Owing to wearing and unpredictable damage, the working lifetime of triboelectric nanogenerators (TENGs) is largely limited. In this work, we prepared a single-electrode multifunctional TENG (MF-TENG) that exhibits fast self-healing, human health monitoring capability, and photothermal properties. The device consists of a thin self-healing poly­(vinyl alcohol)-based hydrogel sandwiched between two self-healing silicone elastomer films. The MF-TENG exhibits a short-circuit current, short-circuit transfer charge, and open-circuit voltage of 7.98 μA, 78.34 nC, and 38.57 V, respectively. Furthermore, owing to the repairable networks of the dynamic imine bonds in the charged layer and the borate ester bonds in the electrodes, the prepared device could recover its original state after mechanical damage within 10 min at room temperature. The MF-TENG can be attached to different human joints for self-powered monitoring of personal health information. Additionally, the MF-TENG under near-infrared laser irradiation can provide a photothermal therapy for assisting the recovery of human joints motion. It is envisaged that the proposed MF-TENG can be applied to the fields of wearable electronics and health-monitoring devices.

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In this work, graphene nano-sheets (GNS) functionalized with poly(dopamine) (PDA) (denoted as GNS-PDA) were dispersed in a carboxylated nitrile butadiene rubber (XNBR) matrix to obtain excellent dielectric composites via latex mixing. Because hydrogen bonds were formed between –COOH groups of XNBR and phenolic hydroxyl groups of PDA, the encapsulation of GNS-PDA around XNBR latex particles was achieved, and led to a segregated network structure of filler formed in the GNS-PDA/XNBR composite. Thus, the XNBR composite filled with GNS-PDA showed improved filler dispersion, enhanced dielectric constant and dielectric strength, and decreased conductivity compared with the XNBR composite filled with pristine GNS. Finally, the GNS-PDA/XNBR composite displayed an actuated strain of 2.4% at 18 kV/mm, and this actuated strain was much larger than that of pure XNBR (1.3%) at the same electric field. This simple, environmentally friendly, low-cost, and effective method provides a promising route for obtaining a high-performance dielectric elastomer with improved mechanical and electrochemical properties.

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