POS2-0384
Controlling Initial Interfacial Adsorption to Direct Interfacial Chain Exchange Dynamics in Polymer Nanocomposites
Topic
S2. High-End Characterization/Polymer Physics/Properties
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Eunjin Choi (Seoul National University)
Co-Author(s)
Abstract
Polymer nanocomposites (PNCs) possess enhanced mechanical, thermal and electrical properties, which are strongly governed by polymer-nanoparticle interfacial interactions. During thermal annealing, physically adsorbed polymer chains can undergo desorption, adsorption, and competitive exchange, leading to continuous interfacial restructuring. While competitive adsorption has been identified as a key driving force for interfacial evolution, the influence of the initial adsorption state on subsequent interfacial chain exchange remains unclear.
Here, we investigated how the initial interfacial adsorption state affects interfacial polymer chain exchange dynamics and particle-network formation in PNCs. First, PNCs with different pre-adsorbed layers were prepared by varying the initial thermal annealing time, resulting in increased adsorbed polymer amounts, improved interparticle ordering, and higher effective NP volume fractions. Then, preferentially adsorbing low-MW polymers were introduced into pre-formed PNCs with pre-adsorbed high-MW polymers, which induce MW-dependent interfacial restructuring. Small-angle X-ray scattering and in situ rheological tests confirmed that a more developed initial adsorbed layer substantially delays low-MW induced particle-network formation. Nevertheless, after sufficient thermal annealing, all PNCs converged to an equilibrium state. Comparable activation energies for interfacial chain exchange were obtained regardless of the initial adsorption state, indicating that this kinetic delay is attributed not to a change in the fundamental energetic barrier, but to the increased number of surface contact points and adsorbed chains that must be displaced. These results revealed that the initial adsorption state governs the kinetics of interfacial chain exchange rather than the activation barrier. This study provides insight into controlling interfacial chain exchange dynamics in PNCs through systematic design of polymer-nanoparticle interfaces.
Here, we investigated how the initial interfacial adsorption state affects interfacial polymer chain exchange dynamics and particle-network formation in PNCs. First, PNCs with different pre-adsorbed layers were prepared by varying the initial thermal annealing time, resulting in increased adsorbed polymer amounts, improved interparticle ordering, and higher effective NP volume fractions. Then, preferentially adsorbing low-MW polymers were introduced into pre-formed PNCs with pre-adsorbed high-MW polymers, which induce MW-dependent interfacial restructuring. Small-angle X-ray scattering and in situ rheological tests confirmed that a more developed initial adsorbed layer substantially delays low-MW induced particle-network formation. Nevertheless, after sufficient thermal annealing, all PNCs converged to an equilibrium state. Comparable activation energies for interfacial chain exchange were obtained regardless of the initial adsorption state, indicating that this kinetic delay is attributed not to a change in the fundamental energetic barrier, but to the increased number of surface contact points and adsorbed chains that must be displaced. These results revealed that the initial adsorption state governs the kinetics of interfacial chain exchange rather than the activation barrier. This study provides insight into controlling interfacial chain exchange dynamics in PNCs through systematic design of polymer-nanoparticle interfaces.
