POS7-0611
Suppression of Initial Solvent-Driven Nonequilibrium Effect on Polymer Nanocomposites with Physically Adsorbed Bimodal Polymers
Topic
S7. Innovations in Polymeric Composites: From Design and Processing to Industrial Applications
When and Where
Oct 1, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Jinkee HONG
Ki Su KIM
Presenter(s)
Seong Min Jo (Seoul National University)
Co-Author(s)
Abstract
In polymer nanocomposites (PNCs), the interfacial polymers adsorbed onto nanoparticle surfaces play a crucial role in determining the physical properties of PNCs. Many studies have altered the intrinsic parameters such as size/shape/chemistry of particles/polymer to control adsorbed polymers. The investigation of these parameters assumed that PNCs are in equilibrium states. However, recent studies have shown that the final states of PNCs can be path-dependent, arising from the long relaxation time of polymers being in nonequilibrium, especially at the interface.
In this work, we investigate how the initial solvent-driven nonequilibrium effect on PNCs can change when the conformation of adsorbed polymers is intentionally modified. To tune chain conformation, we employ bimodal molecular weight PNCs composed of silica nanoparticles and poly(ethylene glycol) (PEG) with two different molecular weights. In this silica/PEG system, PEG end groups interact more strongly with the silica surface than the polymer backbone, allowing short chains with a higher end-group fraction to preferentially adsorb onto the particle surface. The short-chain-rich interface then mediates long-chain adsorption, producing sufficiently stretched adsorbed-polymer conformations across different solvent conditions. By correlating particle microstructure, macroscopic properties, and the formation of adsorbed layers in PNCs, we found that bimodal PNCs are less sensitive to the initial solvent pathway than unimodal PNCs. This reduced sensitivity in bimodal suppresses the solvent-driven nonequilibrium effect. These results indicate that molecular weight distribution can regulate pathway-dependent behavior by controlling the hierarchy of polymer adsorption and interfacial chain conformation. This study offers insight into how specific polymer–particle interactions and chain-length dispersity can be used to tune the nonequilibrium behavior and physical properties of PNCs.
In this work, we investigate how the initial solvent-driven nonequilibrium effect on PNCs can change when the conformation of adsorbed polymers is intentionally modified. To tune chain conformation, we employ bimodal molecular weight PNCs composed of silica nanoparticles and poly(ethylene glycol) (PEG) with two different molecular weights. In this silica/PEG system, PEG end groups interact more strongly with the silica surface than the polymer backbone, allowing short chains with a higher end-group fraction to preferentially adsorb onto the particle surface. The short-chain-rich interface then mediates long-chain adsorption, producing sufficiently stretched adsorbed-polymer conformations across different solvent conditions. By correlating particle microstructure, macroscopic properties, and the formation of adsorbed layers in PNCs, we found that bimodal PNCs are less sensitive to the initial solvent pathway than unimodal PNCs. This reduced sensitivity in bimodal suppresses the solvent-driven nonequilibrium effect. These results indicate that molecular weight distribution can regulate pathway-dependent behavior by controlling the hierarchy of polymer adsorption and interfacial chain conformation. This study offers insight into how specific polymer–particle interactions and chain-length dispersity can be used to tune the nonequilibrium behavior and physical properties of PNCs.
