Published in Journal of Colloid and Interface Science

The study on “Improvement of thermal conductivity in nanoparticle-dispersed fluids (nanofluids) and elucidation of its mechanism” by Shunsuke Hashimoto et al. in collaboration with J-PARC and CROSS was published in Journal of Colloid and Interface Science.

The dispersion of nanoparticles in liquids has been investigated as a promising method for improving the thermal conductivity of the liquids. Dispersing nanoparticles in a base liquid increases the liquid’s thermal conductivity beyond the theoretical value depending on the particle concentration. However, the underlying mechanism of this enhancement is not fully understood. This study conducted quasi-elastic and small-angle neutron scattering, wide-angle X-ray scattering, and Raman spectroscopic analyses to investigate the translational, rotational, and vibrational motions of liquid molecules around particles in nanofluids. For the first time, the results revealed that the contribution of the previously assumed key factor affecting thermal conductivity, namely the thermal resistance at the solid–liquid interface, is small. Instead, the presence of nanoparticles leads to the changes in the vibrational states of the surrounding liquid molecules, causing them to behave like solid and thereby improving thermal conductivity. These results are highly relevant for the technologies targeting the enhancement of heat transfer in coolants for electric vehicles and fuel cells.

Title: Anomalous Behavior of Liquid Molecules Near Solid Nanoparticles: Novel Interpretation on Thermal Conductivity Enhancement in Nanofluids
Authors: Hashimoto, S., Yamaguchi, S., Harada, M., Nakajima, K., Kikuchi, T., Ohishi, K.
Journal Name: Journal of Colloid and Interface Science
Published: February 3, 2023
https://doi.org/10.1016/j.jcis.2023.01.101