Polymers adsorbed on nanoparticles (NPs) are important elements that determine the dispersion of NPs in polymer nanocomposite (PNC) films. While previous studies have shown that increasing the number of adsorbed polymers on NPs can improve their dispersion during the drying process, the exact mechanism remained unclear. In this study, we investigated the role of adsorbed polymers in determining the microstructure and dispersion of NPs during the drying process. Investigation of the structural development of NPs using the synchrotron vertical-small-angle X-ray scattering technique revealed that increasing polymer adsorption suppresses bonding between the NPs at later stages of drying, when they approach each other and come in contact. On the particle length scale, NPs with large amounts of adsorbed polymers form loose clusters, whereas those with smaller amounts of adsorbed polymers form dense clusters. On the cluster length scale, loose clusters of NPs with large amounts of adsorbed polymers build densely packed aggregates, while dense clusters of NPs with small amounts of adsorbed polymers become organized into loose aggregates. The potential for the quantitative control of NP dispersion in PNC films via modification of polymer adsorption was established in this study.

Highly porous silica pigments and PVOH binder are commonly used for inkjet coated papers. The use of PVOH increases the viscosity of coating colours and increases drying stresses in the coatings. In this study, the possibility of using S/A lattices as inkjet binders to decrease the viscosity of inkjet coatings and meet the quality requirements of the inkjet papers was investigated. Three S/A latices were prepared and tested as binders for inkjet coating. The effect of drying temperature and binder $T_g$ on the drying stress development and crack formation in the coating was investigated. The results showed that the $T_g$ of S/A latices, drying temperature, and PVC influenced the drying-stress patterns during drying. Drying stress decreased as the $T_g$ of the latex decreased and the drying temperature increased. The presence of silica pigment caused a sudden increase and then decrease of the drying stress due to cracking of the coating layer. Two S/A latices gave coating colours with lower Brookfield viscosities and drying stresses than conventional PVAc latex, and they also gave coatings similar in brightness, opacity, gloss and roughness to the conventional latex coating.