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

University Of California-San Diego, La Jolla CA

Investigators

Abstract

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.