Enhancement of dielectric properties of the La2NiO4-CuO terpolymer nanocomposites by modified SiC nanofiller

Abstract

This work investigates the enhancement of dielectric properties of La2NiO4-CuO terpolymer nanocomposites using surface modified SiC nanoparticles as fillers. SiC nanoparticles were subjected to acid treatment and annealing at 1000 °C to tailor the surface chemistry. Acid treatment involved immersing the SiC powder in a mixture of H2SO4 and HNO3 acids and sonicating for 30 min, followed by stirring at 60 °C for 6 h. Annealing was carried out at 1000 °C for 2 h in an inert argon atmosphere. La2NiO4 and CuO nanoparticles were synthesized by sol-gel and precipitation techniques respectively, with average particle sizes of 20–40 nm and 10–15 nm confirmed by XRD and FESEM. Nanocomposites were fabricated by dispersing 2–10 wt% of untreated, acid treated and annealed SiC nanoparticles in a La2NiO4-CuO mixture solution, using PVDF as the polymer matrix. Impedance spectroscopy revealed that addition of 5 wt% acid treated SiC resulted in the highest dielectric constant of 42 at 1 kHz, in comparison to 25 for the unfilled polymer. This was attributed to increased interfacial polarization arising from uniform dispersion of nanoparticles and abundant charge trapping sites introduced by the SiC filler.