Supramolecular polymers represent a new generation of polymeric materials, offering advantageous properties in processing, self-healing, and recycling, and have important technological applications as both electronically and biological active materials. Possessing the fundamental knowledge that would enable the precise tuning of the mechanical properties at the polymer molecular and network level could lead to a significant shift in the way that supramolecular materials are designed. This project is in the general area of Computationally and Data-Driven Materials Research (CDMR). It aims to develop an in-depth understanding of the various factors that affect the cooperative association of small molecular building units into supramolecular polymers, and to use the knowledge gained to achieve precise control over the mechanical properties of individual polymers as well as their 3D networks. A combined use of experimental and computational methodologies will help elucidate the key features of these building units for precise control over the mechanical properties of the resulting supramolecular polymers. Prediction of the pathway of self-assembly is proposed with molecular modeling at multiple length-scales. Knowledge generated from this work will impact the development of advanced materials for applications in organic electronics, where the polymer length and inter-polymer associations are important, and in regenerative medicine, which requires biologically active hydrogels with defined stiffness. The two PIs bring complementary experimental and theoretical/computational expertise to this integrated project and are committed to providing a broad educational experience at all levels.
PART 2: TECHNICAL SUMMARY
The formation of ordered supramolecular polymers (SPs), utilizing small molecular building units that can assemble into highly ordered and discrete one-dimensional (1D) nanostructures, has led to the development of functional supramolecular materials. This project is in the general area of Computationally and Data-Driven Materials Research (CDMR) and is focused on in-depth understanding of the various factors that affect the cooperative association of small molecular building units. It aims to design and synthesize a series of small-molecule mikto-arm star building units (MASBUs) possessing three distinct functional arms (two hydrophobic and one hydrophilic), and to elucidate the key molecular design features that define their growth kinetics and eventual mechanical properties of ordered SPs. A combined experimental and computational approach with an active feedback mechanism will be applied to correlate the sequential variation of each arm with the mechanical properties (persistence length, contour length, bundling) of the resulting SPs and their networks. Specifically, Objectives 1 and 2 will focus on the synthesis and study of MASBUs possessing isomeric hydrocarbons and pi-conjugated segments, respectively, aiming to determine the relationship between the internal packing order and the persistence length. Objective 3 aims to establish a correlation between the growth kinetics and the contour length by varying the strength of associative interactions within a peptide segment capable of forming intermolecular hydrogen bonding. Objective 4 will attempt to identify the key factors that determine the bulk mechanical properties of the supramolecular networks formed by the assembled SPs, in particular looking at the effect of the persistence and contour length and also the SP bundling. A successful outcome will lead to significant advances in our fundamental knowledge of structure-property relationships in ordered SP systems, and could have a substantial impact on the creation of supramolecular materials. The two PIs bring complementary experimental and theoretical/computational expertise to this integrated project and are committed to providing a broad educational experience at all levels.
