Sustainable Conductive Organohydrogel Strengthened by Lignin@Polypyrrole Core–Shell Nanoparticles for Multifunctional Wearable Electronics

Abstract

Conductive gels are utilized as wearable sensors in flexible electronic materials due to their human skin-like adaptability. However, achieving high strength, durability, and sustainability simultaneously remains a challenge. In this study, a tough, durable, recyclable, green, and multifunctional semi-interpenetrating network organohydrogel was developed and enhanced by lignin@polypyrrole core–shell nanoparticles (LP9). The semi-interpenetrating network organohydrogel was constructed using environmentally friendly poly (vinyl alcohol) and bio-based gelatin. The LP9 was synthesized via in-situ polymerization of pyrrole on lignin nanoparticles, serving as rigid anchors to enhance the gel's properties and eliminate heterogeneity through hydrogen bonding. With 5% of LP9, the organohydrogel (5LP9) demonstrated a tensile strength of 2.5 MPa, elongation of 700%, conductivity of 432 mS/m, and a gauge factor of 1.7 with a good linearity, highlighting its excellent performance as an electronic conductive material. In addition, the organohydrogel exhibited remarkable environmental stability, antimicrobial properties, recyclability, and biocompatibility. When applied to human motion detection, voice recognition, and gesture recognition, the organohydrogel showcased excellent recognition ability, responsive functionality, and long-term monitoring stability. These findings provide a theoretical foundation for developing green and programmable wearable sensors for human–machine interaction, incorporating deep learning such as letter-writing recognition.

Keywords

core–shell nanoparticles / flexible strain sensor / human–machine interaction / lignin / organohydrogel / polypyrrole

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