Moisture-Resilient Graphene-Dyed Wool Fabric for Strain Sensing

Abstract

E-textile consisting of natural fabrics has become a promising material to construct wearable sensors due to its comfortability and breathability on the human body. However, the reported fabric-based e-textile materials, such as graphene-treated cotton, silk, and flax, generally suffer from the electrical and mechanical instability in long-term wearing. In particular, fabrics on the human body have to endure heat variation, moisture evaporation from metabolic activities, and even the immersion with body sweat. To face the above challenges, here we report a wool-knitted fabric sensor treated with graphene oxide (GO) dyeing followed by l-ascorbic acid (l-AA) reduction (rGO). This rGO-based strain sensor is highly stretchable, washable, and durable with rapid sensing response. It exhibits excellent linearity with more than 20% elongation and, most importantly, withstand moisture from 30 to 90% (or even immersed with water) and still maintains good electrical and mechanical properties. We further demonstrate that, by integrating this proposed material with the near-field communication (NFC) system, a batteryless, wireless wearable body movement sensor can be constructed. This material can find wide use in smart garment applications.

Graphene-Incorporated Natural Fiber Polymer Composites: A First Overview

“…Many works have reported the effect on the mechanical [ 50 , 53 , 65 , 71 , 72 , 108 , 109 , 110 , 111 , 112 , 113 , 115 ], thermal [ 51 , 53 , 65 , 100 , 115 ] and electrical [ 50 , 52 , 115 , 116 ] properties of fiber composites reinforced with graphene-based materials. A detailed discussion of NLFs-GO/polymer matrix composites properties can be found in Section 4 .…”

“…However, the materials commonly used to produce them, such as silver and copper, are expensive, nonbiodegradable, and toxic [ 175 ]. Hence, new solutions for environmentally friendly e-textiles have been explored over the last years [ 115 , 171 , 172 , 175 , 176 , 177 , 178 ]. Among these studies, the e-textiles coated with graphene-based materials have already shown great promise [ 172 , 175 , 176 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 ].…”

“…Natural fibers, such as cotton [ 172 , 175 , 176 , 184 , 185 ], silk [ 177 ], flax [ 178 ], and wool [ 115 ] in woven and knitted structures coated with graphene-based materials [ 186 , 187 ] have been investigated as e-textiles. Ren et al [ 176 ] proposed a flexible conductive cotton fabric coated with GO by vacuum filtration followed by a hot press method to its reduction (rGO).…”

“…According to Xu et al [ 115 ], the wearable e-textiles of natural fibers (cotton, silk, flax) coated with graphene-based materials that have been reported until now [ 172 , 175 , 177 , 178 ] may present long-term electrical and mechanical instability due to the temperature variations and moisture from metabolic activities of the human body. Therefore, they proposed a wearable sensor of wool-knitted fabric coated with GO followed by the L-ascorbic acid reduction process, which was capable to keep good electrical and mechanical properties with moisture up to 90% [ 115 ]. The authors indicated that, after 10 washing cycles, the sheet resistance of ~2 kΩ/sq exhibited by the wool/rGO conductive textile was higher than the compressed and encapsulated graphene-based cotton e-textile (< 1 kΩ/sq) reported in the work of Afroj et al [ 41 ].…”

Smart textiles and wearable technologies – opportunities offered in the fight against pandemics in relation to current COVID-19 state

“…Having all the challenges in the head of us the optimal outcome is to emerge from the current crisis with a clearer vision of how to deploy telemedicine to achieve its benefits while avoiding or minimizing potential abuse and exploitation [147]. Smart or e-textiles start to include natural fabrics and become sensors of human body temperature, sweat, or breathing [155] or bending able to monitor human touch [156]. As the strain sensors can be incorporated in smart garment parts, it can be a part of face masks too, together with other biosensing capabilities for detecting viruses.…”