Optical and electrical properties of polystyrene composites containing ultrafine iron particles

Abstract

Optical and electrical properties of conductive polymer composites made of polystyrene (PS) containing ultrafine iron particles of size 2 μm were studied under different measuring conditions: iron filler concentrations (0, 5, 10, 20, and 30 wt.%), ultraviolet radiation wavelength, temperature range (30–90°C), and applied frequency range (50 kHz–1.5 MHz). The absorption spectra from the composites were measured using a spectrophotometer. The analysis of the optical results showed that the electronic transitions are direct in the k-space. The optical energy gap and the energy tails were determined as a function of iron particles’ content. It was found that optical energy gap decreased and energy tails increased with iron content. The determined refractive index ( n) and the extinction coefficient ( k) increased with iron concentration. The alternating current (AC) conductivity and dielectric properties were determined using impedance measurements. The collected impedance data were analyzed and showed that the dielectric constant ( ε′) and dielectric loss ( ε″) of the composites are increasing as iron concentration increases and decreasing as the applied frequency increases. It was found that the AC conductivity increases with increasing frequency, temperature, and iron concentration. Some theoretical and empirical models are used to describe the observed optical and electrical behavior of the prepared PS composites.