Charged polymers are used in a wide array of applications, ranging from battery and fuel cell electrolytes to viscosity modification and encapsulation in food products to advanced stimuli-responsive materials. Charged polymers are also ubiquitous in biological materials – most biomacromolecules are charged, which is a crucial aspect of their function. Understanding the physical properties of these systems is thus profoundly important to developing new materials that harness the features of complex biological systems (hierarchical structure, specificity, etc.) for the wide array of applications that already feature charged polymers (and more!).
We are interested in a variety of charged polymer materials, including complex coacervates, polymers in ionic liquids, and melt polyelectrolytes. In particular, we are using a combination of simulation and theory to address challenges such as how effects such as charge correlations, molecular shape, polymer monomer sequence, high charge densities, and chain architecture dictate macroscopic material properties. Our work aspires to reveal new ways to manipulate and tune materials using charges. We are pioneering new ways to use polymers and charges to develop materials capable of emulating biology and relevant to applications ranging from advanced stimuli-responsive systems to materials for energy applications.
Systems comprised of oppositely-charged polymers in the presence of high salt concentrations form ‘complex coacervates’. These systems resemble a gel with transient, electrostatically-driven crosslinks. This is an emerging motif used in self-assembled materials as well as a physical environment resembling biological systems. Understanding the equilibrium and dynamic properties of coacervates will lead to new paradigms in molecular-level material design.
Ionic liquids are candidates for electrolytes in energy applications, and have been used in material self-assembly. They are also known to have surprising phase behaviors when mixed with polymers. We desire a fundamental physical understanding of these systems – we would like to be able to guide experimentalists as they explore the vast parameter space of these complicated, charged materials.