Phytic Acid-Enhanced Superstretched, Self-Adhesive, Antifreeze Conductive Hydrogels for Motion Monitoring and Human–Computer Interaction

Hydrogels have become an important material in the field of wearable flexible electronics owing to their excellent flexibility and adjustable conductivity. However, due to the large amount of free water contained within the hydrogel, it freezes in low-temperature environments, resulting in poor conductivity and mechanical properties. In this study, an ionically conductive hydrogel was developed by introducing phytic acid (PA), a biomass-based antifreezing material. The addition of PA improved the mechanical, adhesion, and electrical properties, as well as the frost resistance of the hydrogel. The PAM/PVA0.15/Gelatin0.02/PA4 hydrogel prepared in this study exhibited an ultrahigh tensile strain (3083%), excellent adhesion (with adhesion strength to pig skin up to 448.45 kPa), and high conductivity (10.07 S m–1). At the same time, PA endowed the hydrogel with good frost resistance and long-term environmental stability. The hydrogel could remain soft even at −20 °C, as well as retain good electrical properties. In addition, an integrated hydrogel sensor exhibited a wide strain response range (1–1000%), excellent stability, and high sensitivity. Moreover, hydrogel sensors were also successfully used for motion and pipeline flow rate monitoring, as well as simple human–computer interaction applications.