Morphology of self-assembled polyvinyl alcohol/Silica nanocomposites studied with atomic force microscopy

Summary

Atomic force microscopy (AFM) is used for the morphology study of polyvinyl alcohol/silica (PVA/SiO₂) nanocomposites prepared by incorporating solution compounding and self-assembly technique. The results show that the strong particle-particle interaction of SiO₂ nanoparticles is greatly suppressed, and the SiO₂ nanoparticles are homogenously distributed in PVA matrix as spheric nano-clusters. The average size of the SiO₂ nano-clusters is below 50 nm at low SiO₂ loadings (≤5 wt%). At higher SiO₂ contents, the particle aggregations can be clearly observed, and the average size of SiO₂ aggregates significantly reach up to 110 nm and 250 nm at SiO₂ content of 10 wt% and 15 wt%, respectively. AFM height profiles demonstrate that the surface heterogeneity of the nanocomposite is governed by the SiO₂ contents. The surface roughness evaluated as root mean square (RSM) of peak-to-valley height values shows that the surface becomes rougher as the SiO₂ content increases, particularly, a remarkable increase in surface roughness is found at the SiO₂ content of 10 wt%.