Effects of SiO2 Nanoparticles on Polyvinyl Alcohol/Carboxymethyl Cellulose Polymer Blend Films’ Structural, Wettability, Surface Roughness, and Optical Characteristics

The blend matrix composed of polyvinyl alcohol and carboxymethylcellulose (PVA/CMC) was prepared via the casting method. SiO₂ nanoparticles were added as reinforcement in different amounts (SiO₂ = 1, 2, 3, and 4 wt.%). The study utilized FTIR to examine the alterations in composition and the interplay between the blend matrix and the inclusion of SiO₂. Also, for the first time, the surface roughness and surface wettability of the PVA/CMC blend matrix were investigated with the addition of SiO₂ using measurements of contact angle and surface roughness parameters. The surface roughness and wettability of the blend matrix increased as the SiO₂ content increased. In addition, the blend matrix optical features were determined by the UV–visible spectrophotometer. Based on the analysis using Tauc’s relation, it was found that the energy bandgap decreases from 5.52 to 5.17 eV (direct transition) and from 4.79 to 4.32 eV (indirect transition) for the PVA/CMC and PVA/CMC/4%SiO₂ blend films, respectively. The refractive index increases from 2.009 to about 2.144 for the PVA/CMC and PVA/CMC/4%SiO₂ blend films, respectively. Furthermore, optical conductivity and dielectric constants were improved for the PVA/CMC blend film after the addition of SiO₂ nanoparticles.