Colloquium Series: Dr. Joseph Tracy, NC State University
Tuesday, October 29 @ 4:00 pm - 5:00 pm
Dr. Joseph Tracy
Professor of Material Science and Engineering
NC State University
Tuesday October 29, 2024, 4pm Chapman Hall Rm. 125
Title: Magnetically and Optically Active Nanoparticles and Polymer Composites
Abstract:
Magnetic fields and light are appealing for assembling, manipulating, and heating magnetic microparticles and plasmonic nanoparticles (NPs). Simple soft actuators will be presented, where embedded magnetic microparticles and plasmonic NPs render them responsive to magnetic fields and light. Photothermal triggering of Au nanorods (GNRs) in shape memory polymers and 3D-printed, thermoresponsive hydrogels drives shape morphing. Combining magnetic actuation and photothermal heating enables remote configuration, locking, unlocking, and reconfiguration of soft actuators. Use of hard-magnetic NdFeB microparticles makes possible controlled remagnetization to reprogram soft actuators for new tasks. Composite and multifunctional NPs are of interest for coupled properties that enhance their capabilities. For example, cationic Fe3O4 NPs undergo electrostatic self-assembly on the surface of anionic GNRs, yielding MagGNRs, which align in magnetic fields and have polarization-dependent extinction. Furthermore, pH is a useful lever for controlling the assembly and disassembly of MagGNRs. These materials are promising for applications in soft and nano- robotics, medical devices, imaging, and sensing.
Bio:
Joseph Tracy is a Professor in the Department of Materials Science and Engineering at North Carolina State University. He completed his undergraduate studies in Chemistry at the University of California, Santa Barbara in 2000. After receiving his Ph.D. in Physical Chemistry from MIT in 2005, he conducted postdoctoral research at the University of North Carolina, Chapel Hill and joined NC State in 2007. His research focuses on the synthesis, characterization, self-assembly, and applications of noble metal and magnetic nanoparticles, with a special interest in responsive polymer composites. He is a NC State University Faculty Scholar, Humboldt Research Fellow, Fellow of the Royal Society of Chemistry and recipient of NSF CAREER and Alcoa Foundation Engineering Research Achievement Awards.