Hybrid strengthening of cellulose nanocrystal-based solvent co-cross linked flexible organohydrogels with fast self-healing, diverse adhesive nature, and anti-freezing behavior for advanced human health monitoring

Abstract

Continuous real-time monitoring of non-cognitive markers is essential for the preliminary detection, control, and regulation of long-standing health conditions. Existing diagnostic techniques are frequently invasive and often not well suited for at-home monitoring, limiting their use in early detection of disorders. In this study, a flexible organohydrogel-based wearable sensor has been developed offering high accuracy and durability for real-time human health assessment. Employing a solvent co-cross linking strategy, a wrinkle texture organohydrogel is synthesized by combining polyacrylamide (PAm), and polymethylmethacrylate (PMMA) grafted onto the surface of cellulose nanocrystals (CNCs) through the free radical graft copolymerization technique. This innovative approach combines both physical and chemical interaction to eliminate mechano-chemical conflict and provide the organohydrogel with a balanced mechanical performance (2100% stretchability), toughness (519 kJ m⁻³), flexibility, conductivity ( 0.29 S m⁻¹), remarkable adhesion, wide working range (−60 °C to 60 °C), and fast self-healing properties. In contrast to conventional hydrogels, this one-pot synthesis eliminates the need for metallic nanofillers, lowering cytotoxicity. In addition, PAm in combination with CNCs also provides biocompatibility, whereas sodium chloride makes the organohydrogel ionically conductive and sensitive. The engineered sensor exhibits enhanced efficiency, durability, and sensitivity and can be employed in haptic sensing technology.