Fish Scale Biomimetic Multifunctional Antifreeze Organogel for Flexible Strain Sensor Applications

The applications of conductive hydrogels in the fabrication of wearable sensors have been highlighted in recent studies. However, water in traditional hydrogels is volatile at room temperature and readily frozen at subzero temperatures, resulting in material failure, which is critical in their practical applicability. In this paper, we prepared an organogel with sodium lignin sulfonate (Ls) and poly(vinyl alcohol) in a dimethyl sulfoxide and water dual-solvent system and embedded dense fish scale biomimetic clusters of silver nanospheres on the surface of the organogel to impart high electrical conductivity and mechanical and antimicrobial properties. The obtained organogel exhibited excellent mechanical strength (1.58 MPa stress and 680% tensile strain), freeze resistance (−90 °C), and antimicrobial activity (bacteriostatic rate of more than 98%). In addition, the electrical conductivity of the organic gel still reached a high value of 1.9 mS cm–1 at the ultralow temperature of −90 °C. Moreover, the organogel sensor exhibited high strain sensitivity and fast response to various human movements; therefore, it accurately monitored human movement signals and physiological signals. This study proposes a simple method to prepare multifunctional lignin-based antifreeze organogels for their application in complex flexible wearable electronic devices, opening prospects for lignin-based antifreeze organogels.