POS5-0359
Kinetically Arrested Interfacial Polyelectrolyte Complexes Enable Ionic Rectification in Ionoelastomer Heterojunctions
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Younghoon Kim (Ulsan National Institute of Science & Technology)
Co-Author(s)
Abstract
At interfaces between oppositely charged polyelectrolytes, ionic double layers (IDLs) emerge that are often treated as ionic counterparts of semiconductor depletion layers. Yet this analogy overlooks the molecular deformability of polymer-tethered charges. Here, we show that IDLs in soft polyelectrolyte heterojunctions undergo interfacial complexation, resulting in the formation of a kinetically arrested polyelectrolyte complex (PEC) layer. The interfacial PEC layer in ionoelastomer (IE) heterojunctions is directly visualized via selective counterion-exchange staining with ionic fluorophores, revealing a micron-scale unstained interfacial region—far exceeding the depletion length predicted from thermodynamic considerations of IDLs. This micron-scale exclusion arises from a kinetically frozen glassy interfacial PEC that suppresses counterion exchange with ionic fluorophores. Forward bias, elevated temperature, or salt addition reversibly drives a glass-to-rubber transition in the interfacial PEC that restores fluorophore uptake, leading to the disappearance of the unstained interface. This transition produces asymmetric ionic conductivity, demonstrating that ionic current rectification in IE heterojunctions is governed by interfacial PEC formation and kinetic arrest rather than by classical thermodynamic models of IDLs.
