Silicon-Enhanced PVA Hydrogels in Flexible Sensors: Mechanism, Applications, and Recycling.

Hydrogels, known for their outstanding water absorption, flexibility, and biocompatibility, have been widely utilized in various fields. Nevertheless, their application is still limited by their relatively low mechanical performance. This study has successfully developed a dual-network hydrogel with exceptional mechanical properties by embedding amino-functionalized polysiloxane (APSi) networks into a polyvinyl alcohol (PVA) matrix. This hydrogel effectively dissipates energy through dense sacrificial bonds between the networks, allowing for precise control over its tensile strength (ranging from 0.07 to 1.46 MPa) and toughness (from 0.06 to 2.17 MJ/m) by adjusting the degree of crosslinking in the polysiloxane network. Additionally, the hydrogel exhibits excellent conductivity (10.97 S/cm) and strain sensitivity (GF = 1.43), indicating its potential for use in wearable strain sensors. Moreover, at the end of its life (EOL), the sensor waste can be repurposed as an adsorbent material for metal ions in water treatment, achieving the recycling of hydrogel materials and maximizing resource utilization.