Environment‐Tolerant Conductive Eutectogels for Multifunctional Sensing

Abstract

Conductive hydrogels have shown significant potential in the realm of flexible electronics; however, using water as a solvent introduces problems such as low‐temperature freezing and water loss. One possible solution to address these limitations is replacing water with deep eutectic solvents (DES). In this study, the PHEAA–gelatin–MXene (PGM) eutectogels are constructed with poly(N‐hydroxyethyl acrylamide) (PHEAA) and gelatin as the main components, and MXene nanosheets are added as nanofillers. The PGM eutectogels exhibit exceptional tensile and compressive mechanical properties, including remarkable stretchability (940%), high strength (0.5 MPa), high toughness (1.39 MJ m−3), and impressive compressive strength (0.3 MPa at 80% strain). Additionally, the PGM eutectogels demonstrate excellent adhesion, anti‐freezing, and long‐term anti‐drying abilities. Moreover, the PGM eutectogels multifunctional sensors allow high sensitivity, which enables accurate real‐time and stable monitoring of human activities over a wide temperature range. Consequently, the PGM eutectogels hold great potential as candidates in fields such as flexible wearable devices, personal healthcare, and human–machine interfaces.

Tough, Transparent, and Wider-Temperature-Tolerant Deep Eutectic Hydrogels for Strain Sensing and Friction Nanogenerators

“…Table S1 summarizes the detailed data used in Figure c. ,,,,,− In addition, as shown in Figure d, the DES/water binary solvent endows PPDHA with excellent mechanical properties and high electrical conductivity, which is due to the fact that the DES/water binary solvent reduces the viscosity of the hydrogel, which facilitates ionic migration. Table S2 summarizes the detailed data used in Figure d. ,− ,,− To evaluate the fatigue resistance, we conducted 10 consecutive cycles of large strain (ε = 100, 300, and 500%) tensile experiments on PPDHA (Figures e and S5). The hydrogel effectively dissipates energy during the tensile cycling process, as evidenced by the hysteresis curves during cyclic loading, which were found to be nearly identical after the second tensile cycle.…”

“…Therefore, it is possible to prepare ion-conductive hydrogels with excellent temperature tolerance and conductivity in the DES solvent/water binary solvent system. 25 On the other hand, although various strategies have been reported for the synthesis of strong and tough hydrogels, such as the construction of dual-network structures, 26 the addition of nanomaterials, 27 metal ion coordination, 28 the Hofmeister effect, 29 and phase separation, 30 a single strategy often fails to achieve balanced performance. The double-network structure of hydrogels can effectively disperse stress and dissipate energy by introducing sacrificial bonds such as hydrogen and ionic bonds into the network, which improves flexibility.…”

“…The strain sensors showed relatively high sensitivity with a high gauge factor of 2.3 at 0–150% strain. Therefore, it is possible to prepare ion-conductive hydrogels with excellent temperature tolerance and conductivity in the DES solvent/water binary solvent system …”