NC State
Kim, S., Sung, S. H., Lim, S., and Ahn, K. H. (2018). "Particle dispersion in silica-poly(vinyl alcohol) coatings: Role of particle-polymer interaction," BioRes. 13(2), 3195-3207.


Silica nanoparticle (SiNP)-poly(vinyl alcohol) (PVOH) coating is an important material system in paper coating applications, where particle distribution critically affects coating performance. In the present study, the authors investigated a role of physicochemical interaction between SiNP surface and PVOH chain in SiNP distribution in the coating layer, with a comparison of the suspension at pH 3 (good interaction) and pH 10 (poor interaction) as PVOH concentration was varied. Rheological properties and sedimentation behavior of the suspensions showed the dispersion stability of SiNP at pH 3 was improved by the addition of PVOH, whereas it was independent of the PVOH concentration at pH 10. Scanning electron microscopy and small angle x-ray scattering intensity of dried coating layer showed the uniform and dense structure with homogeneous distribution of SiNPs at pH 3, where spatial arrangement of SiNPs depended on the addition of PVOH. However, non-uniform and porous structures with SiNP aggregates were observed at pH 10, where the spatial arrangement of SiNPs was independent to the addition of PVOH. The stress development during drying of the coating suggested that the mechanical property was related to the spatial arrangement of individual SiNPs at pH 3, whereas to the distribution of SiNPs aggregates at pH 10.

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