CBE Seminar (Zoom): Manipulating Architecture and Mechanics via Bio-inspired Design

Registration Link for Non-UCI Persons: https://forms.gle/marCSGBY9RUoXUSG9

Abstract: Taking cues from biological systems, we are interested in understanding the design rules employed by nature and applying these strategies to the development of mechanically-enhanced and tunable materials. With a bio-inspired mechanical framework, our research projects in responsive composites and peptidic-hybrid assemblies.

Motivated by plant muses, we have explored the fabrication of responsive composite systems utilizing high modulus, electrospun and low molecular gelators (LMWGs) as fillers. Here, we discuss new insights into hygromorphic (e.g. hydration/humidity) response in composites utilizing concepts of interfacial assembly, transport, bias and orientation learned from plant muses. We have fabricated a strategically interfaced hygromorphic composite utilizing an active electrospun filler and a passive, low molecular weight gelator layer in an elastomeric matrix. The impact of material parameters on water front progression and actuation were probed theoretically and experimentally in their design. Via this approach, preferential coiling was observed. However, two challenges were encountered due to the isotropic nature of the electrospun mat: (1) slow response times, and (2) non-uniformity in hydration-induced response. To overcome these limitations, we explored the impact of the alignment of the electrospun fibers as a handle to control rate of hydration and program shape change. These engineered hygromorphic composites exhibited predictable curvature and much faster response times (2-3 min). It is anticipated that these water-responsive systems may have unique applications in therapeutic delivery and chemical/biological protection. 

Inspired by spider silk, we have designed a series of polymer-peptide polyurethane/ureas to explore the hierarchical arrangement critical to energy absorption and mechanical enhancement. We have developed chain-extended and non-chain extended peptide-polyurea hybrids with tunable secondary structure, modulating extensibility, toughness and stiffness. A molecular design strategy that overlays a covalent and physically crosslinked architecture in these hybrids has also been investigated, demonstrating that physical constraints in the network hybrids influences hydrogen bonding and morphology. Additionally, tailored physical associations within the soft and hard phases were engineered as a function of peptide content, leading to a rheological response dictated by block ordering and highlighting their potential as structural and injectable hydrogels. Recently, we utilized these hybrids to design thermoresponsive shape memory elastomers with shape fixity and shape recovery tuned by secondary structure. New efforts in hybrid systems with adaptable mechanics also are highlighted via the incorporation of nanofillers. 

Bio: LaShanda T. J. Korley is a Distinguished Professor in the Departments of Materials Science & Engineering and Chemical & Biomolecular Engineering at the University of Delaware (UD). Previously, she held the Climo Associate Professorship of Macromolecular Science and Engineering at Case Western Reserve University, where she started her independent career in 2007. Korley is the director of the recently awarded Energy Frontier Research Center – Center for Plastics Innovation (CPI) funded by the Department of Energy and the co-director of the recently announced Materials Research Science and Center – UD Center for Hybrid, Active and Responsive Materials (UD CHARM). She is also the principal investigator for the National Science Foundation Partnerships for International Research and Education (PIRE): Bio-inspired Materials and Systems and the co-director of the Center for Research in Soft matter & Polymers (CRiSP) at the University of Delaware.

She received a B.S. in both chemistry and engineering from Clark Atlanta University as well as a B.S. in chemical engineering from the Georgia Institute of Technology in 1999. Korley completed her doctoral studies at MIT in chemical engineering and the Program in Polymer Science and Technology in 2005, and she was the recipient of the Provost's Academic Diversity Postdoctoral Fellowship at Cornell University in 2005. She was named a DuPont Young Professor in 2011 and was selected for the National Academy of Engineering Frontiers of Engineering symposium. She was a Kavli Fellow of Japanese/American Frontiers of Science Symposium from 2012-16. Recently, Korley was elected as fellow of the American Institute of Medical and Biological Engineering and was awarded the National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) Lloyd N. Ferguson Young Scientist Award for Excellence in Research. Her research focuses on bio-inspired polymeric materials, film and fiber manufacturing, plastics recycling and upcycling strategies, stimuli-responsive composites, peptide-polymer hybrids, fiber-reinforced hydrogels, and renewable materials derived from biomass.