Oriented Ti3C2Tx MXene-doped Silk Fibroin/hyaluronic Acid Hydrogels for Sensitive Compression Strain Monitoring with a Wide Resilience Range and High Cycling Stability

Flexible strain sensors have attracted the attention of researchers due to their wide range of applications in wearable electronic skin and healthcare monitoring. The fabrication of flexible strain sensors with high strength, good linear sensitivity, stability and comfort is still challenging. Here, an anisotropic silk fibroin (SF) based hydrogel is fabricated through an oriented freezing method and a low-temperature concentration is to follow. This approach combines HA with SF to increase the hydrogel's water-holding capacity, and Ti3C2Tx MXene is doped as a conductive-sensitive component. Benefitting from the synergy of its well-designed components and the oriented internal crosslinking network structure, the hydrogel has a wide working range and a stable resistance response under 0∼80% compression strain. Especially the oriented hydrogel has ultra-high compression resilience (∼ 99%) in the orientation direction, and it is stable and durable for up to 10,000 cycles under 50% compression self-rebound. Flexible sensors made of conductive hydrogel were attached to the human body or combined with out-of-body clothing to detect human movement. Based on these findings, the prepared conductive hydrogel could be used as a wearable strain sensor material.