Linear and nonlinear optical characteristics of PVA/CMC/PEG blended polymer loaded with ZnS formed at different temperatures

Abstract

Pure and loaded polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG: 70/15/15%) blends with zinc sulfide (ZnS) were prepared at different temperatures (200, 300, 400, and 500 °C) using solid state reaction at low temperatures and casting procedures. The phases formed, cell parameters, crystallite size, and lattice microstrain parameters of the nanofillers (ZnS at different temperatures) were investigated using the Rietveld method. The obtained polymer blends loaded with ZnS were characterized using X-ray diffraction, Fourier transform infrared, and scanning electron microscope techniques. The impact of loading ZnS on the linear and nonlinear optical parameters of the blended polymers was explored in detail. The optical energy (Eg) values (direct = 5.52 eV and indirect = 5.12 eV) of the PVA/CMC/PEG blend were decreased upon loading with ZnS, attaining the lowest values (3.56 and 3.11) eV with ZnS prepared at 300 °C. The refractive index of the pristine blend decreased monotonically with the wavelength, while for the loaded blend, it decreased with (λ) up to 320 nm, then increased in the range 350 ≤ λ ≤ 450 nm, then decreased slowly. The NLO parameters attained their maximum values in the visible range as the blend was loaded with ZnS and prepared at 300 °C. The fluorescence emitted colors and intensities of the blended polymer depended on the prepared temperature of the nanofiller.