Phase-Separated Ductile Eutectogels with Excellent Environmental Durability and Antibacterial Features for Thermoelectric Response and Highly Sensitive Wearable Sensors
Yao Song, Boxuan Zhang, Shen Hu, Hexin Zhu, Huijie Hu, Kunlin Chen, Yanyan Li, Peng Gu
Abstract
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 (ZnCl 2 ) 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/m 3, 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.