Highly compressible porous polyethyleneimine/chitosan composite aerogel with excellent mechanical properties as wide detection range sensors for human motion monitoring

Abstract

Biomass three‐dimensional composite aerogels have garnered significant attention in the realm of wearable electronic skin owing to their favorable properties, including excellent human compatibility, environmentally benign degradability, and continuous porous architecture. However, conventional biomass aerogels suffer from inadequate mechanical flexibility, susceptibility to irreversible deformation under high compressive stress, and limited reusability, thereby constraining their applicability in sensing technologies. To address these limitations, this study presents the development of porous CCS/KH560/PEI/CNT‐COOH (CKPC) composite aerogels through a freeze–drying process. Chemical crosslinking was achieved using silane coupling agent (KH560) with carboxymethyl chitosan (CCS) and polyethyleneimine (PEI), while carboxylated carbon nanotubes (CNT‐COOH) were incorporated as conductive fillers. This approach successfully overcame the issues of poor mechanical properties, low elasticity, and unbalanced sensitivity‐sensing range trade‐off in chitosan‐based aerogel sensors. The results revealed that the porous CKPC aerogels exhibited a remarkable mechanical compressive strain of 86.3% while maintaining structural integrity post‐unloading. The CKPC composite aerogel‐based sensor demonstrated a high sensitivity of 42.9 within a wide strain range of 60%–76.3%, accompanied by a stable and repeatable electrical signal response across varying strains. The porous structure of the CKPC conductive aerogel sensor holds promising applications in human motion monitoring and flexible electronics.