Production of a versatile PMMA/PEO-CuO-In2O3 nanocomposite with its characterization, cold plasma treatment, and applications for flexible emission filter devices and smart moisture

In this study, we synthesized versatile, flexible films with interesting optical and moisture properties. We blended poly (methyl methacrylate) (PMMA) and polyethylene oxide (PEO) and incorporated copper oxide (CuO) and indium oxide (In₂O₃) nanoparticles within the blend. We have investigated the optical properties. As the amount of CuO+In₂O₃ nanoparticles increases, the extinction coefficient and Urbach energy rise while the indirect band gap falls. The luminescence spectroscopy showed very narrow and interesting peaks, indicating that it is suitable for emission filters. We analyzed the surface morphology using FE-SEM and a photomicrograph. We also investigate the frequency dependence of AC electrical conductivity, dielectric constant, and dielectric loss. At a frequency of less than 3 MHz, AC conductivity is very low, then increases to reach 7.6E-8, 1.3E-7, 1.6E-7, 1.7E-7, and 2.5E-7 for the pure blend, 1.5, 3, 4.5, and 6 nanoparticle concentrations, respectively. We used a DC plasma sputtering device with an aluminium target to treat the nanocomposites with argon plasma (for 7 minutes). We characterized the optical and surface properties of the samples both before and after the plasma treatment. Despite the short treatment time, the plasma effect was evident only on the nanocomposites containing nanoparticles. It lowered the energy gap for the indirect transition by 0.35, 0.04, and 0.46 eV in films with 3, 4.5, and 6 wt% of CuO+In₂O₃ nanoparticles, respectively. The nanocomposites wrap around themselves when exposed to moisture, suggesting their potential applications as moisture sensors or indicators, self-wrapping materials, self-deploying or controlled release structures, or smart polymer coverings.