The underlying structural blocks of nature’s high performance materials are polypeptides, which exhibit secondary structures that contribute to the high degree of molecular ordering observed in biohybrid materials.
Our approach emphasizes the solid-state organization and performance of polyurethane/urea-peptide motifs. This new class of bio-inspired elastomeric, polymer peptide hybrids exhibit a nanostructured morphology with multiple levels of organization that have applications as responsive films/fibers, injectable hydrogels, and shape memory systems. Understanding of architecture, connectivity, and non-covalent/covalent interactions is key drivers of these systems. Recent research focuses on developing multifunctional materials derived by incorporating functional nanofillers into the bioinspired elastomers.
Graduate Student: Daseul Jang
A bilayer actuator consists of an active stimuli-responsive layer interfaced with a passive inert layer to achieve bending, like the scales of a pinecone.
Inspired by this muse, we are interested in utilizing nanocomposite structures to fabricate responsive systems through the use of embedded electrospun fibers in the active layer. We are also looking into using additive manufacturing to improve geometrical control for these structures.
Graduate Student: Francis Klincewicz
Lignin-derived thermosets and thermoplastics
Lignocellulosic biomass is the most abundant source of natural aromatics on the Earth. Depolymerization of lignocellulosic biomass can lead to several well-defined aromatic chemicals with inherent functional handles, which can be modified through post-processing.
Our group aims to develop the next generation of sustainable polymers (both thermosets and thermoplastics) using these bio-derived aromatics and investigate the fundamental understanding of structure-property relationships of these novel systems. We also strive to construct high value materials from the by-products of the synthesis to reduce waste, as well as devise efficient processing routes to open up new avenues of their applicability.
Graduate Students: Jignesh Mahajan, Maida Mahmood, Yu-Tai Wong
Sourcing polymers from biological processes, such as bacterial fermentation, is a sustainable way to provide high-quality materials that degrade after their use-life. Poly(hydroxyalkanoates), or PHAs, are one such example of a biologically-sourced material which is biocompatible and enzymatically degradable in the environment. PHAs, in addition to other biodegradable materials, can replace widely-utilized commodity polymers due to their desirable strength, toughness, and other properties, but their lifespan can be tuned strategically to avoid polluting the environment.
Graduate Student: Joanne Norris
Supramolecular Networks and Blends
Interpenetrating polymer networks (IPNs) incorporate two or more physically entangled polymer networks to offer a platform for manipulating properties within different phases. The forced compatibility of physical entanglements brings improved mechanics to the resulting networks, and the interplay between distinct chemical structures delivers tunability to material properties.
Our group focuses on the application of IPNs into both sustainable systems and supramolecular platforms to facilitate the study of phase behaviors and toughening mechanics. The enhancement of mechanical properties also inspires us to investigate the mechanisms of phase separation and energy dissipation, and development of a design strategy using elastomeric and stiff networks within the IPN framework.
Graduate Student: Yu-Tai Wong
Bio-Inspired Supramolecular Elastomers
Natural systems, such as mussel byssal threads, take advantage of reversible, non-covalent chemical interactions in order to impart energy dissipation and self-healing behaviors on materials. In our group, we aim to incorporate these supramolecular chemistries to enhance mechanical properties of elastomers, as well as explore the effects of non-covalent assembly on the structure and properties of polymer-peptide hybrid materials.
Graduate Student: Jessica Thomas
Plastics Upcycling and Recycling
Plastics play an indispensable role in every aspect of modern life. The increasing demand for lightweight and resilient materials, along with the significant environmental threats from plastics waste and pollution, particularly from single-use plastics, requires a new paradigm in end-of-life management of polymer plastic waste (PPW). Our efforts in this area involve the design of new high-performance and reprocessable materials via upcycling approaches of PPW and the development of innovative additive manufacturing strategies for post-consumer recycling and upcycling
Random Fiber Composites
Fibrous materials provide exciting opportunities as reinforcing agents. By embedding fibers in a mechanically weak matrix, such as a hydrogel, synergistic enhancement of mechanical properties (e.g. compressive stiffness and stability) can be achieved. During multilayer coextrusion or electrospinning of high surface area fiber mats, it is possible to tune mechanical and structural properties through control over relevant processing parameters. Our group works to produce functional composite materials, for example tissue engineering scaffolds, using an understanding of structure-property relationships and methods that allow for the inclusion of biologically relevant materials and therapeutics.
Postdoctoral Associate: Laura Beckett
Graduate Student: Kris van de Voorde
Multilayer coextrusion is a polymeric fiber-producing platform which can be used for the fabrication of both melt-extruded rectangular fiber mats and reinforced hydrogel composites via an in situ approach. Here, immiscible polymers are co-extruded through a series of ‘multiplier’ dies to form layered, large-scale films with layer thicknesses ranging from the nano- to micro-scale. Distinct advantages of this modular approach over other traditional fiber processing techniques include scalability, environmentally-friendly conditions, and the ability to obtain cross-sectional dimensions on the nanoscale