The Fall 2021 MatSE 590 for graduate students consists of an exciting and jam-packed schedule. MATSE 590 is a colloquium (1-3 credits) consist of a series of individual lectures by faculty, students, or outside speakers.
Graduate students will receive a weekly email with information via @psu.edu email. Graduate students are required to attend all 590 Seminars. If you have any questions, please email Hayley Barnes at email@example.com.
*Due to the ongoing Covid Pandemic this program is being offered virtually through Zoom. Please reference the weekly email from Hayley Barnes (firstname.lastname@example.org) for Zoom link.
December 9, 2021
"Coarse-grained modeling of ion transport through block copolymers"
Lisa Hall, Ph.D. Associate Professor of Chemical and Biomolecular Engineering, The Ohio State University
Microphase separating copolymers are attractive for transport applications because one microphase can solvate and allow transport of ions or small molecule penetrants, while another provides mechanical strength or other desired properties. However, the relatively low ion conductivity through such materials remains a challenge; strategies to improve cation conduction for applications such as battery electrolytes include using larger anions or a higher dielectric strength polymer (which more strongly solvates ions). These strategies effectively decrease the strength of ion-ion interactions and thus can reduce ion agglomeration and correlated cation/anion motion. However, strong ion-polymer interactions also slow ion motion, and when the polymer more strongly solvates smaller cations versus larger anions, this can lower the transference number (fraction of the conductivity contributed by the cation). We study these competing effects using coarse-grained molecular dynamics (MD) simulations which include a 1/r4 potential to capture size-dependent ion-monomer and ion-ion solvation effects. This is the same form as the interaction between an ion and an induced dipole and allows us to capture the experimentally observed trends in lamellar domain spacing and ion conductivity versus ion concentration. The impacts of ion size and polymer dielectric strength on ion correlations, diffusion, and cation conductivity in salt-doped homopolymer and block copolymer systems, along with initial results on single ion conducting systems, will be discussed.
Lisa Hall is an Associate Professor at the Ohio State University. She joined OSU in 2012, having completed her Ph.D. with Kenneth Schweizer at the University of Illinois and a subsequent postdoctoral appointment with Amalie Frischknecht and Mark Stevens at Sandia National Laboratories. Her research group uses statistical mechanical theory and molecular dynamics simulations to study molecular behavior and properties of nanostructured polymeric materials. She received a CAREER award from the National Science Foundation in 2015, focused on efficiently modeling ion conduction in block copolymer electrolytes. She also recently was selected for the Owens Corning Early Career Award from the Materials Engineering & Sciences Division of the American Institute of Chemical Engineers.