Highly Stretchable, Elastic, and Sensitive MXene-Based Hydrogel for Flexible Strain and Pressure Sensors.

Yao Lu,Xiaochen Dong,Qian Wang,Wenjun Wang,Weili Si,Wen Zhao,Wei Huang,Yanfang Ren,Xinyu Qu

doi:10.34133/2020/2038560

Abstract

Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition. However, it remains a challenge to fulfill the requirements on detecting full-range human activities with existing flexible strain sensors. Herein, highly stretchable, sensitive, and multifunctional flexible strain sensors based on MXene- (Ti3C2Tx-) composited poly(vinyl alcohol)/polyvinyl pyrrolidone double-network hydrogels were prepared. The uniformly distributed hydrophilic MXene nanosheets formed a three-dimensional conductive network throughout the hydrogel, endowing the flexible sensor with high sensitivity. The strong interaction between the double-network hydrogel matrix and MXene greatly improved the mechanical properties of the hydrogels. The resulting nanocomposited hydrogels featured great tensile performance (2400%), toughness, and resilience. Particularly, the as-prepared flexible pressure sensor revealed ultrahigh sensitivity (10.75 kPa−1) with a wide response range (0-61.5 kPa), fast response (33.5 ms), and low limit of detection (0.87 Pa). Moreover, the hydrogel-based flexible sensors, with high sensitivity and durability, could be employed to monitor full-range human motions and assembled into some aligned devices for subtle pressure detection, providing enormous potential in facial expression and phonation recognition, handwriting verification, healthy diagnosis, and wearable electronics.

Highlights

In recent years, electronic skins (E-skins) have attracted extensive interests due to their similar functions to the human skin, including stretchability, multifunctional sensing capabilities, and wide sensing range [1]
The MXenecomposited hydrogel was prepared by incorporating MXene nanosheets into a polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) double-network hydrogel system
MXene-composited double-network hydrogels with excellent mechanical performances and conductivity have been successfully constructed by integrating MXene into PVA/PVP hydrogels

Summary

Introduction

Electronic skins (E-skins) have attracted extensive interests due to their similar functions to the human skin, including stretchability, multifunctional sensing capabilities, and wide sensing range [1]. With limited degree of crosslinking and high viscosity, single-network hydrogels exhibit poor mechanical property and stability [8, 9]. This problem can be effectively alleviated by introducing effective energy dissipation domains or constructing a double-network hydrogel [10,11,12]. It is still challenging to combine good mechanical property with high sensing performance to design a highly stretchable and sensitive strain sensing hydrogel for wearable electronics.

Methods

Results

Conclusion