3D printing of microstructured polyacrylamide/sodium alginate/lithium chloride composite hydrogels for nanofriction generator and e-skin.

The development of wearable electronic devices presents significant challenges to develop flexible power supplies and sensors that are efficient and convenient, highly sensitive, and adaptable to complex environments. In this study, dual-network ionic PSL hydrogels were successfully synthesized and characterized, which have excellent cyclic tensile properties (maximum stress fluctuation <8 % over 50 tensile times), anti-freezing (-47.2 °C), electrical conductivity (175.8 S/cm), and sensing properties (the highest GF value is 0.82). Leveraging the favorable the good rheological properties of PSL hydrogels, a quadrangular cone hydrogel-based TENG with ultra-high sensitivity (75.65 mV Pa) was constructed by 3D printing. Under continuous impact excitation, the PSL-QTENG is capable of generating an open-circuit voltage of up to 201.4 V and powering to 100 LEDs. Furthermore, the PSL-QTENG has been demonstrated to power a thermo-hygrometer, which has the potential to be used in the fields of mechanical energy harvesting, human motion monitoring, human-computer interaction, and self-powered electronic skin.