Highly Stretchable, Self-Adhesive, Antidrying Ionic Conductive Organohydrogels for Strain Sensors

Area of Science:

• Soft electronics
• Materials science
• Biomedical engineering

Background:

• Hydrogel sensors are crucial for flexible wearable devices but struggle with stability at extreme temperatures.
• Conventional hydrogels' water content limits their performance in freezing or drying conditions.

Purpose of the Study:

• To develop novel antifreezing and antidrying ionic conductive organohydrogels.
• To create stable and durable hydrogel-based wearable sensors for human motion monitoring.

Main Methods:

• Utilized cellulose nanocrystals and gelatin as raw materials.
• Employed a one-pot method with a water/glycerol binary solvent.
• Characterized hydrogels using scanning electron microscopy and Fourier transform infrared spectroscopy.
• Evaluated mechanical, electrical, and sensing properties via universal material testing machine and LCR digital bridge.

Main Results:

• Achieved high stretchability (584.35% elongation at break) and firmness (0.16 MPa).
• Demonstrated excellent freezing and drying resistance (7 days) due to strong hydrogen bonding in the binary solvent.
• Maintained stable conductivity and sensitivity across a wide temperature range (-50 °C to 50 °C) and storage duration.
• Developed wearable sensors with a gauge factor of 6.47 (0-400% strain) capable of detecting human motions.

Conclusions:

• Developed multifunctional organohydrogel wearable sensors possess excellent antifreezing and antidrying properties.
• These sensors show significant potential for reliable human body monitoring across diverse environmental conditions.
• The novel hydrogel composition ensures long-term stability and consistent performance for wearable electronic applications.