High-performance and frost-resistance MXene co-ionic liquid conductive hydrogel printed by electrohydrodynamic for flexible strain sensor

Yu Wan; Libing Zhang; Ting Wu; Chengli Tang; Haijun Song; Qianqian Cao

doi:10.1016/j.jcis.2024.05.039

High-performance and frost-resistance MXene co-ionic liquid conductive hydrogel printed by electrohydrodynamic for flexible strain sensor

J Colloid Interface Sci. 2024 May 8:669:688-698. doi: 10.1016/j.jcis.2024.05.039. Online ahead of print.

Authors

Yu Wan¹, Libing Zhang², Ting Wu³, Chengli Tang⁴, Haijun Song⁴, Qianqian Cao⁴

Affiliations

¹ School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
² College of Information Science and Engineering, Jiaxing University, Jiaxing 314001, China. Electronic address: libinzhan@zjxu.edu.cn.
³ College of Information Science and Engineering, Jiaxing University, Jiaxing 314001, China. Electronic address: wuting628@zjxu.edu.cn.
⁴ College of Information Science and Engineering, Jiaxing University, Jiaxing 314001, China.

PMID: 38733880
DOI: 10.1016/j.jcis.2024.05.039

Abstract

Conductive hydrogels with high performance and frost resistance are essential for flexible electronics, electronic skin, and soft robots. Nonetheless, the preparation of hydrogel-based flexible strain sensors with rapid response, wide strain detection range, and high sensitivity remains a considerable challenge. Furthermore, the inevitable freezing and evaporation of water in sub-zero temperatures and dry environments lead to the loss of flexibility and conductivity in hydrogels, which seriously limits their practical application. In this work, ionic liquids (ILs) and MXene are introduced into gelatin/polyacrylamide (PAM) precursor solution, and a PAM/gelatin/ILs/MXene/glycerol (PGIMG) hydrogel-based flexible strain sensor with MXene co-ILs ion-electron composite conductive network is prepared by combining the electrohydrodynamic (EHD) printing method and in-situ photopolymerization. The introduction of ILs provides an ionic conductive channel for the hydrogel. The introduction of MXene nanosheets forms an interpenetrating network with gelatin and PAM, which not only provides a conductive channel, but also improves the mechanical and sensing properties of the hydrogel-based flexible strain sensor. The prepared PGIMG hydrogel with the MXene co-ILs ion-electron composite conductive network demonstrates a tensile strength of 0.21 MPa at 602.82 % strain, the conductivity of 1.636 × 10^-3 S/cm, high sensitivity (Gauge Factor, GF = 4.17), a wide strain detection range (1-600 %), and the response/recovery times (73 ms and 74 ms). In addition, glycerol endows the hydrogel with excellent freezing (-60 °C) and water retention properties. The application of the hydrogel-based flexible strain sensor in the field of human motion detection and information transmission shows the great potential of wearable devices, electronic skin, and information encryption transmission.

Keywords: Electrohydrodynamic; Flexible strain sensor; Frost resistance; Hydrogel; Ionic liquid; MXene.