Soft Electronics Based on Liquid Conductors

Abstract

Soft electronics is an emerging field that is lending great convenience to daily life. Soft electronics have shown great potentials in health monitoring, soft robotics, the Internet of Things, and so forth. Though soft electronics based on solid conductors have been intensively investigated and some considerable progress has been achieved, the intrinsic shortcomings of solid conductors are becoming the Achilles’ heel of soft electronics. Fortunately, many of the disadvantages of solid conductors can be offset by liquid conductors. Following the attractive advantages of liquid materials, in particular high flexibility, infinite deformability, self‐healing, and ease of doping/being doped, this review article summarizes a history of soft electronics based on liquid conductors and introduces the most up‐to‐date liquid conducting materials together with their representative featured functions. Particular applications in sensors, batteries, supercapacitors, thermoelectric conversion, and even memory devices are discussed in detail to intuitively emphasize how liquid conductors benefit soft electronics. In addition, limitations of liquid conductors are also discussed, as well as the key challenges and some innovative strategies to overcome them. Finally, future perspectives are put forward to develop soft electronics that are fully composed of liquid circuits.

Skin-Inspired Healable Conductive Elastomers with Exceptional Strain-Adaptive Stiffening and Damage Tolerance

“…This result indicates that the PU−Zn−IL elastomer mainly undergoes recoverable elastic deformation during this process. In contrast, as the strain further increases, the hysteresis area increases rapidly, meaning that obvious and 32,37 Upon stretching the PU−Zn−IL elastomer to 600% strain or further, new scattering signals perpendicular to the tensile direction were observed in the 2D-SAXS patterns (Figure 4c-iii,iv). 21,34,37 Meanwhile, a new diffraction peak at 2θ = 21.5°appears in the WAXD patterns, which corresponds to the 110 plane of PCL crystals (Figure S10a, Supporting Information).…”

“…Figure S9 shows that the PU−Zn− IL conductive elastomer exhibits highly reversible and repeatable resistance changes under 0.5, 1, 5, and 10% strains, indicating its excellent strain sensing ability. 32,33 3.3. Structure of the PU−Zn−IL Elastomer.…”

“…Considering its high mechanical strength and its excellent extensibility, elasticity, and thermomechanical stability, the PU–Zn–IL elastomer is believed to be suitable for use in strain sensors, stretchable electrodes, and wires for a large variety of flexible devices. Figure S9 shows that the PU–Zn–IL conductive elastomer exhibits highly reversible and repeatable resistance changes under 0.5, 1, 5, and 10% strains, indicating its excellent strain sensing ability. , …”

Organic ionic fluid-based wearable sensors for healthcare

“…1). 7,[15][16][17][18] In particular, organic ionic fluids exhibit excellent affinity and solubility towards polar molecules, which are widely regarded as desired recognition and sensing platforms for biomarkers. 19,20 It should not be ignored that organic ionic fluids also potentially confer unique device manufacturing processes due to their fluidity.…”

Research progress in ionic liquid-based multifunctional green electronic devices

“…。此外，基 于液态离子导体开发的绿色电子器件不仅具 备良好的电学性能，还同时具备传统固态电 子材料所缺乏的柔性、自修复性、可重塑性 以及可重构性等性能 [9] [10,11] 。离子液体 常见的阳离子主要有单取代或二取代的咪唑 阳离子、季鏻阳离子、季铵阳离子和吡啶阳 离子，阴离子则主要包括卤素离子、醋酸根 离子、四氟硼酸根离子、六氟磷酸根离子以 及双三氟甲基磺酰亚胺盐等。离子液体的特 殊结构赋予其良好的可设计性 [12] ，能够通过 阴阳离子的结构设计引入不同的功能基团从 而满足特定的目标需求，为绿色的液体电子 器件的功能拓展与器件集成提供了可能 [13]…”