Highly Strong, Tough, and Stretchable Conductive Hydrogels Based on Silk Sericin-Mediated Multiple Physical Interactions for Flexible Sensors

作者：Feifei Wang, Zhen Li, Jianqiang Guo, Lin Liu, Hao Fu, Juming Yao, Izabella Krucińska, Zbigniew Draczyński · 发表于：ACS Applied Polymer Materials · 年份：2021 · DOI：10.1021/acsapm.1c01553 · 被引用次数：57 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Silk-based biomaterials and applications、Conducting polymers and applications

The development of hydrogel-based electronic sensors integrated with excellent mechanical performance, conductivity, high sensitivity, and stability is still a great challenge. In this work, a highly strong, tough, and stretchable conductive hydrogel was proposed using silk sericin (SS), polyvinyl alcohol (PVA), and sodium citrate (Na 3 Cit) via combining freeze–thaw with the salting-out route. SS with rich-binding sites (−COO –, −NH 2, and −OH) was exploited to construct an ionic conductive hydrogel with multiple physical interactions containing hydrogen bonds, ionic coordinations, and hydrophobic interactions. The obtained composite hydrogels (PVA/SS/Na 3 Cit) displayed a prominent tensile strength of 4.42 ± 0.32 MPa, an elastic modulus of 3.14 ± 0.26 MPa, a toughness of 13.73 ± 1.05 MJ/m 3, and an excellent stretchability (>500% of strain) and self-recovery. In addition, the introduction of SS not only mediated the noncovalent cross-link network but also enabled excellent ionic conductivity of the hydrogels due to the coordination effect of Na + and Cit 3– ions. Moreover, the PVA/SS/Na 3 Cit conductive hydrogels can be used as a strain sensor to monitor human activities, and they exhibit a wide work range, good sensitivity, and stability, suggesting promising applications in flexible and stretchable wearable electronics.