Multifunctional and stretchable graphene/textile composite sensor for human motion monitoring

Abstract

Sensors based on electronic textiles (e‐textiles) have become increasingly prominent in the field of biomechanical monitoring technology due to multiple properties such as being lightweight, flexible, and comfortable, with increasing potential in incorporating into long‐term monitoring devices. Previous research has been conducted into textile strain sensors based on graphene for human motion monitoring, however most graphene e‐textile strain sensors exhibit poor sensitivity and stretchability. To our knowledge, no previous research has looked at knitted graphene‐based fabrics in regards to the fabric composition of the substrate. In this paper, we propose a graphene/fabric composite sensor using a cost‐effective dip coating method of an acrylic/Spandex knit fabric, and further explores its mechanical, electrical, and sensing properties. The developed graphene/textile composite sensor has a wide sensing range (up to 344%) and exhibits a good sensitivity with a high gauge factor of up to 16. As a wearable sensor, our sensing fabric can detect both large and subtle human motions and is able to distinguish between various ranges of joint movements, demonstrating its ability to function as a human motion monitoring system. Our sensor further exhibits the ability to be used as a supercapacitor or capacitive pressure sensor.

Graphene‐Based Textiles for Thermal Management and Flame Retardancy

“…Zhou et al. [ 44 ] have reported an increased ultimate stress increases with the GNP concentration in GNP coated fabrics, which increases from ≈0.09 MPa for control sample to 0.18 MPa at 1.5 wt.% GNP concentration. This is thought to be due to the deposited GNPs that offers rigid chemical bonding.…”

Highly flexible, durable, UV resistant, and electrically conductive graphene based TPU/textile composite sensor

“…To optimize the stability and stretchability of the fabrics, we designed these fabrics using our published method. 26 To briefly explain, a gauge 10 double bed knitting machine with a stitch tension of 9 was chosen as the optimal setting for knitting acrylic/Spandex yarns into fabrics to reduce processing faults and maintain good knitting quality. A full needle knitting structure was selected to enhance the stretchability of the fabrics.…”

“…There are many functional textile sensors that have been developed based on graphene using various techniques, but most of the reported textile strain sensors have difficulty maintaining a high sensitivity over a large monitoring range in wearable applications 11,17 . This is potentially due to the structure of the selected textiles limiting the stretch and recovery capabilities of the sensor 26 . When graphene‐based sensors are fabricated with woven fabrics, they generally exhibit dimensional stability, but exhibit limited elastic recovery during human motions, making it difficult to adapt to the human body 27–29 .…”

“…11,17 This is potentially due to the structure of the selected textiles limiting the stretch and recovery capabilities of the sensor. 26 When graphenebased sensors are fabricated with woven fabrics, they generally exhibit dimensional stability, but exhibit limited elastic recovery during human motions, making it difficult to adapt to the human body. [27][28][29] Knitted structures are more suitable in creating flexible structures which closely fit the human body without restricting motions and therefore are more suitable as strain sensor applications for collecting data close to the body with the integration method remaining hidden.…”

“…37 In our previous study, we examined the effect of yarn composition within a textile strain sensor, selecting the yarns with the best stretchability and recovery to design fabrics for strain sensors. 26 In this study, we propose a fast, convenient, and scalable manufacturing approach to fabricate highly sensitive and stretchable graphene-based TPU/knitted textile strain sensors. The graphene-based sensing fabric is designed and knitted in both wale and course directions of knitting structures and fabricated into composite sensors using laser cutting combined with film coating and a thermal transfer process.…”