Design and preparation of poly(vinyl alcohol) flexible nanocomposite films containing silica nanoparticles with citric acid and ascorbic acid linkages as a novel nanofiller through a green route

To prevent SiO2 nanoparticles (SNPs) from aggregation, surface modification of them was performed using bio-safe citric acid (CA) and L(+)-ascorbic acid (vitamin C) for the first time. After that, NC films of well-dispersed modified SiO2(Mod-SiO2) in a poly(vinyl alcohol) (PVA) matrix (PVA/Mod-SiO2) were prepared using the solution casting method. The prepared NC films loaded with different mass fractions (4, 8, and 12 wt.%) of Mod-SiO2 were analyzed by several techniques. Field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed that Mod-SiO2 with sizes ranging between 23–27 nm is dispersed in the PVA matrix. With thermogravimetric analysis (TGA) the amount of attached modifiers was estimated at 13 wt.%. TGA results also indicated that the incorporation of Mod-SiO2 in the PVA matrix can improve its thermal stability.