Title:

Multiscale modeling of responsive polymer networks: focus on photo-controlled degradation and pattern restructuring

Speaker:

Prof. Olga Kuksenok

Affiliation:

Clemson University

When:

Friday, November 1, 2024 at 11:00:00 AM   Add to Calendar

Where:

MRDC Building, Room 4211

Host:

Alexander Alexeev
alexander.alexeev@me.gatech.edu
4043853659

Abstract

Understanding and controlling degradation of polymer networks is critical for a broad range of applications. Degradation that can be controlled by external stimuli, for example photo-controlled degradation, permits spatially-resolved dynamic control of material properties. In the first part of my talk, I will introduce our recently developed mesoscale approach that captures degradation and erosion of polymer networks on the mesoscale. We focus on hydrogels formed by the end-linking of multi-arm polyethylene glycol precursors. We track the degradation via measuring the fraction of degradable bonds intact and spatial distributions of network fragments. Peak in reduced weight average degree of polymerization allows us to identify the reverse gel point. Our results allow one to predict mechanical properties of degrading networks. In the second part of my talk, I will focus on dynamic control of pattern formation and restructuring in hydrogels with host-guest interactions. Pattern formation under external stresses plays an important role in defining functionality of a broad range of soft confined systems. We recently developed continuum-level model to capture the dynamics of PNIPAAm hydrogels with pendant azobenzene moieties immersed into alpha-cyclodextrins (alpha-CD) solutions. While trans-azobenzene moieties are recognized and accommodated by the alpha-CD cavities to form inclusion complexes, an exposure to UV light drives the trans-to-cis photoisomerization and dissociation of the complexes. We use spaciotemporal variations in UV irradiation to control pattern formation in hydrogel films under the rigid and soft confinements and to control hysteresis loops. The above examples of modeling stimuli-responsive networks could provide guidelines for future design of materials with dynamically controlled properties and functionalities.

Biography

Dr. Kuksenok is an Associate Professor at the Materials Science and Engineering Department at Clemson University in Clemson, SC. Dr. Kuksenok received her Ph.D. in Physics and Mathematics from the Institute of Physics, National Academy of Sciences of Ukraine, Kiev, Ukraine. Dr. Kuksenok’s research interests and accomplishments span the following areas of computational materials science: elastodynamics of responsive polymer gels, dynamics of multi-component polymer blends, biomimetic materials, pattern formation in non-equilibrium systems, and theory of heterogeneous liquid crystals. Prof. Kuksenok has authored over 100 journal publications and 10 book chapters. Currently she is co-editing a book “Handbook of coarse-grained and multiscale modeling of soft matter: from the fundamentals to scientific and industrial applications”. She served as an editorial board member of PLOS ONE Polymer Chemistry and is currently serving as an Editorial Board Member of Communications Physics (Nature Portfolio).