Multi-network hydrogel-based stretchable, self-adhesive, and self-healing self-powered flexible sensors for multi-scale, dynamic and static strain/pressure sensing

Hydrogel-based flexible sensors show great promise for applications. However, conventional hydrogel sensors suffer from poor mechanical properties, lack of self-repair and self-adhesion, narrow detection range, low sensitivity, and external power supply limitations. Herein, a strain/pressure sensor based on a multinetwork hydrogel (polyacrylamide/krill protein/sodium alginate-Zn 2 + (PAAm/AKP/Alg-Zn 2+ ), PKAZ) is proposed to cope with the above challenges. PKAZ has desirable tensile properties (1694.14 %, 0.65 MPa), compressibility (80 % compressive strain of 1.32 MPa), reversible adhesion, thermally induced self-healing capability, and high electrical conductivity (3.63 S m −1 ). The fabricated strain/pressure sensor also exhibited a wide detection range (strain: 10 %-1100 %, pressure: 1kPa-50kPa) and high sensitivity (strain: GF = 6.67, pressure: S = 0.35 kPa −1 ). More importantly, the hydrogel can also be constructed with Cu/Zn electrodes to form electrochemical self-powered sensors (PKAZES) for sensitive monitoring of dynamic and static strain/pressure without needing an external power supply. Such sensors have promising applications in identifying and differentiating pressure intensities, speech recognition, electrocardiograms, swallowing behavior, and sitting and static pressure testing.