Investigations on the optical, dielectric, electrical, and rheological properties of PEG200/ZnO semiconducting nanofluids for soft matter based technological innovations

Abstract

Semiconducting nanofluids (SNFs) consisting of poly (ethylene glycol) (PEG200) as a green biocompatible base fluid with homogeneous dispersion of eco-friendly zinc oxide (ZnO) nanomaterial, concentrations ranging from 0.01 to 0.20 wt%, are prepared by state-of-the-art ultrasonic cavitation homogenized process. These PEG200/ZnO SNFs are characterized by employing an ultraviolet-visible (UV-Vis) spectrophotometer, precision inductance-capacitance-resistance (LCR) meter, and rotational viscometer. A detailed analysis of 200–800 nm range UV–Vis absorbance spectra of these SNFs revealed longer stability of suspended ZnO nanoparticles in PEG200 fluid, and their nanomaterial concentrations dependent absorbance and extinction coefficient with tunable dual energy band gaps ranging from 3 to 5 eV. Optical performance recognized the potential applications of these SNFs in the advances of soft matter based optoelectronic and photosensitive devices and also as an excellent UV radiation shielding material. The study of 20 Hz – 1 MHz range dielectric and electrical spectra explained that the ZnO concentrations have a significant impact on the electrical conductivity of these SNFs, while the dielectric permittivity and electrode polarization relaxation process are marginally altered. High static dielectric permittivity (∼ 22) and low electrical conductivity of about μS/cm order, at 303.15 K, evidence the suitability of these SNFs in advances of energy storage devices. The rheological behaviour of PEG200/ZnO materials is carried out at different temperatures ranging from 303.15 to 323.15 K, which illustrates the Newtonian characteristics of these nanofluids with moderate dynamic viscosity and activation energy, and therefore, they could be utilized as effective heat transfer materials in photovoltaic/thermal devices and systems.