Recent advances in liquid-metal-based wearable electronics and materials

Phillip Won,Seongmin Jeong,Carmel Majidi,Seung Hwan Ko

doi:10.1016/j.isci.2021.102698

Phillip Won, Seongmin Jeong + Show 2 more

Open Access

https://doi.org/10.1016/j.isci.2021.102698

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Journal: iScience	Publication Date: Jun 9, 2021
Citations: 58	License type: cc-by

Affiliation: Carnegie Mellon University, Seoul National University

Abstract

SummarySoft wearable electronics are rapidly developing through exploration of new materials, fabrication approaches, and design concepts. Although there have been many efforts for decades, a resurgence of interest in liquid metals (LMs) for sensing and wiring functional properties of materials in soft wearable electronics has brought great advances in wearable electronics and materials. Various forms of LMs enable many routes to fabricate flexible and stretchable sensors, circuits, and functional wearables with many desirable properties. This review article presents a systematic overview of recent progresses in LM-enabled wearable electronics that have been achieved through material innovations and the discovery of new fabrication approaches and design architectures. We also present applications of wearable LM technologies for physiological sensing, activity tracking, and energy harvesting. Finally, we discuss a perspective on future opportunities and challenges for wearable LM electronics as this field continues to grow.

Highlights

Stretchable wearable electronics have recently gathered significant interests to a wide range of fields owing to many findings of such electronic wearables proven to provide advantageous features for displays, healthcare monitoring, and other convenient capabilities from well-matched mechanical compliance and portability to the human body
The introduction of eutectic gallium indium (EGaIn) or other gallium-based liquid metal (LM) alloys, which exist as liquids at room temperature (
Initial attempt to use LM in wireless wearable electronics is proposed by Alberto et al to demonstrate an electronic tattoo that has functionalities such as battery-free wireless energy harvesting from passive antenna to monitor electrophysiological monitoring (Figure 8A) (Alberto et al, 2020). This tattoo pattern is printed on a tattoo paper from a desk top printer by loading the Ag flakes ink, and it is sintered by EGaIn LM alloy, making it highly conductive and stretchable

Summary

INTRODUCTION

Stretchable wearable electronics have recently gathered significant interests to a wide range of fields owing to many findings of such electronic wearables proven to provide advantageous features for displays, healthcare monitoring, and other convenient capabilities from well-matched mechanical compliance and portability to the human body. Many recent progresses suggest that three-dimensional architecture in biphasic form can offer higher mechanical stretchability and electrical conductivity and the other interesting properties (Ford et al, 2020; Liu et al, 2021; Lopes et al, 2021) Such approach incorporates suspended or precipitated heterogeneous metallic or nonmetallic materials where LM acts as a solvent or percolating interconnect. There are many interesting versatile properties of these new approaches that could further be explored for LM-based stretchable and wearable electronics (de Castro et al, 2017; Kamysbayev et al, 2019; Tang et al, 2017; Wang et al, 2021; Wang et al, 2018)

Circuits Circuits

EGaIn matrix

Findings

CONCLUSION AND OUTLOOK