One-Pot Fabrication of a Recyclable and Multifunctional Physically Crosslinked Eutectogel for Thermoelectric Supercapacitors and Strain Sensing.

This study reports a transparent and robust PVA-based eutectogel prepared by a simple one-pot method using a ternary CC/Im/EG deep eutectic solvent system. The addition of EG lowers the liquidus temperature of the binary solvent and enables gel formation at room temperature. FTIR confirms that the eutectogel network is physically crosslinked without new chemical bond formation, allowing thermal recyclability. Structural analyses, including XRD, SAXS, and SEM, show that increasing the PVA content promotes the formation of denser microcrystalline domains and a more compact network structure, thereby improving the mechanical performance of the eutectogels. The eutectogel containing 15 wt % PVA achieves a tensile strength of 1.46 MPa, a toughness of 0.24 MJ m-3, and excellent structural recovery after 8 h. It also exhibits outstanding ionic thermoelectric performance, with a high Seebeck coefficient of 8.6 mV K-1, an ionic conductivity of 10.3 mS cm-1, and an ionic figure of merit of 0.081. Moreover, the operating mechanism of the corresponding ionic thermoelectric supercapacitor is systematically elucidated. In addition, the soft eutectogel demonstrates stable strain-sensing performance. After thermal reprocessing, the recycled eutectogel retains reliable mechanical, thermoelectric, and sensing properties, highlighting its potential as a recyclable multifunctional material for flexible electronics.