Construction of Multifunctional Hydrogels via a Supramolecular Self-Assembled Strategy with Ultrahigh Sensitivity to Strain Responsiveness

Intelligent electronic devices have been diffusely used in health detection, energy storage, and biomedicine based on their autonomy, flexibility, and adaptive improvement, but traditional materials have the drawbacks of limited flexibility, instability, and inadequate reusability. Herein, poly(acrylic acid)-based hydrogels with efficient self-healing performance and high-precision sensing performance were constructed by a supramolecular self-assembled strategy based on electrostatic interactions, metal coordination, and hydrogen bonds. This hydrogel exhibited a tensile strength of 102.9 kPa and an elongation at break of 990% with good fatigue resistance and self-recovery ability. The hydrogel also displayed good light transmission and UV-shielding effects, as well as good adhesion ability on different materials. Besides, the hydrogel had an electrical conductivity of 0.98 S/m, which could light up a light-emitting diode (LED) bulb when connected in a circuit. Based on these great features, the hydrogel exhibited ultrahigh sensitivity with gauge factor values of 4.00 and 17.00 within the strain ranges of 0-200 and 600-800%, respectively. The hydrogel could be applied not only for large human movements but also for detecting subtle movements. Most importantly, the hydrogel exhibited a great self-healing property, which could almost self-heal within 6 h with a healing efficiency of 99%. Therefore, this work provides a multifunctional hydrogel construction method, and the prepared hydrogels displayed great potential application in the strain sensor field.