Enhanced Mechanical Properties of PVA-Based Multifunctional Conductive Hydrogel Sensors with Cyclodextrin Slide-Ring as a Crosslinker
Abstract
Developing hydrogels that simultaneously combine high mechanical robustness, antifreezing capability, and stable conductivity remains a substantial challenge for flexible sensing materials. Herein, we report a multifunctional conductive rotaxane-crosslinked hydrogel constructed from a γ-cyclodextrin/poly(ethylene glycol) diacrylate (γ-CD/PEGDA) slide-ring crosslinker embedded in a poly(vinyl alcohol) (PVA)/acrylamide (AM)/xanthan gum (XG)/Zn2+ network. The threaded crosslinker introduces movable junctions into the network, allowing stress redistribution through a pulley effect and thereby improving the mechanical performance of the hydrogel. Together with hydrogen bonding, Zn2+ coordination, and the physically crosslinked PVA network, this design generates a robust multicomponent architecture. The optimized hydrogel exhibited a tensile stress of 3.2 MPa, an elongation at break of 254%, and a toughness of 40 MJ m−3, together with high puncture resistance and cyclic stability. The hydrogel also showed a freezing point of −20.59 °C and a low equilibrium swelling ratio in water, indicating favorable antifreezing and antiswelling performance. Owing to interconnected ionic conduction pathways, the material further displayed stable ionic conductivity and reliable strain-sensing behavior over a broad strain range, with rapid response/recovery and effective monitoring of human motion and subtle physiological activities. This work provides a practical strategy for constructing mechanically robust, antifreezing, and conductive hydrogels for wearable sensing and related bioelectronic applications.