Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films

Dispersions of nanoparticles (NPs) in a polymer matrix are a key element to set various properties of solution-cast polymer nanocomposite films. While the dispersion state of NPs in nanocomposite films has been extensively studied over the past decades, the structural development during drying and the relation of liquid and solid structure still remains poorly understood. In the present work, we study how NP dispersions develop during drying in polymer nanocomposite films, particularly focusing on the role of particle–polymer interaction in the structural development. Aqueous dispersions of nanosilica and poly(vinyl alcohol) are used as model NP/polymer mixtures, where the particle–polymer interaction can systemically be varied via the pH. A novel vertical small-angle X-ray scattering technique enables us to directly observe the development of the NP’s dispersion state during drying. At …