02540nas a2200253 4500008004100000022001400041245013000055210006900185260000800254490000800262520161400270653001101884653001301895653001601908653001101924653001101935653001101946653002301957653010301980653003002083100002102113700002502134856012702159 2017 eng d a0021-979700aStudies on the role of unsaturation in the fatty acid surfactant molecule on the thermal conductivity of magnetite nanofluids0 aStudies on the role of unsaturation in the fatty acid surfactant cNOV0 v5063 a

To study the role of unsaturation in the surfactant molecule on the thermal conductivity of magnetite nanofluids, four different fatty acid (stearic, oleic, linoleic, and linolenic acids with different degree of unsaturation) coated magnetite nanoparticles of comparable size are prepared and dispersed in toluene. It is found that the nanofluid with the saturated fatty acid coated nanoparticles show larger viscosity than the fluid with the unsaturated fatty acid coated particles at all concentrations. Thermal conductivity studies show enhancement only above a critical concentration for all fluids. The critical concentration for thermal conductivity enhancement varies with the surfactant, possibly due to the difference in the degree of aggregation of the nanoparticles in the fluid, because of the difference in the conformation of the surfactant molecules on the nanoparticle's surface. The experimental thermal conductivity follows the Maxwell model at higher concentrations. From the overall studies, it is observed that the thermal conductivity of the fluids with aggregated or assembled nanoparticles shows slightly larger enhancement than that of the fluids with isolated particles. However, in the presence of a magnetic field, the fluids with isolated nanoparticles showed relatively larger enhancement, possibly due to the easy response of the isolated magnetite nanoparticles to the applied field. (C) 2017 Elsevier Inc. All rights reserved.

10aChains10aDynamics10aEnhancement10aFields10aFluids10aForces10agold nanoparticles10aMagnetic fluid; Nanofluid; Surfactant; Unsaturation; Conformation; Thermal conductivity; Viscosity10aSelf-assembled Monolayers1 aLenin, Ramanujam1 aJoy, Pattayil, Alias uhttps://library.ncl.res.in/content/studies-role-unsaturation-fatty-acid-surfactant-molecule-thermal-conductivity-magnetite