Bioinspired lotus fiber-based graphene electronic textile for gas sensing

Graphene electronic textiles (e-textiles) have attracted significant attention in various sensing applications owing to their strong advantages. During the fabrication of these textiles, there are factors to consider, such as electrical conductivity, mechanical flexibility, weight, and applicability in other practical applications. Bioinspired lotus fiber has appropriate advantages to be used as graphene e-textiles, including lightweight (< 1 mg), eco-friendliness, crease-resistant, pilling resistance, and flexibility. However, lotus fiber-based graphene e-textiles have not yet been reported. In this study, we developed a reduced graphene oxide‒coated lotus fiber (RGOLF) which was successfully fabricated by the hydrogen interaction between graphene flakes and cellulose fiber. The higher the GO concentration (~ 3 g/L) and fiber diameter (~ 300 μm), the higher the electrical conductivity of the RGOLF was measured. The RGOLF exhibited a higher electrical conductivity (4.63 ± 0.22 μS) and a remarkable sensing performance for hazardous NO₂ gas molecules within a short exposure time (~ 3 min), including a low detection limit (~ 1 ppm), selectivity, and resistance to relative humidity. Moreover, we verified the mechanical flexibility and elasticity of RGOLF through a 1,000-cycle bending test, and tensile test, respectively. These results suggest that the bioinspired RGOLF could be used as a gas sensor in environmental air with a strong potential for use in various wearable applications.