Application of self-heating graphene reinforced polyvinyl alcohol nanowires to high-sensitivity humidity detection

In this study, we measured the performance of self-heating conductive conjugated polyvinyl alcohol, (PVA)/graphene (G) composite nanofibers in the detection of environmental humidity. PVA-G polymer nanocomposite fibers were electrospun together from suspensions of PVA and varying concentrations of pristine G sheets. The extent of graphene dispersion in the nanocomposite fibers were characterized via Raman and transmission electron microscopy (TEM) analysis. Where the main content of C and O elements in composite nanofibers were obtained from the energy dispersive (EDX) spectra and EDX mapping results. Thermal characteristics and structural morphology were then investigated through thermal gravimetric analysis (TGA), and focused ion beam scanning electron microscopy (FIB-SEM) & laser scanning confocal microscopy (LSCM), respectively. Applied voltages (0−10 V) to the PVA-G polymer nanocomposite fibers under varying conditions of humidity were investigated. With increasing concentration of G, increased sensitivity to relative humidity could be observed through the proportional changes in resistance. In addition, at PVA-G concentrations at 6%, the tested humidity sensor remained highly responsive while operating at low temperatures of 60 °C and with minimal power consumption.