Modified-liquid-liquid phase separation: A novel technique to synthesize 2-dimensional CuO nanosheets

The 2-dimensional materials are seeing an upsurge in research and various applications. In this work, the growth of cupric oxide (CuO) nanostructures in different morphologies is reported by employing modified -liquid-liquid phase separation ( m- LLPS) technique. Here, two binary phases copper sulphate-polyethylene glycol (PEG) i.e. C&P and sodium hydroxide-PEG i.e. N&P are used in tandem and reduction of copper salt is employed. Sheet-like agglomerated growth could be restrained into nice flattened disks by merely modifying the interaction of binary phases in time. X-ray diffraction (XRD) for structural information, UV-Visible spectroscopy for optical bandgap estimation, micro-Raman spectroscopy for vibrational levels investigation, and Fourier Transform Infrared spectroscopy (FTIR) as fingerprint for bond/ compound formation have been employed. The flat-disk CuO sample was used for detection of glucose. Limit of detection and limit of quantification levels were estimated and were found to be 4 mM and 13 mM, respectively. The mechanism of the modified -LLPS method leading to oriented growth from disoriented growth is discussed. By taking CuO as an example, a very simple concept of phase separation has been demonstrated to prepare 2-dimensional materials.