Application of UV/Vis spectroscopy to assess the stability of oil-based nanofluids

Oil-based nanofluids were investigated as a potential substitution for conventional oil. The major challenge that faces the practical application of oil-based nanofluids is the suspension stability of nanoparticles. Missing suspension stability will negatively affect dielectric properties of nanofluids. So, the main objective in this study is to investigate the suspension stability of oil-based nanofluids using UV/Vis spectroscopy. The effect of weight fraction and surface treatment of nanoparticles on the stability is evaluated. The study was performed using TiO
₂
nanoparticles with an average particle size of 20 nm. Two sets of samples were prepared without and with surface treatment of nanoparticles. For each set, different weight fractions of nanoparticles have been used. UV/Vis spectroscopy was used to monitor the stability of nanofluids through observing the maximum absorbance and the corresponding wavelength for each sample. The stability was assessed through evaluating the decrement in absorbance after 24 hours from preparation. After investigating the stability of prepared samples, dielectric strength has been evaluated and compared for all samples.