Facile spinning of tough and conductive eutectogel fibers via Li⁺-induced dense hydrogen-bond networks

Tough conductive eutectogel fibers synthesized based on deep eutectic solvents (DESs) have attracted increasing attention in fields of flexible/stretchable electronics, due to their promising stretchability, mechanical strength, conductivity, and relatively inexpensive cost. However, it is still challenging to fabricate such high-performance eutectogel fibers in a simple and versatile strategy. Here, we report a facile spinning of tough conductive eutectogel fibers based on one-pot photopolymerization and Li⁺-induced toughening effect. This photopolymerization allows the formation of eutectogel into a long fiber format within seconds. The introduction of Li salt into the DESs can regulate the hydrogen bonding interactions, which can significantly promote the construction of a dense interchain hydrogen-bonding network in the eutectogel. Consequently, the spun eutectogel fibers exhibit outstanding Young's modulus (103.8 MPa), high toughness (38 MJ/m³), promising stretchability (>300 %), conductivity (6 × 10^-3 S/m), and good thermal stability at high temperature. The mechanical properties of the resultant eutectogel fibers can also be modulated by varying the DESs constituents. We demonstrate the multifunction of the fibers in shape-memory behavior, strain sensing, and recyclability. This facile spinning strategy offers a promising way to develop super-strong and conductive gel fibers as smart materials for diverse flexible and wearable device applications.