Tough, Adhesive, and Ionically Conductive Hydrogels via Digital Light Processing 3D Printing as Wearable Sensors

However, current systems still face challenges in simultaneously achieving printability, mechanical robustness, electrical conductivity, and interfacial adhesion. In this study, an ionically conductive hydrogel system based on poly(vinyl alcohol) (PVA), polyacrylamide (PAM), tannic acid (TA), and glycerol (Gly), denoted as PATG, was fabricated by digital light processing (DLP) 3D printing.

The hydrogel exhibited excellent mechanical properties, including a fracture strain of 480%, a tensile strength of 271 kPa, and a tensile toughness of 550 kJ m^–3. It also achieved a compressive toughness of 90 kJ m^–3 at 90% compressive strain and maintained structural stability after 100 compression cycles. Furthermore, the PATG hydrogel showed an electrical conductivity of 1.082 S m^–1 and a segmented linear response over 0–480% tensile strain, with a maximum gauge factor of 13.73.