RUI: Optical studies of pseudoelastic nanoparticle deformation

Trinity College, Hartford CT

Investigators

Abstract

Non-Technical Abstract Nanoscience is the study of the unique properties that arise as you decrease the size of materials to less than a thousandth of the width of a human hair. Among the many exciting new phenomena and applications that have come out of such studies, one of particular interest is that nanoscale materials show vastly different mechanical properties than their bulk counterparts. For example, metal nanoparticles can deform much further and recover from much larger strains than a large piece of the same metal. This project studies that property, called pseudoelasticity, in order to understand its origins, mechanisms and limitations. The researchers, including the PI and team of undergraduate students, are using a new, non-invasive approach to measure how the mechanical properties of gold nanoparticles change with their size. This understanding will enable the design of materials with exciting new mechanical properties like unusually high strength, the ability to heal themselves, or the ability to report if they are damaged. In addition, this research introduces undergraduate student-scholars, on the research team and in the PI’s classroom, to cutting-edge topics in nanotechnology. The PI is also translating the research into educational materials to introduce students from middle school through college to the importance of physics and chemistry for the design of new technologies. Technical Abstract Metallic nanoparticles and nanostructured metals are increasingly important in modern electronic, structural and biomedical materials. An in-depth understanding of the mechanical performance of nanostructured metals is needed in order to both predict the behavior of devices currently in use as well as to design ever-improved applications. This project investigates the thermodynamics and kinetics of deformation in metal nanoparticles in order to better understand the unique mechanical phenomena that occur at the nanoscale. In particular, the researchers are taking advantage of new approaches to mechanical characterization of metal nanoparticles in order to study pseudoelasticity, a unique nanoscale phenomenon in which metal nanoparticles can recover from very large mechanical deformation. Through all-optical measurements, the research team is examining the size dependence of this intriguing behavior in order to determine the mechanism of deformation and shape recovery in small metal nanoparticles. The research is carried out at a primarily undergraduate institution, and as such is also introducing the team of undergraduate researchers to cutting-edge research topics and techniques in nanotechnology. The research team is also actively involved in developing course materials and outreach activities based on the research in order to introduce a broader audience of students, from middle school through to college, to the importance of fundamental physical and chemical phenomena in the design of new technologies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.