place. The molecular motion of these systems is then carefully studied using sophisticated techniques that provide information about the motions of molecules and surface water in a well known material, Kevlar (used for bullet-proof vests). Research associated with this award has the potential to advance fundamental understanding of chemical reactions at surfaces, and binding and folding events in biological molecules. This work provides training and education to a diverse group of students in supramolecular chemistry and materials science. Educational activities focus on the modernization of the materials chemistry undergraduate core curriculum, the design of a new advanced molecular materials course for undergraduates, and teaching of a molecular materials characterization course for graduate students. Professor Ortony also plans to continue her participation in several mentorship activities such as MIT's Women of MatSci group, MIT-DOW ACCESS program, undergraduate advising for women in engineering, and the MIT Graduate Materials Council. This research is focused on the design and synthesis of a new platform of amphiphilic molecules that spontaneously self-assemble into nanofibers in water. This self-assembly platform exhibits extraordinary mechanical properties that results from strong and collective intermolecular hydrogen bonding programmed into the initial molecular design. In the first objective, amphiphiles are synthesized with varying surface charge and molecular flexibility. The second objective focuses on quantifying nanofiber internal conformational dynamics by electron paramagnetic resonance (EPR) and nanofiber flexibility and strength by statistical topographical analyses. The last objective concentrates on understanding the relationship between molecular features, water dynamics, and surface recognition events from tethered functional groups. The fundamental knowledge generated by this research has the potential to significantly contribute to the general understanding of supramolecular assembly, the dynamics of nanostructures in water, and recognition events at interfaces.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.