Effect of PVP on the morphology of cobalt nanoparticles prepared by thermal decomposition of cobalt acetate

A Novel Research on Behavior of Zinc Ferrite Nanoparticles in Different Concentration of Poly(vinyl pyrrolidone) (PVP)

“…However, in this case, it was observed that the nanoparticles did not have a uniform distribution of shapes, and they were aggregated extensively and, in some areas, completely disproportionately distributed. Thus, without the use of PVP in the synthesis of nanoparticles, the small nanoparticles aggregate and produce larger nanoparticles [24] due to high surface energy (as shown earlier in Figure 2). When the concentration of PVP was increased to 15 g/L, the zinc ferrite nanoparticles that were formed with average size of 28 nm became more regular in shape than in the case without PVP (Figure 4b).…”

“…In this step, the small nanoparticles with high surface energy levels would become larger via the Ostwald ripening process [22] without the presence of PVP, disrupt steric hindrance, thereby preventing their aggregation. Steric hindrance is a phenomenon that is attributed to large molecular weight (>10,000) and the repulsive forces acting among the polyvinyl groups [23,24]. These interactions are similar to the stabilization of metallic nanoparticles, i.e., silver and gold [25,26].…”

An Overview on Nanocrystalline ZnFe2O4, MnFe2O4, and CoFe2O4 Synthesized by a Thermal Treatment Method

“…In this step, the small nanoparticles with high surface energy levels would become larger via the Ostwald ripening process [13] without the presence of PVP, disrupts steric hindrance, thereby preventing their aggregation. Steric hindrance is a phenomenon that is attributed to large molecular weight (>10,000) and the repulsive forces acting among the polyvinyl groups [14,15]. These interactions are similar to the stabilization of metallic nanoparticles, that is, silver and gold [16,17].…”

Crystalization in Spinel Ferrite Nanoparticles

“…Thus, without the use of PVP in the synthesis of nanoparticles, the small nanoparticles aggregate and produce larger nanoparticles [29] due to high surface energy (as shown earlier in Fig15) When the concentration of PVP was increased to 0.015 gm/ml, the nickel ferrite nanoparticles that were formed became more regular in shape than in the case without PVP (Figure 17b). But, due to the low concentration of PVP, these nanoparticles also aggregated because there was insufficient PVP to cap them well and prevent their agglomeration.By increasing the PVP concentration to 0.055 gm/ml, the nickel ferrite nanoparticles did not agglomerate, and they were nearly uniform in shape, as shown in Figure 17d.…”

“…In this step, the small nanoparticles with high surface energy levels would become larger via the Ostwald ripening process [27] without the presence of PVP, disrupts steric hindrance, thereby preventing their aggregation. Steric hindrance is a phenomenon that is attributed to large molecular weight (>10,000) and the repulsive forces acting among the polyvinyl groups [28,29]. These interactions are similar to the stabilization of metallic nanoparticles, i.e., silver and gold [30,31].…”