(4hn) Pushing the Frontier of Ionic Polymer Self Assembly and Processing | AIChE

(4hn) Pushing the Frontier of Ionic Polymer Self Assembly and Processing


Fang, Y., University of Chicago
Medina Jimenez, C., University of Chicago
Rumyantsev, A., University of Chicago
De Hoe, G., University of Chicago
De Pablo, J., University of Wisconsin-Madison
Tirrell, M. V., University of Chicago
Composites exhibiting well-defined hierarchical lengthscales at the level of macro- and supramolecular structure are frequently found in nature. Such definition at the nano- to macroscale produces intricate materials where properties are controlled at the global level as well as spatially manipulated across the bulk. My laboratory will design macromolecules innovating and employing a broad palette of synthetic methods to exploit strategically-positioned motifs in their bottom-up assembly directed by synergistic non-covalent interactions. The integration of powerful synthetic methodology and molecular design guided by emerging theory with processing strategies will position my lab to construct materials for sustainability and human health with exceptional control over properties and functions.

Research Interests
Proposal I – Structure–Property–Processing Relationships of Charge-Complexed Polymer Blends
Charge-complexed polymers in the melt and solid state have tremendous potential in energy, filtration, and biomedical applications but bulk structure–property–processing relationships have not been explored as thoroughly as solution complexes. My group will systematically decouple individual parameters that direct material structure and properties by studying libraries of well-defined polymers. We will optimize and innovate synthetic methodology to access desirable and unprecedented macromolecular structures. Molecular design parameters will be guided by emerging theory, for example, exploring morphologies recently described for incompatible polyelectrolyte complex blends. A powerful combination of small-angle scattering and rheology methods will provide insights into morphology and mechanical properties to inform guidelines for processing parameters.

Proposal II – Sustainable Barrier Materials for Food Packaging Applications
Plastic barrier laminates are vital in food packaging where diffusion of gases, liquids, and oils must be thwarted to protect contents or bulk packaging materials (e.g., cardboard take-out containers) from spoilage or mechanical deterioration, respectively. Polyethylene laminates are the predominant product on the market which offer little opportunity for reprocessing or degradation. Particularly for plastics contaminated with organic waste, composting upon end-of-life is a substantive option in line with the circular economy. My group will fabricate lamellar thin films from charge-complexed, compostable polymers with alternating polyelectrolyte complex and neutral domains, to stymie diffusion of non-polar (e.g., grease, O2) and polar (e.g., water) substances, respectively. This strategy circumvents laborious layer-by-layer deposition, capitalizes on the combined barrier and mechanical properties of neutral and ionically crosslinked layers, and offers tunable biodegradation as a function of macromolecular chemistry and sequence.

Proposal III – Additive Manufacturing of Functionally Graded Materials
Natural materials commonly exhibit mechanical property gradients, which afford them remarkable load bearing capability and advanced functionality. For example, certain marine organisms have structural elements exhibiting a several order of magnitude range of modulus over millimeter lengthscales. Synthetic materials replicating such sophisticated designs are still in their infancy. Additive manufacturing is uniquely positioned to fashion functionally graded materials via multi-nozzle deposition. My group will take advantage of the whole palette of non-covalent interactions in complex blends integrated with the dynamic variation of local composition afforded by additive manufacturing to push the frontiers of bioinspired materials that will revolutionize the state-of-the-art of biomedical products.

Teaching Interests
I am well-prepared to teach core classes in chemistry and materials science as well as select courses in chemical engineering. Courses that I am particularly interested in teaching include organic and organometallic chemistry, polymer chemistry, and polymer physics. I am passionate about course design and would like to develop a graduate level course in bioinspired materials. During my graduate career I gained extensive experience teaching courses in organic chemistry, polymers, and microstructural characterization of materials. My contributions to teaching have been recognized by an outstanding teaching award in polymers. During my time as postdoctoral fellow at the University of Chicago I have helped to develop and teach an introduction to molecular engineering short course to a diverse body of students from the City Colleges of Chicago interested in STEM careers. I furthermore particularly enjoy mentoring students in the research setting. Currently I mentor two graduate students and have mentored three undergraduate and two graduate students in the past.

I received a Ph.D. in materials science and engineering at the University of Minnesota in 2018 under the guidance of Prof. Marc Hillmyer. At Minnesota I worked on the divergent polymerization of cyclic hemiacetal esters for the production of hydrolytically sensitive poly(hemiacetal esters) and polyesters. I then moved to the University of Chicago to join Prof. Matthew Tirrell’s group to gain expertise in the synthesis, characterization, and physics of charged polymers. My ongoing work can be broken down into three themes: 1) the synthesis of high molar mass polyelectrolytes to corroborate scaling laws for weakly charged polyelectrolyte coacervates, 2) the structural and rheological characterization of polyelectrolyte coacervates, and 3) the synthesis and study of well-defined polyampholytes and polyzwitterions in solution.