MSE Seminar: “Viscoelastic Bandgap and Thermal Transport in Inorganic-Organic Nanolaminates”

Details

Pawel Kablinski, Ph.D.

Department Head, Department of Materials Science and Engineering
Rensselaer Polytechnic University

Dr. Pawel Keblinksi received an MS degree in Physics from Warsaw University in 1990 and a Ph.D. degree in Physics from Pennsylvania State University in 1995. After postdoctoral appointments at Argonne National Laboratory and Forschungszentrum Karlsruhe, Germany he joined the faculty of the Materials Science & Engineering Department at Rensselaer Polytechnic Institute, Troy NY. He currently serves as the Department Head.

His research relies mainly on the use of classical molecular dynamics simulations to study structure-property relationships in interfacial materials, with a focus on thermal transport modeling. His work to date resulted in over 200 publications in peer-reviewed journals and associated H-index that exceeds his age. He is a recipient of a National Science Foundation Career Award (USA), Humboldt Fellowship (Germany), and Marie Curie Fellowship (EU Commission/Poland). He is also a Fellow of the American Physical Society and Materials Research Society and an Associated Editor of the Journal of Applied Physics.

Abstract

Incorporating molecular nanolayers (MNLs) at inorganic interfaces offers promise for reaping unusual enhancements in fracture energy, thermal and electrical transport.

Here, using molecular dynamics simulations we reveal that multilayering MNL-bonded inorganic interfaces can result in viscoelastic damping bandgaps. The analyses of interfacial vibrations indicate that the viscoelastic bandgap is an interface effect that cannot be explained by weighted averages of bulk responses. These findings prognosticate a variety of possibilities for accessing and tuning novel dynamic mechanical responses in materials systems and devices with significant inorganic-organic interface fractions.
 
We also characterize thermal transport in these nanolaminates focusing on transport tunability by the interfacial bonding. By comparing thermal conductivity of the nanolaminates with interfacial thermal conductance of corresponding individual interfaces, we concluded that thermal transport in these nanolaminates can be largely understood in terms of independent interfacial resistors connected in series. This is different from behavior observed in classic Si-Ge superlattices that exhibit signatures of coherent phonon transport across multiple interfaces.  Furthermore, we observe the structural change in the organic phase above 350 K leads to a significant decrease in both thermal conductivity and thermal conductance. This suggests paths towards development of interfacial structures with bonding and temperature-tunable thermal conductivity.