Multiscale ion transport channels based on chitosan and nanocellulose: Synergistic enhancement of mechanical properties and ionic conductivity, and multifunctional integration.

Abstract

Eutectogels are promising in flexible wearable electronics, but the inherent trade-off between mechanical strength and ionic conductivity limits their development. Here, we introduced polyethyleneimine-modified cellulose nanocrystals (PEI@CNC) and chitosan (CS) into a polyvinyl alcohol (PVA) matrix, and constructed a PVA composite eutectogel (PCxSy) with an aligned lamellar porous structure via directional freezing. The anisotropic low-tortuosity channels, combined with the incorporation of PEI@CNC and CS that provide additional ion-conducting pathways, endow the material with an ionic conductivity of 0.74 S·m-1. Meanwhile, multiple hydrogen bonds among PVA, CS, PEI@CNC, and the DES components form a dense physical network, providing excellent mechanical properties along the orientation direction, with a tensile strength of 3.60 MPa and toughness of 10.39 MJ·m-3. The eutectogel exhibits dual-mode strain/pressure sensing with favorable cycling stability under bending, shearing, and compression. Zn2+ from the DES synergizes with PEI@CNC and CS to impart antibacterial activity (95.71% against E. coli, 95.44% against S. aureus), effectively reducing skin infection risk during long-term wear.