Harnessing Complex Macromolecular Conformations
Seeks to understand the impact of chain conformations on macroscopic responses to applied forces and emphasizes topics related to the non-equilibrium behavior of polymers.
After a century of macromolecular science, which originated from the “polymer hypothesis” put forth by Hermann Staudinger, control and characterization of equilibrium chain conformations has become feasible. A number of advances have been made in connecting chain configurations and conformations to macroscopic properties using the concepts of Gaussian chain statistics, entanglements, and the collapse of chains in solvent media. In contrast, chain conformations under non-equilibrium conditions that result from either the presence of applied forces or processing protocols are less emphasized and not yet understood. Advances in synthetic polymer chemistry and topology control have enabled improved physical models beyond scaling with chain length and interaction parameters in both solution and bulk form; however, interphase and interfacial considerations are important for numerous “real world” and industrial applications that exist in mostly non-equilibrium conditions. Due to a limited number of studies probing chain conformations in non-equilibrium conditions, their connections with macroscopic responses remain unclear. In this Theme, we seek to bridge this gap in our understanding by focusing on the overarching goal of connecting non-equilibrium chain conformations to macroscopic responses using state-of-the-art synthesis, characterization, and modeling. To achieve our overarching goal, three specific aims will be pursued:
- Understanding structural and polarization dynamics in dipolar polymers: Connections between non-equilibrium chain conformations and their responses can be investigated by designing experiments with carefully chosen polymers (non-polar and polar). These experiments and complementary simulations can unveil the role of entropy production by using electrostatics as a gauge for tailoring and measuring responses to applied fields, allowing us to explore the presence and tunability of these responses via small molecule and ion intercalation.
- Understanding topological effects in polymers and block copolymers: Advances made in synthesizing topologically complex macromolecules (geometrical topology) and compositions such as graft copolymers and knotted polymers provide a library of materials in which topological effects can be tuned in a facile manner by varying chain architecture and measuring responses to various non-equilibrium conditions.
- Understanding processing effects including solvent evaporation, reactions, thermal treatment, and mechanical deformation on polymer properties and responses: Polymer non-equilibrium states in real-time will be studied to enable correlating macromolecular properties during a process, a key toward property optimization in technologies involving 3D printing.
These three aims will provide critical understanding of entropy-driven processes that are key toward designing processing pathways and macromolecular architectures for accessing metastable morphologies, e.g., a materials-by-design concept for functional soft materials that operate synchronously with processing conditions.