Wearable Flexible Sensors for Human Motion Detection\nwith Self-Healing, Tough Guar Gum-Hydrogels of GO-P4VPBA/PDA Janus\nNanosheets

Abstract

Flexible\nand wearable sensors based on nanocomposite hydrogels\nhave been used to monitor human physiological signals. However, it\nis still a challenge to develop flexible sensors using self-healing\nhydrogels with the properties of biocompatibility and flexibility.\nIn this manuscript, Janus nanosheets were implanted into guar gum\n(GG)/poly­(vinyl alcohol) (PVA) 3-dimensional network structure. The\nobtained flexible sensor with nanocomposite hydrogels had outstanding\nflexibility, high sensitivity, and excellent durability. In typical\noil-in-water (O/W) Pickering emulsion, GO-poly­(4-vinylphenylboronic\nacid)/polydopamine Janus nanosheets (JNs) were surface-initiated with\n4-vinylphenylboronic acid (4VPBA) on the side of GO by RAFT polymerization\nand self-polymeriztion of dopamine (DA) on the other side by mussel-inspired\nchemistry, respectively. The JNs hydrogels had the preferable mechanical\nstrength (1.0 MPa) and self-healing efficiency (93.1%) in the presence\nof reversible interaction. The resistive-type hydrogels sensor with\nthese JNs hydrogels exhibited high sensitivity (gauge factor (GF)\n= 12.5) and antifatigue sensing performance (100% strain, 600 cycles).\nThe sensor could monitor different human movements, which includes\nboth large-scale (wrist bending, elbow bending, and running) and small-scale\n(cough vibrations, pulse rates, and finger bending) motion precisely.\nThese nanocomposite hydrogels will provide strategies for wearable\nflexible sensors with superior stability and repeatability.