The thesis is devoted to the establishment and systematic study of the relationship between the composition, surface structure and morphology of mixed nanooxides and the properties of their aqueous dispersions, namly zeta potential, rheological properties, aggregation and sedimentation stability. The structure and morphology of mixed nanooxides of different compositions, synthesized by the pyrogenic method and using deposition on the surface of the carrier, were preliminary investigated by a set of methods: SEM, low-temperature adsorption-desorption of nitrogen, X-ray diffraction, IR, and Auger spectroscopy. The influence on the stability of water-soluble non-ionic polymers, potential-determining and non-indifferent electrolytes, surfactants is considered. The features of the polymers adsorption from aqueous solutions and the polymer adsorption layer formation in aqueous dispersions have been studied. Special attention is devoted to the study of the hydrophilic/hydrophobic properties of mixed nanooxides, initial and modified with various functional groups and polymers. Based on the results obtained, the highly dispersed hydrophobic composites and superhydrophobic coatings filled with oxides nanoparticles have been developed. The structure and physical properties of polymers in the interfacial layer of composites have been investigated and it has been shown that the length of the polymer chain and the method of modification, namely chemical grafting or physical adsorption, determine the ratio between the rigid and mobile fractions of the polymer, which affects the properties of the composite as a whole. Composite materials based on nanooxides and hydrophilic polymers, such as natural polysaccharides, have been developed for the sorption of metal ions from aqueous solutions. It is shown that the adsorption activity of such composites is determined by the morphology, specific surface area, and polysaccharide structure, which is manifested in the features of the pH dependence of adsorption. Composite hydrogels based on poly (N-isopropylacrylamide) physically crosslinked by magnetite/laponite nanooxide composites have been developed, which have proved synergy of properties and multifunctionality: a sharp phase transition at physiological temperatures, an increased degree of equilibrium swelling, cooperative dehydration, enhanced absorbing capacity and magnetic sensitivity, which makes them promising materials for biomedical applications.
Key words: mixed nanooxide composites, aqueous dispersions, aggregative and sedimentation stability, polymers adsorption, hydrophilic-hydrophobic properties, immersion wetting, polymer-oxide composites.
