A multifunctional sustainable ionohydrogel with excellent low-hysteresis-driven mechanical performance, environmental tolerance, multimodal stimuli-responsiveness, and power generation ability for wearable electronics

摘要

The defects of conductive hydrogels, such as high internal friction, poor performance at freezing temperatures, and long-term evaporation during storage, restrict their application in wearable electronics. Herein, a dual-crosslinked starch/PAM/borax/glycerol ionohydrogel is fabricated through a one-pot gelation-assisted polymerization approach. Starch supports PAM adapting to the glycerol/water binary solvent system through hydrogen-bonding interactions and graft copolymerization, while boronic ester linkages serve as cross-linking sites. Interestingly, the ionohydrogel exhibits extremely low internal friction (0.5 kJ m(-3)) and excellent environmental tolerance over a wide temperature range (-60-80 degrees C). Strikingly, the ionization of Na2B4O7 is sensitive to variations in temperature and humidity in a binary solvent system, which also facilitates the ionohydrogel achieving a lower freezing point and higher evaporation temperature. The ionohydrogel achieves appreciable conductivity (21.1 mS m(-1)) and good mechanical properties (tensile strength: 332 kPa; elongation at break: 514%) at -40 degrees C. Taking advantage of these exceptional characteristics and stable transport channels for Na+ and B(OH)(4-), an assembled sensor can effectively detect variations in humidity (20-98%), temperature, and strain with high sensitivity, simulating the sensitivity of human skin. It is noteworthy that a single-electrode TENG manufactured using the ionohydrogel displays excellent energy-harvesting capabilities under different types of deformation. This work provides an effective strategy for obtaining a multifunctional ionohydrogel with high Delta R/R-0 sensitivity for utilization in self-powered wearable electronics under extreme environmental conditions.

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