Experimental insights into thermal conductivity, electrical conductivity and DSC analysis of surfactant improved TiO2 – water nanofluids

Abstract

This study investigates the isobaric heat capacity, thermal and electrical conductivity variations in water-based nanofluid containing titanium dioxide nanoparticles, with particular emphasis on the role of surfactants and temperature. While the addition of nanoparticles to distilled water is known to modify its thermophysical properties, the extent of these changes and their underlying mechanisms remain strongly dependent on nanoparticle concentration and the presence or absence of surfactants. In this work, samples were prepared using methods to minimize foaming and were characterized in terms of isobaric heat capacity, thermal conductivity, pH, and electrical conductivity. The isobaric heat capacity of the nanofluid alters with increasing surfactant concentration, a phenomenon primarily driven by micelle formation; however, particle–fluid interactions may partially offset this variation. Thermal conductivity enhancement is primarily attributed to nanoparticle addition, as well as Brownian motion.In contrast, electrical conductivity is dominated by ionic effects, with the presence of surfactants significantly altering nanofluid behavior. Surfactants play a dual role: they stabilize suspensions and prevent agglomeration—thereby enhancing effective heat transfer pathways—yet excessive surfactant concentrations can diminish overall nanofluid performance. Additionally, temperature was found to be a critical parameter influencing all evaluated thermophysical properties. In conclusion, this work demonstrates that properties modification in TiO 2 nanofluids is governed by a complex interplay of factors. These findings extend our team's previous research on surfactant-improved nanofluids and contribute to a broader reference framework for understanding the influence of dispersants on nanofluid performance.