Multifunctional Iontronic Sensor Based on Liquid Metal-Filled Ho llow Ionogel Fibers in Detecting Pressure, Temperature, and Proximity

Abstract

Fiber-based pressure/temperature sensors are highly desired in wearable electronics because of their natural advantages of good breathability and easy integrability. However, it is still a great challenge to fabricate reliable and highly sensitive fiber-based pressure/temperature sensors via a scalable and facile strategy. Herein, a novel fiber-based iontronic sensor with excellent pressure-and temperature-sensing capabilities is designed by assembling two crossed hollow and porous ionogel fibers filled with liquid metal. Serving as a pressure sensor, a high detection resolution (1.16 Pa), a high sensitivity of 13.30 kPa −1 (0−2 kPa), and a wide detection range (∼207 kPa) are realized owing to its novel hierarchical structure and the selection of deformable liquid electrodes. As a temperature sensor, it exhibits a high temperature sensitivity of 25.99% °C−1 (35−40 °C), high resolution of 0.02 °C, and good repeatability and reliability. On the basis of these excellent sensing capabilities, the as-prepared sensor can detect not only pressure signals varied from weak pulse to large joint movements but also the proximity of different objects. Furthermore, a large-area fiber array can be easily woven for acquiring the pressure mapping to intuitively distinguish the location, magnitude, and shape of the loaded object. This work provides a universal strategy to design fiber-shaped iontronic sensors for wearable electronics.

Micropyramidal Flexible Ion Gel Sensor for Multianalyte Discrimination and Strain Compensation

“…Equation 3 exhibits the inverse proportional dependence between the conductivity σ and the viscosity η of ILs. Besides that, the Seddon's equation shows the change in viscosity of ILs after dissolving gases as follows 62 = i k j j j y { z z z a exp s cs (4) where η, η s , χ cs , and a are the viscosity of the pure IL and gasdissolved IL at 20 °C, the mole fraction of the dissolved gas, and the constant for specific IL, respectively. When IL absorbs gas, the dissolved gas molecules prevent ions from interacting, reducing IL viscosity and increasing the number of free ions, as depicted in Figure 1e.…”

“…Flexible electronics have recently fascinated academia and industry due to their emerging applications in health care monitoring, environmental monitoring, Internet-of-Things (IoT), electronic skin, and robotics. − Rapid industrialization and urbanization in recent decades have also given rise to several environmental issues affecting the quality of air that we breathe in and out daily. Air pollution is a critical problem that harms human and animal health as an invisible poison.…”

Flexible and Transparent Electronic Skin Sensor with Sensing Capabilities for Pressure, Temperature, and Humidity

“…Human skin can not only act as a biological barrier to protect the internal tissues and organs but also serve as a multisensory sensor to perceive the outside world, which can detect strain, pressure, shear, temperature, and humidity. − To mimic these versatile sensing capabilities of natural skin, various flexible electronic-skin (e-skin) sensors have been developed to realize individual sensing functions, including strain, pressure, temperature, and humidity sensors. − Basically, the principle of these sensors is to convert external stimuli into electrical signals, such as resistance, − capacitance, − current, − or voltage, − which can be collected and analyzed by a computer. Up to now, most sensors can only realize one single sense function. , Thus, there is a need to integrate different types of sensors together to achieve multisensory sensing capabilities of e-skin as it is desirable for one single sensor to possess different sensing capabilities.…”

Dual-Stimuli-Responsive and Anti-Freezing Conductive Ionic Hydrogels for Smart Wearable Devices and Optical Display Devices

“…Artificially intelligent materials have attracted considerable attention in recent years for their ability to convert monitored macroscopic and subtle changes caused by external forces (and deformations) into electrical signals, − a property that makes them useful in areas such as bionic skins, , wearable electronic devices, and human–computer interaction . Among the various types of conventional conductive materials, ion-conductive hydrogels have emerged as the most promising flexible materials because of their high similarity to natural soft tissues, good mechanical adaptability to organs such as skin and muscles, − good ionic conductivity, , and excellent stretchability. − Currently, research on ion-conductive hydrogels lies in improving their transparency, , electrical sensing sensitivity, anti-freezing properties, − and mechanical properties. − …”