Superior ultraviolet-shielding, recyclable, and conductive eutectogel for wearable sensing in extreme environments

Novel PLT eutectogel overcomes hydrogel susceptible to UV-induced damage and aging. • It provides long-term UV shielding while maintaining original performance. • TA cross-linking agent prevents depolymerization to boost mechanical stress. • It provides excellent temperature stability (60 °C) and low swelling in water/saline. • Reliable strain detection across extreme conditions (ambient, −20 °C, underwater). Gel-based materials hold significant promise for flexible electronics but are frequently limited by ultraviolet (UV) induced degradation, inadequate environmental tolerance, and modest mechanical robustness. To address these challenges, we develop a transparent, conductive, and biosafe poly(lipoic acid)-tannic acid eutectogel (PLT eutectogel) through a facile thermal polymerization-solvent exchange strategy. Tannic acid (TA) functions as a multifunctional stabilizer and cross linker, simultaneously suppressing the inherent depolymerization of the network and providing exceptional UV-shielding capacity via its polyphenolic structure. The resulting eutectogel exhibits an ultrahigh UV absorbance of 3.4 across the UVA and UVB regions, nearly completely shielding the full spectrum (200–400 nm). It also demonstrates robust mechanical properties (tensile strength: 3.68 MPa, fracture strain: 529%, tear energy: 0.566 kJ⋅m −2 ), excellent thermal and freezing resistance (83% mass retention at 60 °C, stable performance at −20 °C, no crystallization down to −90 °C), and low swelling in aqueous media (<40% in water, <38.5% in saline). Combined with an ionic conductivity of 2.46 mS⋅cm −1 , recyclability, biocompatibility, and antibacterial activity, the PLT eutectogel serves as a high performance sensing platform. As a proof of concept, a flexible strain sensor fabricated from this material reliably monitors human motions and enables underwater Morse code communication, illustrating its potential for durable human machine interfaces under extreme environmental conditions. Download: Download high-res image (99KB) Download: Download full-size image