Novel composites of CNT/Mn3(VO4)2/Sm2O3@PVDF with superior optical and dielectric properties

Polyvinylidene fluoride (PVDF) is a broadly significant polymer that is employed in many applications. However, several application limitations arise such as low conductivity, wide optical band gap, and dielectric constant. In this study, nanocomposite films based on PVDF were fabricated by solution casting. The Mn₃(VO₄)₂, Sm₂O₃, and carbon nanotube fillers were used to achieve an enhanced PVDF film. The XRD, TGA, SEM, FTIR, and UV–Vis studies were employed to analyze the effect of the doping of these fillers on the structural, morphology, and thermal response of PVDF nanocomposites, in addition to its optical band gap. TGA revealed improved thermal stability in the CNT/Mn/Sm/PVDF film, with the primary degradation onset at 230 °C and a major weight loss of 52%, followed by a second decomposition stage ending at 660 °C, leaving a stable residue of 12%. Dielectric relaxation spectroscopy was performed to have a good insight of the dielectric behavior of the current nanocomposites across a 100 mHz–20 MHz frequency window. In addition, there was a substantial increase in dielectric permittivity which reached 242 in the CNT/Mn/Sm/PVDF film, compared to approximately 135 in Sm/PVDF and even lower in pure PVDF. Moreover, the loss tangent (tan δ) at mid-frequency dropped to < 0.4 for the composite, XRD shows crystalline peaks after Mn₃(VO₄)₂ and Sm₂O₃ doping. UV–vis calculations show the lowest indirect optical energy band gap for CNT/Mn/Sm/PVDF film where it was lowered to be 2.01 eV, when compared to 3.15 eV in unmodified PVDF film. The AC conductivity value is illustrated to be almost multiplied, being 6.2 mS cm⁻¹ for CNT/Mn/Sm/PVDF film when compared to 3.2 mS cm⁻¹ for unmodified film. Hence, the CNT/Mn/Sm/PVDF nanocomposite is proposed as a future candidate for the increasing energy applications.