Macromolecular Solvent‐Based Durable Gel With Self‐Bonding and Adhesive for Long‐Lasting Flexible Electronics

ABSTRACT Hydrogels, particularly adhesive hydrogels, garner increasing attention for applications in flexible electronics. However, their susceptibility to water evaporation undermines long‐term stability in everyday environments. Moreover, the adhesive properties of most existing adhesive hydrogels depend on specific adhesive groups, such as dopamine and nucleobases, which restrict the versatility of gel design. This work designs a gel by replacing water with PEG‐modified polydimethylsiloxane as the macromolecular solvent and introduces anionic monomers to regulate its mechanical properties, self‐bonding capability, and adhesion performance. The anionic monomers reduce hydrogen bonding via interchain repulsion, lowering stress and modulus, though elongation decreases slightly. The modified gel shows reduced hysteresis, enhanced fatigue resistance, and unchanged mechanical properties after 90 days, demonstrating long‐term durability. It also exhibits strong self‐bonding and versatile adhesion, enabling reliable attachment to diverse substrates, including skin. Flexible sensors made by integrating the gel with liquid metal display high sensitivity, low‐strain detection, and stable performance after 90 days. The skin‐adhesive sensor effectively monitors joint movements and respiratory rates. This work highlights the potential of polymer solvent‐based systems as alternatives to aqueous solutions for developing gel materials in flexible electronics, while its scalable design and durability offer new perspectives for future wearable device engineering.