Surfactant–assisted synthesis and characterization of copper oxide (CuO) nanostructures

Abstract This study aims to investigate the role of a non-ionic surfactant in controlling the growth, morphology, and structural properties of copper oxide (CuO) nanostructures synthesized via a sol–gel route. CuO nanoparticles were prepared using aqueous copper sulfate as the precursor and Tween 80 as a structure-directing and stabilizing agent, with systematic control of synthesis parameters followed by calcination to obtain crystalline products. The as-synthesized materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to evaluate phase formation, chemical interactions, thermal stability, and surface morphology. The results confirm the formation of phase-pure monoclinic CuO with nanoscale crystallite sizes, as evidenced by sharp XRD reflections and Scherrer analysis. SEM observations reveal that Tween 80 effectively suppresses excessive agglomeration and promotes the formation of relatively uniform nanostructures with mixed spherical and polyhedral morphologies. FTIR and TGA analyses further demonstrate the presence of surfactant–nanoparticle interactions during synthesis and their complete removal upon calcination, resulting in thermally stable CuO nanostructures. Overall, the study demonstrates that Tween 80 plays a crucial role in regulating nucleation and growth processes, offering a straightforward and cost-effective approach for tailoring CuO nanostructures through surfactant-assisted sol–gel synthesis.