Highly Stretchable and Kirigami-Structured Strain Sensors with Long Silver Nanowires of High Aspect Ratio

Huiyan Huang,Bok Seng Yeow,Jianyong Ouyang,Catherine Jiayi Cai,Hongliang Ren

doi:10.3390/machines9090186

Abstract

Stretchable, skin-interfaced, and wearable strain sensors have risen in recent years due to their wide-ranging potential applications in health-monitoring devices, human motion detection, and soft robots. High aspect ratio (AR) silver nanowires (AgNWs) have shown great potential in the flexible and stretchable strain sensors due to the high conductivity and flexibility of AgNW conductive networks. Hence, this work aims to fabricate highly stretchable, sensitive, and linear kirigami strain sensors with high AR AgNWs. The AgNW synthesis parameters and process windows have been identified by Taguchi’s design of experiment and analysis. Long AgNWs with a high AR of 1556 have been grown at optimized synthesis parameters using the one-pot modified polyol method. Kirigami sensors were fabricated via full encapsulation of AgNWs with Ecoflex silicon rubber. Kirigami-patterned strain sensors with long AgNWs show high stretchability, moderate sensitivity, excellent linearity (R2 = 0.99) up to 70% strain and can promptly detect finger movement without obvious hysteresis.

Highlights

Stretchable and wearable strain sensors have grown to prominence in recent years due to their wide potential applications in flexible electronics, rehabilitation and personal healthmonitoring devices, human motion detection, and soft robots [1,2]
Stretchability, sensitivity, and linearity are crucial for wearable strain sensors while ensuring excellent skin conformation for in situ health monitoring [3]
Due to the wide variation of the synthesis parameters, the samples vary from Ag nanoparticles (L = 0) to AgNWs with D = 28.7–97.3 nm and L = 10.7–29.5 μm

Summary

Introduction

Stretchable and wearable strain sensors have grown to prominence in recent years due to their wide potential applications in flexible electronics, rehabilitation and personal healthmonitoring devices, human motion detection, and soft robots [1,2]. Despite these sensors showing great promise in future health monitoring, more studies are needed to create a customizable yet scalable fabrication approach to improve the sensing properties. Graphene on flexible substrates has been used to fabricate high-sensitivity strain sensors [4,5] These carbon-based strain sensors show low stretchability, non-linearity, and high hysteresis

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