Topologically Frustrated Polymer Dynamics and Phase Behavior of Polyzwitterions

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

NON-TECHNICAL SUMMARY Large molecules capable of carrying electrical charges are ubiquitous ever since life began on Earth. Such macromolecules are also vital in formulating environmentally friendly materials to guard global sustainability. However, experiments during the past century have shown that these molecules behave in mysterious ways that are difficult to understand and predict. These charged macromolecules in any system do not function alone, but all of them work together in collaborative manners. A fundamental understanding of such large scale cooperativity among many molecules is one of the grand challenges in physical and biological sciences. Towards mitigating this challenge, the PI will formulate a fundamental understanding of how electrically charged macromolecules move around in crowded electrolyte solutions, and how to facilitate them to form desirable structures toward novel water-based materials for societal benefits. In addition, the proposed activities include strong support of diversity and training a new generation of scholars and enable their future participation in industries on water-based materials and maintenance of global sustainability. TECHNICAL SUMMARY The PI proposes experiments and theoretical developments to investigate hierarchical structure and dynamics of charged macromolecules, topologically frustrated non-diffusive dynamical state, coacervate gel composites, and assembly and phase diagrams for polyzwitterions, by combining light scattering, neutron scattering, fluorescence spectroscopy, fluorescence microscopy, impedance spectroscopy, rheology, single molecule electrophoresis, statistical mechanics, field theory, and several multi-scale simulation techniques. Specifically, the proposal addresses (a) the nature and origin of the newly discovered topologically frustrated dynamical state of polymers, and its transition into the other conventional dynamical modes, such as the Rouse-Zimm and reptation, (b) non-equilibrium forces to control formation of coacervate gel composites, and (c) dipolar interactions to understand assembly and phase behaviors of polyzwitterions. This project is aimed at understanding the intricate behaviors of charged macromolecular systems, and discovering new conceptual models for structure, dynamics, and transport in aqueous charged polymer systems. A fundamental understanding of the behavior of this important class of materials will help to design novel water-based polymeric materials to secure global sustainability with enhanced benefits to society. Training of graduate students and postdocs in this challenging research area is also an important component of the proposed activity. . 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.