Phase-Separated Ductile Eutectogels with Excellent Environmental Durability and Antibacterial Features for Thermoelectric Response and Highly Sensitive Wearable Sensors

Hydrogels have found broad applications such as sensing and electrolytes; however, the insufficient sensing sensitivity, inherent environmental stability limitations, and poor mechanical properties hinder their further development in these areas. In this work, a multifunctional eutectogel with a rich hydrogen bond network and microphase-separated structure is prepared through one-step photopolymerization by mixing a binary deep eutectic solvent (DES) [zinc chloride (ZnCl₂) and ethylene glycol (EG)] with a polymerizable deep eutectic solvent (HCAG) [acrylic acid (AA), hydroxyethyl acrylate (HEA) and choline chloride (ChCl)]. This HCAG/DES gel exhibits a fracture stress of 2.25 MPa, toughness of 8.4 MJ/m³, self-healing efficiency of 86.4%, transmittance over 82%, and adhesive strength reaching 342 kPa. The eutectogel also exhibits notable thermoelectric conversion capability, generating a thermoelectric voltage of 78.3 mV under a temperature difference of 40 K. In addition, the eutectogel exhibits effective antibacterial activity against S. aureus and E. coli. The eutectogel-based strain sensors exhibit high sensitivity (GF up to 6.063) and a broad sensing detection range (0–600%) as well as fast response time (0.6 s). These combined features enable the eutectogel-based sensor to monitor movement and transmit encrypted signals at −20 °C, demonstrating potential for applications in flexible wearable electronics within low-temperature environments.