Ionic Network Based on Dynamic Ionic Liquids for Electronic Tattoo Application

Abstract

Electronic tattoos as an emerging epidermal electronic are alluring in the field of wearable electronics for their lightweight and noninvasive properties. However, the combination of flexibility, skin biocompatibility, adhesion, repairability, and erasability remains a challenge for fabricating electronic tattoos. Hence, a dynamic ionic liquid is prepared which is ideally suited for making an electronic tattoo with these challenging features at the same time. Such an intrinsically flexible electronic tattoo can be firmly attached to human skin with negligible irritation. More importantly, the existence of dynamic covalent chemistry provides the electronic tattoo with healing and erasable abilities under mild redox conditions. Owing to the high ionic conductivity of ionic liquids, the electronic tattoo exhibits excellent sensing performance in response to the temperature variation and tensile strain, which can intelligently monitor body temperature, pulse, and movement. As an extension of the application, a specially designed quadrilateral electronic tattoo can sense and distinguish multiple signals simultaneously. This concept of electronic tattoo based on the dynamic ionic liquid shows great potentials in the applications of intelligent wearable electronics.

Organic ionic fluid-based wearable sensors for healthcare

“…The mechanoelectric mechanism is to transform the strain or pressure stimulation caused by pulse vibration into corresponding electrical signals by resistive or capacitive sensors. 78,85 Compared with resistive sensors, capacitive sensors show…”

“…The mechanoelectric mechanism is to transform the strain or pressure stimulation caused by pulse vibration into corresponding electrical signals by resistive or capacitive sensors. 78,85 Compared with resistive sensors, capacitive sensors show Sensors & Diagnostics Critical review higher sensitivity in detecting weak vibrations caused by pulse. Pan's group developed a capacitive ionic sensor array called "FootBeat" that attaches to the dorsal foot in a comfortable manner to accurately collect the pulse waveform, which can be analyzed to acquire a heart rate comparable to that obtained from commercial electrocardiography equipment.…”

“…Particularly, more than three groups of sensor arrays can be used to construct three linear ternary equations in the mathematical sense, and the accurate monitoring of human body temperature can be realized by analyzing these linear equations. 78 Despite the deep development of temperature sensors based on organic ionic fluids, due to the durability and accuracy of these sensors, there are still challenges in developing durable temperature-sensing materials that can reversibly adhere to the skin and avoid interference from epidermal secretions.…”

Tissue Adhesive, Conductive, and Injectable Cellulose Hydrogel Ink for On-Skin Direct Writing of Electronics

“…The application of direct writing to sensitive biological tissues requires high levels of flexibility, repetitive deformation due to movement, and low toxicity [ 25 , 26 ]. Hydrogels are useful for satisfying these conditions because of their tissue-like mechanical properties, conductivity, and biocompatibility [ 27 , 28 , 29 ].…”

Laser-Induced Remote Healing of Stretchable Diselenide-Containing Conductive Composites

“…Remote healing of certain components such as intermediate components, cable sheathing, coatings, and seals in the automotive and aerospace industries or their use in high-tech applications is of vital importance to improve their reliability and durability in both mechanical properties and electrical conductivity. − Remote healing could be divided into autonomic and nonautonomic systems, depending on whether the external stimulus is needed or not . In autonomic systems, healing is driven by a pre-embedded healing agent, supramolecular interactions, − or dynamic covalent bonds. − Although it seems that autonomic healing without external intervention is more convenient than using nonautonomic systems to realize remote healing, there are some intrinsic limitations hindering its further applications.…”