A collaborative study led by researchers at Michigan State University, Oak Ridge National Laboratory, National Institute of Standards and Technology, and Argonne National Laboratory has unraveled the molecular origin of the high mechanical strength enhancement of polymer nanocomposites.
Shiwang Cheng, an assistant professor of chemical engineering and materials science in the MSU College of Engineering, said the research clarified a half-century-old puzzle on the explicit role that nanoparticles play on the enhancement of polymer nanocomposites.
Details of the new study have been published in the journal Physical Review Letters and highlighted as an Editors' Suggestion. Ruikun Sun, a graduate student of chemical engineering and materials science, is the first author of the article. According to Physical Review Letters, only one in six accepted letters is highlighted as an Editors' Suggestion.
"Polymer nanocomposites are important lightweight materials for numerous applications," Cheng explained. "They keep our vehicles light and increase fuel efficiency. They make our homes and buildings energy efficient and are playing more and more important roles in healthcare and medication."
Cheng said all these attractive applications can be directly or indirectly attributed to the nano-reinforcement effect of nanoparticles. The lack of molecular understanding of this effect imposes a grand challenge on advancing the design and manufacturing of polymer nanocomposites, he continued.
"Our findings clarify a long-standing puzzle regarding the molecular origin of the mechanical reinforcement mechanism in deformed polymer nanocomposites. It challenges the prevailing viewpoint of molecular overstraining as the major mechanism for the mechanical enhancement of polymer nanocomposites. It also provides a new perspective for understanding the hydrodynamic effect of nano-sized particles in a viscoelastic medium," he added.
Cheng's Soft Materials research group at MSU focuses on understanding the processing-structure-property relationship of multicomponent polymeric materials for advanced materials design and processing, including polymer nanocomposites, associating polymers, and solid polymer electrolytes. In 2018, Cheng received international recognition when he was awarded the Peter Debye Prize for Young Investigators for "significant results on polymer nanocomposites."
This work was mainly supported by Ralph E. Powe Junior Faculty Enhancement Awards from Oak Ridge Associated Universities from Cheng's group and DOE Early Career Award (KC0402010) from collaborator's group (Yangyang Wang). Access to small-angle neutron scattering and small-angle x-ray scattering was supported by NIST and NSF under agreement No.DMR-1508249 and ANL under contract No. DE-AC02-06CH11357.