Ultrastretchable Ionogel with Extreme Environmental Resilience through Controlled Hydration Interactions

Abstract

Ionic conductive gels are widely sought after for applications that require reliable ionic conduction and mechanical performance under extreme conditions, which remains a grand challenge. To address this limitation, water‐induced hydration interactions are deliberately controlled within the ionic liquid (IL)‐based conductive gels (ionogels) to achieve all‐round performance. Specifically, the competitive interactions between IL, water and cellulose nanofibrils (CNF) are balanced to preserve the nanoscale morphology of CNF while avoiding its dissolution. As a result, both mechanical performance and ionic conductivity of the resultant ionogel are synergistically enhanced. For instance, an ultra stretchable ionogel (up to 10250 ± 412% stretchability) with both high toughness (21.8 ± 0.9 MJ m−3) and ionic conductivity (0.70 ± 0.06 S m−1) is achieved. Furthermore, multimodal sensing functions (strain, compression, temperature, and humidity) are realized by assembling the ionogel as a skin‐like membrane. Due to the low volatility of IL and its strong interaction with water, the ionogel maintains an excellent performance at either ultra‐low temperature (−45 °C), high temperature (75 °C) or low humidity environment (RH < 15%), demonstrating superb anti‐freezing and anti‐drying performance. Overall, a simple yet versatile strategy is introduced that leads to environmentally resilient ionogels to meet the requirements of next‐generation electroactive devices.

Bio‐Inspired Multiscale Design for Strong and Tough Biological Ionogels

“…As shown in Figure 6e, the biomimetic M-gel had a high Young's modulus of 31.5 MPa, which was better than that of most previously reported gel materials. [9,[27][28][29][30][31][32] In addition, we could freely enlarge the size of this biomimetic M-gel according to the requirements of actual applications (Figure 6f).…”

An Ultrastretchable Gradient Ionogel Induced by a Self-Floating Strategy for Strain Sensing

“…The △ R / R 0 changes little in the low RH range of 11–33% and then gradually decreases to −17% as RH increases from 43% to 97% (Figure S4). This phenomenon could be attributed to the water absorption of the ionogel-based sensor, as water absorption enhances the ionic conductivity of the ion solvation and the ion mobility promoted by the combination between the water and the ionic liquids through ion–dipole interactions, as well as the reduction of the viscosity of the ionic liquids. , △ R / R 0 also decreases with increasing temperature due to the enhancement of the conductivity (Figure S5). Consequently, the signal stability of the prepared strain sensor needs to be improved in future studies.…”

Environmentally Stable, Robust, Adhesive, and Conductive Supramolecular Deep Eutectic Gels as Ultrasensitive Flexible Temperature Sensor

“…Previous studies have demonstrated that reducing the cross-linking density of the polymer network could also improve ionic mobility/conductivity. [22,23,31,32] In this sense, the thermal responsive supramolecular network might endow deep eutectic gel with outstanding temperature sensitivity due to the decreased cross-linking density with the increment of temperature. In our previously reported thermal responsive shape memory hydrogels, the dipole-dipole interactions between acrylonitrile (AN) and the hydrogen bonding interactions between acrylamide(AAm) could effectively enhance the mechanical properties of the copolymer hydrogels, and also collectively afforded excellent temperature responsiveness.…”