MSE Seminar: “Advancing Fundamentals of Polyelectrolyte Physics with Precise Chemistry”

Details

Angelika Neitzel, Ph.D.

Postdoctoral Fellow, Pritzker School of Molecular Engineering
University of Chicago

Angelika Neitzel received a Ph.D. in Materials Science and Engineering at the University of Minnesota under the guidance of Professor Marc Hillmyer. At Minnesota, she worked on the ringopening polymerization of cyclic hemiacetal esters, which yields hydrolytically and thermally degradable polymers. She provided a detailed understanding of the mechanism, kinetics, and thermodynamics of the polymerization of these novel monomers and demonstrated their use as building blocks for the synthesis of polyhemiacetal esters and polyesters.

Following her studies at Minnesota, she moved to the University of Chicago to join the research group of Professor Matthew Tirrell. In the Tirrell group, Angelika took on the synthesis and characterization of charged polymers and developed a passion for their physics. Her work spans from the structure and phase behavior of synthetic polyelectrolyte complexes to the chain statistics of synthetic polyzwitterions.

Abstract

Charged polymers are abundant in nature and their electrostatic interactions provide rich physics that pose many open questions. For example, solutions of oppositely charged polymers spontaneously form soft condensed phases known as polyelectrolyte complexes (PECs). These intriguing structures are found in natural systems such as membraneless compartments inside cells and advanced functional and responsive materials (e.g., underwater adhesives used by mussels and sandcastle worms). The ion pairs between polymer chains in PECs act as physical crosslinks, and one of the most powerful methods to alter PEC properties is by tuning their ionic crosslinking density.

In this talk, I will discuss our work employing a well-defined, modular polyether platform for the synthesis of homologous polyanions and polycations to quantify PEC properties and phase behavior across a broad range of polyelectrolyte linear charge densities (i.e., PEC ionic crosslinking densities). Our experimental results are compared to available scaling theory and molecular dynamics simulations to rationalize salient features of the binodal phase diagrams.

Finally, I will give a brief overview of ongoing work leveraging our synthetic system to further explore the structure and dynamics of PECs using microscopy, small-angle scattering, and rheological methods.