Boosting Electronic Charge Transport in Conductive Hydrogels via Rapid Ion-Electron Transduction

Traditional design of conductive hydrogels involves embedding conductive components within a hydrated polymeric network to establish interconnected electron pathways. While the hydration shell of the polymeric network is typically considered insulating, we demonstrate that it can enhance electron transport. Using a PEDOT:PSS hydrogel, we propose a hierarchical network with an inhomogeneous topological structure, consisting of entangled PSS chains, dense PSS assemblies, and PEDOT microcrystals. In the hydrated state, the dense PSS assemblies significantly lower the energy barrier for electron hopping between PEDOT microcrystals, thereby promoting electron transport. As a result, the charge transport mechanism in these hydrogels is predominantly electronic rather than ionic, effectively mimicking the behavior of electronic conductors. The charge transport rate reaches up to 2 × 10⁶ m s^-1, which is approximately five orders of magnitude higher than that of ion-based processes. This characteristic imparts the hydrogels with kinetically sensitive ion-electron transduction, enabling time-resolved electrochemical analysis of biochemical processes.