Speaker: Nayomi Plaza, Materials Research Engineer, USDA Forest Service, USA

Abstract: Wood is a complex hygroscopic material with multiple levels of structure that influence its properties and ultimately, performance.  Yet, our understanding of the relationship between wood nanostructure and its macroscale performance is limited and hinders the development of new technologies that can fully unlock wood’s potential as a material. Neutrons are particularly suited to probe these length scales. Contrast can be enhanced using deuterium and we can study the changes in wood nanostructure due to chemical infiltration, fungal decay exposure or moisture-uptake using custom-built humidity chambers. Techniques we have utilized to study wood include small angle neutron scattering, quasielastic neutron spectroscopy, neutron spin echo, and even spin echo small angle neutron scattering.

This seminar will focus on our sample preparation strategies for studying wood with neutrons. We use custom-built razor blade guillotines or sliding microtomes to make less than 1mm thick samples. Samples must often be held flat, particularly, in humidity-controlled experiments where thin specimens might curl. Lessons learned on how to minimize artifacts arising from sample preparation will be highlighted.

Biography: Since 2018 Nayomi Plaza has been a Materials Research Engineer in the Forest Biopolymer Science and Engineering group at the USDA Forest Service, Forest Products Laboratory in Madison, WI, USA. She received a BS in Mechanical Engineering in 2011 from the University of Puerto Rico- Mayagüez. Soon after she moved to WI to pursue a PhD in Materials Science at the University of Wisconsin-Madison (UW-Madison). In 2012 she was recognized as an NSF Graduate Research Fellow, and in 2015 she received a DOE Office of Science Fellowship to spend a year at the Oak Ridge National Laboratory to complete her thesis research. In 2017 she completed her PhD, focused on neutron scattering studies of wood-water nanoscale interactions, and joined the Forest Products Laboratory as a scientist.  Nayomi also serves as an honorary adjunct professor in the UPR-Mayagüez Materials Science & Engineering Program, and a Research Associate at the UW-Madison Chemical & Biological Engineering Department. Her current research interests include development of scattering-based techniques using x-rays, light, and neutrons to study nanostructure of wood, cellulose nanomaterials, bio-based adhesives and other forest products in conditions that mimic their use and/or operation. She is particularly interested in understanding the role of wood nanostructure in its macro-scale properties. Her work has been recognized through invited talks and awards including the 2018 Forest Products Society Wood Award, and 2022 Most Promising Early Career Research Scientist by HENAAC.