Surface and optical properties of ethylene glycol-based nanofluids containing silicon dioxide nanoparticles: an experimental study

In this paper, the results of the experimental study on density, surface tension and optical properties of ethylene glycol-based nanofluids containing silicon dioxide have been presented. The nanofluid-air surface tension values were determined in the temperature range from 283.15 K to 318.15 K with Du Noüy ring method with the commercial equipment and self-made station. To determine the surface tension of a fluid, the information about its density is required; therefore, density of all examined nanofluids was measured in the same temperature range, and results were summarized in the paper. The refractive index of SiO2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}-EG nanofluids was determined in the same temperature range in which the surface tension was examined. Finally, the extinction (UV–Vis spectra) of these materials was examined and presented.