Thermophysical & photothermal characteristics of surfactant free graphene oxide, functionalized graphene oxide and reduced graphene oxide nanofluids

Graphene nanostructures-based dispersions, owing to their improved thermophysical and optical characteristics are being actively explored for use in thermal energy conversion and management. Here, thermophysical and photothermal characteristics of graphene oxide (GO), functionalized graphene oxide (f-GO), and reduced graphene oxide (rGO) based nanofluids (without surfactants) of various concentrations (0.05–0.23 wt.%) are evaluated. The structural, morphology and stability of the nanofluids are determined by XRD analysis, Transmission electron microscopy, UV- visible spectroscopy and zeta potential analysis. Subsequently, thermal conductivity and contact angle measurements are performed. Photothermal behaviour is investigated experimentally. Overall, it is found that among the prepared nanofluids, the f-GO nanofluids performed better compared to GO and rGO nanofluids. Maximum stability of f-GO nanofluids is obtained at 0.05 wt.% while the thermal conductivity and photothermal response is best obtained at 0.23 wt.% concentration.