Experimental study on SDBS surfactant effect on titanium oxide water nanofluid properties

The thermal performance of heat transfer fluids can be enhanced by dispersing solid particles in conventional base fluids. In this context, nanofluids—obtained by suspending nanoparticles at low concentrations in a base fluid such as water—have attracted considerable attention as advanced heat transfer media. In the present study, water-based titania (TiO₂) nanofluids were investigated as potential heat transfer fluids. The main objective of this experimental work is to examine the influence of different concentrations of the surfactant sodium dodecylbenzenesulfonate (SDBS) on the stability and thermophysical properties of TiO₂ nanofluids. Specifically, the effects of surfactant addition on density, viscosity, and thermal conductivity were experimentally measured and analyzed over a range of temperatures. To achieve this objective, eleven water-based nanofluid samples containing 2 wt% TiO₂ were prepared using the two-step method. The results showed that the addition of SDBS significantly improved the dispersion stability of the nanoparticles; however, it also led to excessive foam formation, particularly at higher surfactant concentrations. From a thermophysical standpoint, the presence of SDBS caused a reduction in thermal conductivity, while both density and viscosity were found to increase compared to the surfactant-free nanofluid. These findings highlight the trade-off between improved stability and altered heat transfer properties when using surfactants in nanofluid formulations and substantiate the relevance of calculating carefully the surfactant quantity.