PVA/chitosan-based multifunctional hydrogels constructed through multi-bonding synergies and their application in flexible sensors

Hydrogels have garnered significant interest as promising materials for flexible wearable devices. However, it remains a major challenge to develop multifunctional hydrogels. In this study, we prepared a multifunctional hydrogel based on the polyvinyl alcohol (PVA) and chitosan (CS), which is characterized by high strength, good electrical conductivity, and resistance to freezing and water retention. The hydrogel formulation utilizes p-carboxyphenylboronic acid (PBA) and MXene in combination with freeze-thaw cycling and glycerin (GL) immersion technology. Additionally, we explored the applications of this hydrogel in motion detection and sensing. Research results indicate that the hydrogel has excellent mechanical properties, achieving a strength of up to 3.42 MPa, with modulus and toughness improved by 7 times and 5 times, respectively, compared to pure PVA hydrogels. Moreover, when the MXene dispersion is at 8 vol%, the conductivity is 163.15 mS/m, and we explore their applications in strain sensing (GF = 7.03) and motion detection. The hydrogels exhibit a good strain range (600 %) and a fast response time (42 ms), as well as regular and stable electrical signals demonstrated at joints and breathing, providing strategic support for the application of this hydrogel in the field of smart wearable flexibility.