Tunable gelatin/carrageenan interactions enable balanced toughness and conductivity of double-network eutectogels for sensitive strain sensors

In the realm of flexible electronics, eutectogels have emerged as a highly promising material, outperforming hydrogels in environmental tolerance and surpassing ionogels in biosafety and economic affordability. These attributes have positioned eutectogels as a burgeoning choice for the development of multifunctional flexible devices. However, as a relatively new material, achieving optimal mechanical and electrical properties in eutectogels through conventional preparation methods has proven challenging, primarily due to the extensive hydrogen bonding present in deep eutectic solvents. To address this challenge, we incorporated natural macromolecules, specifically gelatin and carrageenan, into a polyacrylamide matrix to create a double-network eutectogel. The addition of carrageenan significantly enhanced the mechanical properties of the gel by promoting the formation of a robust hydrogen bond network among gelatin molecules. This innovation dramatically enhanced in the gel's performance, with a tensile strength of 2.58 MPa and toughness of 17.6 MJ/m 3 , representing increases of 32.3 times and 17.9 times, respectively, compared to the gel without carrageenan. Moreover, these eutectogels achieved high electrical conductivity (2.29–3.62 mS/cm) through hydrogen bonding interactions. The critical role of carrageenan in strengthening the mechanical network highlights its potential as a key component in the development of mechanically robust, ionic-conducting, and anti-freezing high-performance wearable sensors. This work not only overcomes the limitations of existing materials but also paves the way for the next generation of wearable sensors with enhanced durability and functionality.