Lignosulfonate sodium and ionic liquid synergistically promote tough hydrogels for intelligent wearable human-machine interaction.

Flexible wearable devices are garnering significant interest, with conductive hydrogels emerging as a particularly notable category. While many of these hydrogels offer impressive conductivity, they often lack the innate ability to adhere autonomously to human skin. The ideal hydrogel should possess both superior adhesion properties and a wide responsive range. This study introduces a novel double-network conductive hydrogel, synthesized from lignosulfonate sodium and ionic liquid using a one-pot method. The gel's mechanical robustness (fracture elongation of ∼3500 % and tensile strength of ∼130 kPa) and exceptional conductivity sensing performance arise from the synergistic effects of electrostatic interactions, dynamic hydrogen bonding, and a three-dimensional network structure. Additionally, the phenolic hydroxyl and sulfonic groups from lignosulfonate sodium imbue the hydrogel with adhesive qualities, allowing it to easily bond with varied material surfaces. This hydrogel excels in human physiological signal detection and wireless monitoring, demonstrating a rapid response time (149 ms) and high sensitivity (a maximum gauge factor of 10.9 for strains between 400 and 600 %). Given these properties, the flexible, self-adhesive, and conductive hydrogel showcases immense promise for future applications in wearable devices and wireless transmission sensing.

TEMPO bacterial cellulose and MXene nanosheets synergistically promote tough hydrogels for intelligent wearable human-machine interaction.

Conductive hydrogels have received increasing attention in the field of wearable electronics, but they also face many challenges such as temperature tolerance, biocompatibility, and stability of mechanical properties. In this paper, a double network hydrogel of MXene/TEMPO bacterial cellulose (TOBC) system is proposed. Through solvent replacement, the hydrogel exhibits wide temperature tolerance (-20-60 °C) and stable mechanical properties. A large number of hydrogen bonds, MXene/TOBC dynamic three-dimensional network system, and micellar interactions endow the hydrogel with excellent mechanical properties (elongation at break ~2800 %, strength at break ~420 kPa) and self-healing ability. The introduction of tannic acid prevents the oxidation of MXene and the loss of electrical properties of the hydrogel. In addition, the sensor can also quickly (74 ms) and sensitive (gauge factor = 15.65) wirelessly monitor human motion, and the biocompatibility can well avoid the stimulation when it comes into contact with the human body. This series of research work reveals the fabrication of MXene-like flexible wearable electronic devices based on self-healing, good cell compatibility, high sensitivity, wide temperature tolerance and durability, which can be used in smart wearable, wireless monitoring, human-machine Interaction and other aspects show great application potential.