Structure-Dependent Ion Conductivity in Poly(ionic liquid)-based Hybrid Electrolytes by Professor Pinar Akcora

NTU MSE Seminar Hosted by Professor Hu Xiao

Abstract

Dispersion and self-assembly of polymer-grafted nanoparticles have been utilized for diverse applications requiring enhanced thermo-mechanical properties, solute transport in membrane separations, or enhanced conductivity in hybrid electrolytes. The interfacial resistance to ion transport between the filler and polymer generally limits the ionic conductivity in polymer nanocomposites. We aim to overcome this limitation by designing hybrid electrolytes based on single-ion conducting polymers grafted on nanoparticles. Poly(ionic liquid)-grafted nanoparticles (PILgNPs) are building units of PIL-based hybrid electrolytes where the nanoparticle structures and the connectivity of polyelectrolyte chains determine ion transport properties. This connectivity is enhanced by increasing the molecular weight of grafted PIL chains, which further enhances their molar conductivity. Next, I will present the new poly(ionic liquid)-b-poly(methyl methacrylate) (PIL-b-PMMA) copolymer-grafted nanoparticles. Our results indicate that the copolymer hybrid design exhibits significantly higher molar conductivity than PILgNPs. The PIL block length, diblock sequence and the ionic liquid addition into copolymer morphologies change the net repulsion between nanoparticles causing pathways of different thicknesses and morphologies for ionic conduction. Further, we investigated the polarization response of PILgNPs under electric fields. By designing dielectric experiments, where the conductivity of the samples is measured under large voltage gradient, we tested how the graft density and length parameters influence the polarization of chains by electric fields. The experimental results combined with the molecular dynamics simulations suggested that the chain polarization induces graft chain orientations under electric fields. The findings help us to understand the behavior of hybrid electrolytes under electrified conditions, with direct relevance to sensors and actuators. 

Biography


Professor Pinar Akcora
Department of Chemical Engineering and Materials Science
Stevens Institute of Technology

Pinar Akcora is a professor in the Chemical Engineering and Materials Science Department at Stevens Institute of Technology in Hoboken, New Jersey, USA. She received her Ph.D. in Chemical Engineering at the University of Maryland-College Park in 2005 and completed her post-doctoral work at Columbia University between 2005-2008. She joined University of Missouri-Columbia, Chemical Engineering as an assistant professor in 2008 and has moved to Stevens in 2010. She is the recipient of the 2010 NSF-CAREER award and has received several grants from DMR, CMMI, CHE programs of NSF and ACS PRF. She served as the coordinator of the Nanotechnology Graduate Program at Stevens between 2013-2025.