Facile synthesis of CuO nanospindles from a 3D coordination complex and its application to nanofluids

• CuO nanospindles from a 3D coordination complex.
• The smaller size, simple and economical method of preparation.
• Size uniformity and appropriate dispersion.
• No residual impurities.
• Enhanced thermal conductivity of CuO/ethylene glycol nanofluids.

This paper reports a facile and residue free synthesis of copper oxide (CuO) nanospindles by the thermal decomposition of a 3D precursor complex, copper benzoate dihydrazinate at 100 °C. Transmission electron microscopy revealed monodispersed nanospindles with a mean diameter of approximately 22 nm. X-ray diffraction and selected-area electron diffraction showed that the nanospindles were composed of a pure monoclinic phase of polycrystalline CuO. The nanospindles were also confirmed by Raman spectroscopy. The enhancement of the thermal conductivity of ethylene glycol (EG) in the presence of CuO nanospindles was examined. No surfactant was used as a dispersant. The volume fraction of CuO nanospindles suspended in EG was less than 5 vol%. The thermal conductivity of the CuO nanofluids increased with increasing particle loading.