Strong and Ultratough Ionogel Enabled by Ingenious Combined Ionic Liquids Induced Microphase Separation

Abstract

Ionogels have become a popular material in flexible electronics and soft robotics based on their excellent ionic conductivity, environmental tolerance, and electrochemical stability. However, it remains a challenge to develop an ionogel integrated with high strength, toughness, self‐healing, and adhesion. Herein, a novel strategy is established to design a high‐strength (0.97 MPa) and tensile (980%), excellent crack insensitivity, self‐healing ionogel based on the cosolvent method. By virtue of differential interactions between the specific polymer and various ionic liquids with gradient polarity, cosolvent systems are employed to achieve high‐performance ionogels by a simple one‐step polymerization. Gel permeation chromatography, atomic force microscopy, time‐domain nuclear magnetism, and density functional theoretical calculation are used to analyze the reasons. Microphase separation can be induced by hydrone or stretching to enhance strength of the ionogel. Therefore, ionogels can be assembled as strain and temperature sensors to monitor human movement and person's body temperature with a low detection threshold (0.1 °C) in extreme environments. This concept creates a new path to achieve soft materials with high performance, and provide a prospective strategy to regulate the in situ microphase change and performance of the resulting ionogel via the one‐step polymerization.

Simultaneously enhancing the mechanical robustness and conductivity of ionogels by in situ formation of coordination complexes as physical crosslinks

“…The lag decreased slightly with the number of cycles, possibly due to the un-recovery of dynamic bonds with partial dissociation in the rst cycle. 26 Notably, aer standing at room temperature for 1 h (Fig. 3i and j), the energy dissipation of the sample returned to almost 95% of the rst cycle, indicating good elastic recovery with recovery ability varying over time.…”

“…Our tough ionogels are positioned in the rightmost area of the plot, indicating that they possess superior fracture strength compared to the best-in-class conductive ionogel while maintaining competitive ionic conductivity. 26,[30][31][32][33][34][35][36][37] This highlights the unique design and excellent properties of our ionogels.…”

Self-adaptive high-temperature gels with long-lasting underwater stability for environmentally tolerant flexible sensors and water-writing papers

“…24–26 Consequently, IL-based gels are selected as flexible sensors that can demonstrate advantageous stability and repeatable output of the electrical signal in a wide temperature range. 27–29 Notably, He and co-workers fabricated a highly stretchable and repeatable ionogel by using the ionic liquid (IL) 1-ethyl-3-methylimidazolium thiocyanate as the dielectric, which could be used as a wearable sensor to effectively detect various human motions and special limb movements, such as Tai Chi. 30 Wang et al successfully developed an ionogel sensor for a wearable intelligent health monitoring system capable of monitoring health-related physiological signals, such as breathing, wrist pulse, body tremors, and temperature.…”

Rapid self-healing and superior toughness in ionically crosslinked polymer ionogels and strain sensing applications

“…The dynamic and reversible process of hydrogen bonding contributed to energy dissipation and network reconstruction in the ionogel, which provided ionogel with fast self-healing ability, high tensile strength, and good ionic conductivity. 17–21 We have also explored the effect of Ca-ion incorporation within the polymer matrix on self-healing and mechanical properties, which resulted in an increase in ionic conductivity but a slight decrease in rigidity and healing performance. NaCl or LiCl was avoided to prevent the ionogel from absorbing moisture from air.…”