Developments of ceramic Er2O3/ZrO2 nanoparticles boosted TPU/GO composite for flexible optoelectronic and capacitor applications

Polymer dielectric materials are attractive for high-power applications but suffer from low energy density and a trade-off between permittivity, breakdown strength, and mechanical integrity, which is exacerbated by poor filler–matrix compatibility and agglomeration. In the present study, thermoplastic polyurethane (TPU) is incorporated through the incorporation of various nanocomposites, including Er₂O₃/TPU, ZrO₂/TPU, Er₂O₃/ZrO₂/TPU, and Er₂O₃/ZrO₂/GO/TPU. The objective is to analyze the impact of each composite on TPU films, aiming to achieve superior performance in dielectric characterization. TPU dielectric composites were prepared using solution-casting technique. XRD is used to investigate the crystal structure of different phases that exist in the film. Er₂O₃/TPU, ZrO₂/TPU, Er₂O₃/ZrO₂/TPU, and Er₂O₃/ZrO₂/GO/TPU showed crystallite sizes of 33, 31.9, 32.8, and 32.9 nm, respectively. However, by using SEM, the average sizes of agglomeration of Er₂O₃ and ZrO₂ were measured at around 8.08 μm and 5.3 μm, respectively. FTIR and Raman spectroscopy were utilized to investigate the structural and elemental characteristics of nano-fillers. Additionally, the thermal properties of the Er₂O₃/ZrO₂/TPU and Er₂O₃/ZrO₂/GO/TPU nanocomposites have been studied using thermogravimetry (TGA) at temperatures from 20 to 600 °C. The mechanical properties of all samples are measured. For specimen loading, GO-filled nanocomposite demonstrates the highest value of tensile strength across 51.86 ± 0.65 MPa, and the elongation at break demonstrated an improvement, rising to 636 % ± 25 with Young's modulus at 3.75 ± 0.53 MPa and hardness value at 84 ± 0.31. Hence, the sample containing TPU/Er₂O₃/Zr₂O and GO exhibited higher ε' when contrasted with other samples at room temperature. However, the pure TPU exhibited the lowest ε', which means the dipole concentration was minimal, and the material exhibited dielectric behavior. The conductivity of the sample, which included GO, has been noted to increase by 1.3 times compared to the other sample, indicating that GO enhances the conductivity of the films. The behavior of dielectric permittivity (ε') of a sample that includes TPU/Er₂O₃ increased 1.15 times compared to the neat TPU.