Spatial Organization of Ions in Supramolecular Nanostructures

The spatial control of ions around synthetic nanostructures remains a great challenge in the design of functional supramolecular polymers. We are therefore interested in developing new design principles for the organization of ions in supramolecular polymers. Specifically, we propose to explore the effect of ions on self-assembled nanostructures and how these effects can tune the shape and dimensions of these structures, the conductivity, and the ion mobility. We will investigate the effects of simple salts at different concentrations as well as more complex ion dopants like those based on ionic liquids. In these systems, the supramolecular structures are determined by the presence of specific ions and can also spatially organize those ions through their architectures. The final goal will be to tune the ion mobility (ionic conductivity) based on the supramolecular structure and to understand if such supramolecular structures can buffer different types of ions. This is of crucial importance for several types of biological processes (cells maturation, therapeutic procedures, etc.) and we believe that at the end of the project we will be able to control and display different types of ions on supramolecular structures that could be used in different biological processes. The intellectual merit of the proposal lies in a simultaneous experimental and computational approach to studying spatial organization of ions in and around supramolecular nanostructures. The first project probes how added ions interact with supramolecular polymers to create novel structures. This work will contribute to a fundamental understanding of intermolecular interactions in these systems. The second project explores the effects of adding ion dopants that can better penetrate and interact with the nanostructures, resulting in even greater control over the distribution of ions in the system. Together these projects are expected to greatly increase our understanding of the balance of forces undergirding the assembly of amphiphilic molecules into functional nanostructures in water. One reason the proposed work will have broader impact is because the experimental exploration of such hybrid systems will teach us greatly about the formation of complex structures in biology in which formation of supramolecular structure “begins” with covalent polymers (e.g., proteins, nucleic acids, polysaccharides). In this context it will contribute to the multi-dimensional education of graduate students and postdoctoral fellows in chemistry and materials science, seeking inspiration for their research in biological systems. Another important reason why the research has broader impact on education is the fact that it is a risky exploration that attempts to innovate beyond traditional approaches to polymer science. We suggest that the proposed research has therefore a great deal of potential for unexpected discoveries, which always motivate young scientists and impact their education greatly. All this is particularly important in the training of students from underrepresented groups who require strong motivation.