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2.18.16 Zavada

Title: “Oxygen-Mediated Polymerization for Rapid Puncture-Initiated Autonomous Healing and In Situ Hydrogel Formation”

Date: Thursday, February 18, 2016

Time: 10:00 am – 11:00 am

Room: 137, NIA

Speaker: Scott Zavada

Abstract: A broad array of commercial, industrial, and medical applications rely upon the in situ formation of a solid polymeric material. The development of methods for forming solid network polymers from liquid monomers through exposure to an environmentally-borne initiation stimulus (e.g., a ubiquitous reactive compound, such as water or oxygen) holds potential for advancing the state-of-the-art technology in many applications, including the construction of autonomously-healing materials suitable for utilization in space exploration habitats and in the development of next generation medical adhesives.

As a demonstration of oxygen-mediated polymerization’s utility in autonomously healing materials, trilayered panels were fabricated by sandwiching reactive liquid monomer formulations between solid polymer sheets and punctured with high velocity projectiles; as the reactive liquid layer flows into the entrance hole, contact with atmospheric oxygen initiates polymerization, converting the liquid into a solid plug. While other self-healing approaches have utilized similar liquid-to-solid transitions, this approach permits the development of materials capable of sealing a breach within seconds, far faster than previously described methods.

The in situ formation of hydrogels is utilized in numerous biomedical applications, notably for surgical adhesives and sealants.  Unfortunately, the deleterious attributes of current materials and methods, with serious concerns over their poor physical properties and in vivo cytotoxicity, requires the development of new methods for generating biocompatible hydrogels in situ.  By utilizing oxidoreductase chemistry to effect oxygen-mediated polymerization of thiol–ene monomer formulations, hydrogels may be rapidly-generated after exposure of aqueous monomer formulations to atmospheric oxygen. The incredible versatility of thiol–ene chemistry permits the development of biocompatible materials with a broad range of properties.

 

Bio: Scott Zavada is a PhD candidate in the Macromolecular Science and Engineering program at the University of Michigan (UMich), Ann Arbor, working under the guidance of Prof. Timothy F. Scott.  In 2012, he was selected as a NASA Space Technology Research Fellow (NSTRF) and he is now in the fourth year of the NSTRF program. His mentor and collaborator in the NSTRF program is Dr. Keith Gordon from the NASA Langley Research Center (LaRC).  Prior to starting his PhD studies at UMich, Scott received his B.S. in chemistry from Adrian College (Adrian, Michigan), his M.S. in polymer technology from Eastern Michigan University (Ypsilanti, Michigan) and worked as a researcher at Precision Coatings, Inc. (Walled Lake, Michigan).  His primary research interests are in self-healing and stimuli-responsive materials.

Scott has two issued patents, given two oral presentations at American Chemical Society (ACS) national meetings, and has published three journal articles.  His recent article in ACS Macro Letters (Zavada, S. R.; McHardy, N. R.; Gordon, K. L.; Scott, T. F., Rapid, Puncture-Initiated Healing via Oxygen-Mediated Polymerization. ACS Macro Lett. 2015, 4 (8), 819-824) was selected as an ACS Editors’ Choice article and was featured in an ACS press release.  Subsequently, there was overwhelming interest from the popular media regarding this research, with articles appearing in The Economist, slate.com, Cosmos Magazine, Huffington Post, IFL Science, and New Scientist, was also featured on the Scientific American Sixty-second Science Podcast, and a video describing the research is the most viewed on the ACS Youtube channel with over 900,000 views.  Furthermore, Scott was interviewed on Michigan Radio for the Stateside with Cynthia Canty radio program.

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