Effect of interfacial layer around core-shell nanoparticles on thermal conductivity of nanofluids

Core-shell nanoparticles are a special type of nanostructured materials characterized by excellent dispersion in nanofluids due to surface modification. In this work, we investigate the thermal conductivity of nanofluid considering different surface materials and core-shell ratios. It has been found by molecular dynamics simulations that the thermal conductivity of core-shell nanofluids can be significantly enhanced compared to that of ordinary nanofluids. The nanofluid with Cu@Au particles has a better thermal enhancement than the Cu@Ag nanofluid. The thermal conductivity of core-shell nanofluid exhibits a non-monotonic variation with increasing core-shell ratio, which cannot be explained by classical Maxwell model. Based on the analysis of phonon state density, it is found that higher thermal conductivity is consistent with more match degree of phonon coupling at the interface. The findings in the present paper have important implications for the design of nanofluids with better thermal properties..