Influence of amphoteric and anionic surfactants on stability, surface tension, and thermal conductivity of Al2O3/water nanofluids

Abstract

The influence of surfactants on the dispersion, stability, and thermophysical characteristics of 0.5%-alumina/distilled water nanofluid was investigated. The study was conducted for a range of surfactant blending ratios (0.5, 1.0, and 1.5 wt%) with an amphoteric (LB) or anionic surfactant (SDS or SDBS). The results revealed that the nanofluids have different dispersion, stability, and thermophysical characteristics depending on the type of surfactant and the blending ratio. The amphoteric surfactant exhibited lower absorbance than the anionic surfactants did across a wavelength range of 650–1050 nm and rendered made the alumina nanofluid more unstable. The value of absolute zeta potential when using the anionic surfactants was higher than that of pure alumina nanofluid. The thermal conductivity of the alumina nanofluid with the amphoteric surfactant was higher than that with the anionic surfactants, although all the surfactants reduced the thermal conductivity of the 0.5 wt% alumina nanofluid at 293.15 K. However, regarding surface tension, there were no notable changes in the alumina nanofluids depending on the type of surfactant. Because surfactants have a significant effect on the properties of alumina nanofluids, this study provides a foundation for future applications of such mixtures in a variety of fields.

Keywords

• Nanofluids
• Al2O3
• Surfactant
• Stability
• Surface tension
• Thermal conductivity