FRENCH-UKRAINIAN JOURNAL OF CHEMISTRY (2019, VOLUME 07, ISSUE 01) 57 Influence of water-soluble nonionic polymers adsorption on colloidal properties of nanosilica dispersions Olena V. Goncharuk a,b* , Maria L. Malysheva c , Konrad Terpilowski d , Salvador Pérez Huertas d , Volodymyr M. Gun’ko a a Chuiko Institute of Surface Chemistry of NAS of Ukraine, Kyiv, Ukraine b Ovcharenko Institute of Biocolloidal Chemistry of NAS of Ukraine, Kyiv, Ukraine c Department of Chemistry, Taras Shevchenko National University of Kyiv, Ukraine d Faculty of Chemistry, Maria Curie-Sklodowska University, Lublin, Poland iscgoncharuk@meta.ua Keywords: polymer adsorption, nanosilica aqueous dispersion, poly(vinyl alcohol), poly(ethylene oxide), poly(vinyl pyrrolidone), aggregative and sedimentation stability, rheological properties. The relationships between the adsorption of poly(vinyl alcohol) (PVA), poly(ethylene oxide) (PEO), and poly(vinyl pyrrolidone) (PVP) of various molecular weights onto nanosilica and the stability and rheological properties of the aqueous dispersions were analyzed. The adsorption isotherms for the polymers correspond to the Langmuir-type isotherms. The adsorption maximum slightly increases with increasing molecular weight of the polymers. The sedimentation and aggregative stability of the silica dispersion decreased at a low amount of an adsorbed polymer (less than a monolayer). At this polymer content, a significant increase in the viscosity of dispersions is observed due to the formation of polymeric bridges between silica nanoparticles from neighboring aggregates of them. If the amount of adsorbed polymer exceeds the monolayer then the stabilizing effect is observed due to the steric factor preventing the bridge formation and the viscosity of dispersion decreases slightly compared with systems with a low polymer content. ________________________________________________________________________________ Introduction The behavior of polymers at the interfaces of polymer solution/solid surface plays an important role in the properties of dispersions in liquid media and in the formation of filled polymer materials [1-7]. The adsorption of polymers leads to changes in the interactions of covered solid particles with neighboring particles and dispersion medium. These changes depend on the component types and concentrations, as well temperature, pH and salinity of the media. Stabilization of aqueous dispersions by polymers is widely used in pharmacy for preparation of stable pharmaceutical substances, food industry, manufacture of products with a