Layer-by-layer assembly of graphene oxide on viscose fibers for the fabrication of flexible conductive devices

Flexible conductive devices were successfully fabricated through the layer-by- layer assembly of graphene oxide on the surface of viscose fibers followed by the reduction of graphene oxide to graphene. Viscose fibers with regions of low crystallinity played an important role in the distribution of reduced graphene oxide on the fiber surfaces. Scanning electron microscopy results demonstrated that graphene oxide could form uniform coatings with fewer cycles (<12), but exhibits the coating peeling or faulting over a greater number of cycles (>30). Owing to the presence of conductive coatings, the average volume resistivity value of the fabrics with fifty cycles could reach 33.31 Ω cm in the weft direction and 19.17 Ω cm in the warp direction, in contrast to the original fabric, which showed very little conductivity. Meanwhile, electrical resistivity tests of the fabrics under stretching and folding showed that minor changes in volume resistivity were observed when the change in the elongation rate of the fabrics was in the 0–15 % range and the folding angle of the fabrics was between 0° and 180°. Furthermore, such viscose fabrics with reduced graphene oxide layers showed improved hydrophobicity. For the fabric treated for five cycles, a water contact angle of 133.3° was achieved. The assembly of graphene oxide on the surface of viscose fibers provides an easy approach for the fabrication of flexible conductive devices with potential applications in solar cells, seawater desalination, wearable electronics, etc.