Dispersion stability and surface tension of SDS-Stabilized saline nanofluids with graphene nanoplatelets.

• SDS stabilizer and ultrasonication gives better dispersion of GNP in Saline media. • The surface tension of GNP-Saline nanofluids decreases with temperature. • A maximum decrease of 21 % in surface tension is found by adding GNP is saline media. • Increase in GNP wt% (0.05 - 0.25) in nanofluid have no impact on surface tension. The dispersions of engineered nanomaterials in fluids have envisioned numerous industrial applications. Despite less experimental data available on the surface tension of nanofluids, it is one of the critical parameters to define thermal configurations and two-phase transport properties. This study focuses on the benchmark experimental investigation of the surface tension behavior in graphene nanoplatelets-based saline nanofluids in ambient air using the pendant drop method. Graphene nanoplatelets are dispersed in saline fluid (30PPT) using optimum anionic SDS stabilizer and ultrasonication, exhibiting excellent stability for minimum 72 h. Different characterizations are performed for nanoplatelets and nanofluid stability such as electron microscopy, FTIR, XRD, DLS and sedimentation analysis. Surface tension measurements are taken at varying concentrations of graphene nanoplatelets range of 0-0.25 wt% and temperature range of 25−65 °C. The obtained results from this research exhibit that the addition of nanoplatelets drops the surface tension of saline fluid by 21 %. However, the increase in concentration from 0.05 wt% to 0.25 wt% does not have a considerable implication on the overall surface tension behavior. It is observed that the surface tension of the saline fluid and the nanofluid decrease with the elevation in temperature. [ABSTRACT FROM AUTHOR]