Preparation of cellulose-based three-network ionic gel and its application in human sensor

Abstract

A lignin-embedded nanocellulose (LCNC) hydrogel, derived from repurposed wheat straw biomass, was fabricated through a ZnCl₂-mediated soaking process. This innovative hydrogel leverages acrylamide/acrylic acid (AM/AA) monomers as a polymerizable deep eutectic solvent (PDES), enhancing its structural integrity. Notably, the hydrogel exhibits remarkable properties, including a minimal water loss rate of less than 5 %, a peak compressive stress of 0.28 MPa, Young's modulus of 0.015 MPa, a minimum impedance of 500 Ω, and an impressive conductivity of 8.0 × 10⁻⁴ S/m. Furthermore, when integrated into a sensor, it demonstrates a sensitivity factor (GF) of 0.08 KPa⁻¹. Selecting this advanced hydrogel as the foundation for a piezoresistive stress sensor, we investigated its capability to detect subtle bodily motions. Our findings underscore the sensor's remarkable versatility; it not only promptly registers significant arm and wrist movements but also meticulously captures delicate throat movements during swallowing, finger flexion, and even the weight distribution when gripping heavier objects. This (PAM-PAA)/LCNC/SA-Zn²⁺ hydrogel-based sensor holds immense potential for many applications, including wearable technology, smart devices, health monitoring systems, and human motion recognition platforms. Its ability to accurately track and interpret a range of bodily movements and pressures underscores its significance in advancing the field of personal health tracking and interactive technologies.