3D printable, super compressible, antibacterial and environmentally stable dual networked ionogels as wearable pressure sensors for wireless early warning of precise health

Abstract

Piezoresistive sensors that are highly compressible, antibacterial, environmentally stable, and flexible, with exceptional sensing capabilities, are becoming increasingly popular in the field of practical wearable electronics. Yet, achieving their optimal performance simultaneously remains a considerable challenge. Herein, a typical strategy involving an ion-molecular engineering concept, along with the combination of covalent crosslinking and dynamic non-covalent interactions is employed for the fabrication of the ionogel composed of carboxylated cellulose nanofiber (CNF-P), 2-hydroxyethylacrylamide (HEAA), and zinc chloride (ZnCl₂) within the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl)–water system. The optimized iongel demonstrates 3D printing capability, exceptional stretchability and compressibility, antibacterial properties, high conductivity, and wide temperature tolerance. Furthermore, the ionogel pressure sensor exhibits a broad detection range of 0.45 Pa–2.0 MPa, an ultralow detection limit of 0.45 Pa, rapid response and recovery times of 60 ms and 59.7 ms, high sensitivity of 5.0 kPa⁻¹, and mechanical durability for 1000 cycles. Benefiting from these advantages, the ionogel pressure sensor can not only monitor human motions and physiological activities, ranging from running to pulsing, but also facilitate Morse-code-based wireless communication for advanced health monitoring and human–machine interface applications. Moreover, a 3 × 3 pressure sensor array was implemented to confirm the spatial pressure distribution. This study presents a significant advancement in pressure sensor technology for personalized health monitoring and intelligent human–machine interaction, paving the way for new applications in soft electronics and intelligent sensing.