EG-Assisted hand-in-hand growth of prism-like Cu₂O nanorods with high aspect ratios and their thermal conductive performance

In this work, one-dimensional, monodispersed prism-like Cu₂O nanorods with a significantly high aspect ratio (∼100) have been successfully prepared by a simple hydrothermal synthesis with the assistance of ethylene glycol (EG). The obtained nanorods expose {100} faces and have a rectangular cross section. Their length, thickness and width are in the range of 50-100 μm, 0.5-1 μm and 0.5-1.5 μm, respectively. Pyrrole (Py) and EG play important roles in the formation of the prism-like nanorods. Py acts as a structure-directing reagent that makes the Cu₂O crystal grow along the [100] direction. EG acts as a "bridge" that controls the "hand-in-hand" growth of the intermediate Cu₂O nanowires and transforms them into prism-like nanorods. The products are first employed as thermal conductive nanofillers to improve the thermal conductivity of poly(vinylidene fluoride) (PVDF)-based polymer composites. The original thermal conductivity studies indicate that the rod-type structural nanomaterials are very efficient fillers for polymer composites. When they were embedded in the PVDF matrix at 30 wt%, the Cu₂O nanorods show a thermal conductivity enhancement (TCE) of 275% when compared with the pristine PVDF, which is 1.4 times higher than commercial Cu₂O (cubes) used as fillers in PVDF composites.