Artemisia ciniformis-enhanced multifunctional hydrogel with ionic conductivity and anti-freezing properties for...

This study investigates the formulation of a multifunctional hydrogel for wearable sensor applications using polyvinyl alcohol (PVA), Chitosan (CS), sophorolipid (SL), and Artemisia ciniformis extract (ATC). It was characterized via FTIR, ICP, TGA, DSC, SEM, ESEM, swelling, adhesion, tensile, rheology, conductivity tests, and MTT assays. FTIR spectroscopy confirmed the presence of specific chemical functional groups and the physical structure of the hydrogel, while ICP analysis verified the presence of ions within the ATC extract. SEM results indicated that SL altered the hydrogel structure from a layered to a porous morphology, with the pore size in the swollen sample of PCAS (PVA-CS-ATC-SL) being 5.1 times larger than in the dry state. TGA and DSC studies demonstrated the hydrogel's thermal stability and antifreeze properties, remaining effective at temperatures as low as -43.3 °C. Rheological tests revealed that adding SL enhanced thixotropy and extended the linear viscoelastic range (up to 62.1 % strain), with a mechanical strength of 484.0 Pa. ATC contributed an ionic conductivity of 4.0 × 10^-2 S/m, enabling effective motion sensing. Adhesion tests (ASTM-F2255) on hen skin showed strong bonding (17.2 kPa). The biocompatible hydrogel showed >90 % cell viability (MTT) and enhanced adhesion, mechanical/electrical properties, and antifreeze performance, ideal for wearable biosensors.