Graphene-Based Flexible and Eco-Friendly Wearable Electronics and Humidity Sensors

A novel, efficient, and cost-effective coating method was developed for fabricating highly conductive cotton yarn loaded with reduced graphene oxide (rGO). This method is straightforward, rapid, scalable, and amenable to solution processing. The key innovation involves pretreating the cotton yarn with chicken egg albumin (CEA) before applying the rGO coating through a simple dip-and-dry process. This method significantly reduces the electrical resistance of the cotton yarn, achieving an optimal specific resistance of 80 Ω.g/cm² with just five coating cycles. Additionally, the coated samples exhibit exceptional reliability, enduring 10⁴ bending tests and 5 washing tests without compromising conductivity. Notably, the study reveals consistent proportional variations in response to changes in relative humidity, regardless of the initial reference resistance value or yarn characteristics. These stable and conductive rGO-coated cotton yarns (rGOCY) might be seamlessly integrated into textiles and garments, enabling the development of flexible and wearable electronics, as well as sensors.

Keywords:
Cotton yarn flexible sensors; chicken egg albumen; dip and dry coating; reduced graphene oxide; humidity sensor