Multiperformance\nFully Physically Cross-Linked Organogel\nfor All-Climate Wireless Human Motion Sensors and Water Writing Paper

Conductive\norganogels are considered ideal materials\nfor the fabrication\nof flexible wearable electronic devices. However, the simultaneous\nrealization of epidermal electronic devices with excellent self-healing,\nself-adhesion, multienvironment tolerance, and superior sensing performance\nremains a formidable challenge. In this study, a multiperformance\nconductive organogel was synthesized via a one-step photopolymerization\nof acrylic acid (AA) and acrylamide (AAm) in an H<sub>2</sub>O/glycerol\n(Gly) solution comprising gelatin and Al<sup>3+</sup> ions, utilizing\nzinc dimethacrylate (ZDMA) containing Zn<sup>2+</sup>-carboxyl coordination\nbonds as an ionic cross-linker. The physical cross-linked gelatin/P(AA-<i>co</i>-AAm-<i>co</i>-ZDMA)/Al<sup>3+</sup> organogel\nwas formed through the synergistic effects of multiple hydrogen bonding,\ndual ionic coordination bonds, and physical entanglement among diverse\nmacromolecular chains. The prepared organogel exhibited superior toughness\n(387 kPa), significant self-healing ability (633% strain for the healed\norganogel), prominent moisture retention (weight retention of 80%\nafter 15 days), and remarkable long-term temperature resistance. Without\nsealed packaging, the organogel maintained excellent mechanical properties\neven after exposure to different temperatures (−30 °C,\n20 °C, and 50 °C) for durations of 15, 15, and 7 days, respectively.\nThe strain sensor based on the gelatin/P(AA-<i>co</i>-AAm-<i>co</i>-ZDMA)/Al<sup>3+</sup> organogel exhibited excellent sensitivity\n(gauge factor, GF = 3.36), outstanding signal stability (600 cycles\nat 60% strain), and precise monitoring of underwater motion. The wireless\nheart monitoring system integrated with the organogel sensor was affixed\nto the left chest of volunteers for real-time detection of minute\nhuman electrocardiograph (ECG) signals. More notably, the synthesized\norganogel exhibited a pronounced alteration in transmittance upon\nexposure to water and glycerol, rendering it suitable for application\nas a reusable water writing paper for recording and erasing information.\nThe multifunctional organogel exhibits great promise for the development\nof future flexible electronics with enhanced environmental adaptability.