Altun, AycanDoruk, SemahatSara, Osman Nuri2026-02-122026-02-1220230195-928X1572-9567https://doi.org/10.1007/s10765-023-03214-1https://hdl.handle.net/20.500.12885/6685In recent years, nanofluids obtained using nanoparticles and ionic liquids as base fluids have been examined under the title ionanofluids. In the present work, density, viscosity, and specific heat of 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIM][EtSO4], and [EMIM][EtSO4]-based ionanofluids prepared with Al2O3 nanoparticles have been measured at atmospheric pressure and from 293.15 K to 343.15 K with a 5 K step increment. It is observed that the experimental results for density, viscosity, and heat capacity of prepared ionanofluids do not match the results obtained from the classical equations used to estimate these properties. A temperature-dependent first-order polynomial is described to estimate the density of nanofluids, while a new relative viscosity model, which is a second-order polynomial including particle ratio parameter, is fitted to experimental viscosity data. Besides, hysteresis loops of the nanofluids have been investigated. The heat capacity values of the nanofluids with volume fractions of 0.16 %, 0.32 %, and 0.96 % Al2O3 are obtained to be higher than those of the pure ionic liquid, whereas the heat capacity values of the nanofluid prepared with 1.62 % and 2.65 % Al2O3 are lower.eninfo:eu-repo/semantics/closedAccessIonanofluidsIonic liquidsNanofluidsNanoparticlesNEILsThermal propertiesArticle10.1007/s10765-023-03214-1447WOS:0009970252000012-s2.0-85160665560Q2Q2