Multiple Weak H‑Bonds Lead to Highly Sensitive, Stretchable, Self-Adhesive, and Self-Healing Ionic Sensors

• Published in: ACS applied materials & interfaces Vol. 11; no. 8; pp. 7755 - 7763
• Main Authors: Qiao, Haiyan, Qi, Pengfei, Zhang, Xiaohui, Wang, Linan, Tan, Yeqiang, Luan, Zhaohui, Xia, Yanzhi, Li, Yanhui, Sui, Kunyan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27-02-2019
• Subjects: Acrylic Resins - chemistry; Air; Animals; Biocompatible Materials - chemistry; Biocompatible Materials - toxicity; Cell Line; Cell Survival - drug effects; Compressive Strength; Humans; Hydrogels - chemistry; Hydrogels - toxicity; Hydrogen Bonding; Ions - chemistry; Rats; Water - chemistry; Wearable Electronic Devices; weak hydrogen bonds; sensitivity; ionic sensors; self-adhesiveness; self-healing
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.8b20380

Herein, we demonstrate a ternary ionic hydrogel sensor consisting of tannic acid, sodium alginate, and covalent cross-linked polyacrylamide as skin-mountable and wearable sensors. Based on the multiple weak H-bonds and synergistic effects between the three components, the as-prepared hybrid hydrogel exhibits ultrastretchability with high elasticity, good self-healing, excellent conformability, and high self-adhesiveness to diverse substrates both in air and underwater. More importantly, the ternary hydrogel exhibits high strain sensitivity especially under subtle strains with a gauge factor of 2.0, which is close to the theoretical value of the ionic hydrogel sensors; an extremely large workable range of strain (0.05–2100%); and a low operating voltage 0.07 V. Consequently, the sensor demonstrates superior sensing performance for real-time monitoring of the large and subtle human motions, including limb motions, swallowing, smiling, and wrist pulse. Therefore, it is believed that the STP hydrogel has great potential applications in health monitoring, smart wearable devices, and soft robots.