Strong–Weak Response Network-Enabled Ionic Conductive Hydrogels with High Stretchability, Self-Healability, and Self-Adhesion for Ionic Sensors

Abstract

The requirement of ionic conductive hydrogels with tailor-made superelasticity and high chain mobility is highly desired while meeting a challenge. Herein, ionic conductive hydrogels with the design of strong–weak response networks were synthesized via the free-radical copolymerization of monomers of 1-methyl-3-(4-vinylbenzyl)­imidazolium chloride and sodium 2-acrylamino-2-methylpropanesulfonate in water. The as-formed strong–weak response networks in ionic conductive hydrogels included binary interactions of strong electrostatic forces and weak hydrogen bonds. The electrostatic forces imparted excellent mechanical elasticity, and the hydrogen-bonded interactions served as highly active and reversible networks to dissipate fracture energy during the deformation. Importantly, the resultant ionic conductive hydrogels exhibited high toughness of ∼2205 kJ m–3, satisfying fatigue resistance, and excellent healing efficiency of >90%. Moreover, the tailoring of counterion concentrations in hydrogels by adding various concentrations of inorganic salts could regulate the electrostatic forces within hydrogels as well as the finally mechanical strengths. Ascribing to the combination of large stretchability and large chain mobility, the resultant ionic conductive hydrogels could directly act as a stretchable ionic conductor for the assembly of self-healable and self-adhesive capacitance-type ionic sensors which are capable of detecting large and tiny human activities. This study could offer a promising strategy for the design and manufacturing of emerging ionic conductors with high mechanical elasticity and large segment mobility.

A κ-Carrageenan-Containing Organohydrogel with Adjustable Transmittance for an Antifreezing, Nondrying, and Solvent-Resistant Strain Sensor

“…As shown in Figure a and b, within the small (5–15%) and large (100–500%) strain ranges, the organohydrogel sensor could achieve the repeated relative resistance variation values (Δ R / R 0 ) at the same tensile strain and then return to the pristine values after releasing. Meanwhile, the assembled sensor exhibited a satisfactory sensitivity to strain stimuli, and the maximum gauge factor (GF) value could reach 1.8 (Figure c), which was comparable to the gel polymer-based strain sensors reported recently. − In Figure S7, it can be seen that the relative resistance changes were able to synchronize with strains. Meanwhile, the response time and recovery time of the organohydrogel sensor at the 15% strain were explored by the quick loading–unloading process.…”

Ultra-stretchable, Antifatigue, Adhesive, and Self-Healing Hydrogels Based on the Amino Acid Derivative and Ionic Liquid for Flexible Strain Sensors

“…The GF values of the sensor in the strain ranges of 0–100% and 100–200% were 1.6 and 3.7, respectively. Compared with other hydrogels in Table S1, the P­(MArg-FHVI-AA) hydrogel had ultra-stretchability and adhesive strength. ,,,, …”

“…Compared with other hydrogels in Table S1, the P(MArg-FHVI-AA) hydrogel had ultra-stretchability and adhesive strength. 6,30,31,55,56 ■…”

3D-Printed Photocurable Resin with Synergistic Hydrogen Bonding Based on Deep Eutectic Solvent

“…The healing PCRs exhibited Young’s modulus values in the range of 2.4–3.5 GPa, generally remaining consistent with the predamaged samples. The self-healing ability could be ascribed to the cooperative effects of hydrogen bonding and accelerated diffusion of the polymeric chains in the polymer at high temperatures . Although mechanical degradation was observed after the self-healing process, the parts from DES-based PCRs retained more than 50% of their original ultimate tensile strength (Figure b).…”

“…The self-healing ability could be ascribed to the cooperative effects of hydrogen bonding and accelerated diffusion of the polymeric chains in the polymer at high temperatures. 43 Although mechanical degradation was observed after the self-healing process, the parts from DES-based PCRs retained more than 50% of their original ultimate tensile strength (Figure 3b). Among various printed constructs, PCR-1/4/1 exhibited the highest healing efficiency of 75.9%, which was slightly lower than those of previously reported soft hydrogels and elastomers.…”