Our team develops stimuli-responsive materials and bio-hybrid materials that are designed for additive manufacturing (AM, or 3D printing) processes. The field of AM has re-emerged into the spotlight in the last 5-10 years driven by the rapid progress in the hardware (i.e., the 3D printer) and software. AM affords several benefits for low and medium volume production. Industry and national laboratories have been using AM for decades for rapid prototyping and design iteration. AM also enables personalized manufacturing, wherein the product can be customized to meet the needs or requirements of the individual—whether it is for an orthotic or an implant. Additionally, with the availability of 3D printers for the average user increasing, one can envision a day where 3D printers are as widely distributed as an inkjet printer, and will be found in homes, offices, hospitals, or even on all shuttles orbiting earth!
In contrast to the rapid progress seen for AM hardware and software, the materials currently employed with these new technologies are typically off-the-shelf products that were not necessary designed for the purpose of AM. These materials can exhibit limited processability or compatibility with AM hardware, or lack the adequate physical properties required of the printed object for its application. Thus, there is an opportunity to design and create new materials that meet the specifications to be printed using an AM process, but also afford new capabilities and functionality in the printed objects.
Our strategy to design materials for AM is to utilize macromolecular architecture and composition to control the viscosity of resins and inks. The overarching objectives of the group are:
Design and synthesize triblock copolymer hydrogels with stimuli-responsive behaviors that enable AM. The ideal ink for direct-write 3D printing is shear-thinning—the viscosity of the ink should decrease with shear rate to facilitate its extrusion from a nozzle. We develop triblock copolymers with poly(alkylene oxide) backbones that form temperature- and shear-responsive hydrogels. The long-term objective of this work is to fundamentally understand how the macromolecular architecture and composition our triblock copolymers affect the viscoelastic properties of the corresponding hydrogels. This correlation is important to understanding the 3D printability of these hydrogel inks, as well as the mechanical properties of the printed object.
Develop functional polymer gels that afford stimuli-responsive behaviors after AM. The incorporation of stimuli-responsive polymers into objects printed using AM technologies can afford complex geometrical objects that change their chemical and physical properties in response to specific environmental cues. We have developed hydrogels, nanocomposite hydrogels, and ionogels that can be 3D printed using a direct-write 3D printer to afford printed objects that exhibit stimuli-responsive behaviors. Most recently, we have been participating in a multi-PI collaboration (with the Boydston group at the University of Wisconsin, Craig group at Duke University, Boechler group at UC San Diego, and the Storti and Ganter groups at the UW) where our role has been to incorporate mechanophores into hydrogel and ionogel inks to afford 3D printed objects that exhibit a response to mechanical forces.
Biohybrid materials. AM provides the opportunity to forge new paths and identify applications and technologies that are otherwise challenging to execute or implement. We are broadly interested in printing biohybrid materials that include living materials (comprised of living cells residing within a polymeric matrix) and protein-polymer composites. These materials are applicable toward a diverse range of applications that include cell-immobilized biocatalysis, tissue engineering, and 3D printed medical devices.