Liquid‐Free, Anti‐Freezing, Solvent‐Resistant, Cellulose‐Derived Ionic Conductive Elastomer for Stretchable Wearable Electronics and Triboelectric Nanogenerators

Abstract

The development of flexible conductive elastomers integrating renewable feedstock, splendid mechanical property, and excellent weather resistance is of major interest and challenge. Here, a novel strategy is reported to construct the liquid‐free cellulose‐derived ionic conductive elastomer that is successfully applied in the wearable sensor and triboelectric nanogenerators (TENG). In this strategy, the ionic conductive elastomer with physical and chemical dual‐crosslinking network is prepared via in situ polymerization of the polymerizable deep eutectic solvent. The construction of dual‐crosslinking network improves the mechanical strength and toughness more than 2 times, and the cellulose contributes to forming the dense hydrogen bond crosslinking network that can improve the recyclability, anti‐freezing, and solvent‐resistance performance. Benefiting from these features, the ionic conductive elastomer is successfully applied in the wearable sensors and TENG for monitoring human motion, and in harvesting mechanical energy to convert into stable electrical outputs to light the LEDs, charge the capacitor, and power the electronic watch. The ionic conductive elastomer maintains reliable sensing and energy harvesting performance even after recycling, soaking in organic solvent, or at low/high temperature. This study paves a promising strategy for fabricating sustainable and multifunction flexible electronics that are suitable for harsh environments.

Flexible Quantum Dot Light‐Emitting Device for Emerging Multifunctional and Smart Applications

“…[ 46,82,84–88 ] The main approach to achieving flexibility/stretchability is to substitute rigid conductive layers with nanomaterials such as graphene and nano silver, [ 89–95 ] and rigid glass/silicon substrates with carbon‐based polymers. [ 96–98 ] Consistent with the designing principles of other electronic devices transforming from rigid to flexible, QLEDs are expected to maintain electronic/optical properties during the flexible evolution. In addition, the advances in QLEDs stimulate emerging applications beyond simple light and display.…”

“Deep Eutectic Solvent-in-Water” Hydrogels Enable High-Performance Flexible Strain Sensors for Electronic Skin with a Wide Operating Temperature Range

“…24−26 Gels fabricated using deep eutectic solvents (DES) are more economical, biocompatible, resistant to extreme temperatures, and less toxic than traditional hydrogels and ionic liquids. 27 Gels of DESs were currently investigated in sensors, 28 capacitors, 29 and batteries. 30 Despite the high safety, better electrochemical stability, and low cost, gels made of DES still suffer from low ionic conductivity.…”

“…Typically, by fabricating the “ionic liquid-water” hybrid gels, the formation of ice crystals can be efficiently inhibited, , whereas ionogels made of ionic liquids (ILs) are not biocompatible, of high cost, or even toxic. − Gels fabricated using deep eutectic solvents (DES) are more economical, biocompatible, resistant to extreme temperatures, and less toxic than traditional hydrogels and ionic liquids . Gels of DESs were currently investigated in sensors, capacitors, and batteries . Despite the high safety, better electrochemical stability, and low cost, gels made of DES still suffer from low ionic conductivity.…”

Novel Lignin Hydrogel Sensors with Antiswelling, Antifreezing, and Anticreep Properties

“…Flexible wearable electronic devices have attracted a significant amount of interest in the fields of human motion detection, health monitoring, electronic skins, flexible sensors, and soft robotics because of their large mechanical flexibility and their ability to adapt to different working environments to a certain extent and meet different deformation requirements. − Among a wide variety of sensing materials, hydrogels show great application potential due to their functionality, formability, and chemical editability. − Although the application value of hydrogel sensors in detecting body movement and vital signs has been proven, their practical application is still significantly limited, which is mainly caused by the inherent properties of hydrogels. − The first inherent property that hinders the practical application of hydrogels as flexible wearable electronic devices is swelling behavior. Hydrogel is a kind of soft material composed of a three-dimensional polymer framework with high water content. − For obtaining good biocompatibility, this three-dimensional polymer framework is generally designed as hydrophilic polymer segments, which will lead to the swelling behavior of the hydrogel in the aqueous environment. − Swelling behavior is usually accompanied by the introduction of a large number of solvent substances and the dilution or loss of functional molecules. − Meanwhile, the decrease of hydrogel density caused by swelling behavior also has a significant negative impact on the mechanical properties of hydrogels. − The second inherent property is the low-temperature phase transition behavior of hydrogels.…”