Study of Electrokinetic Properties of Magnetite – Silica Core – Shell Nanoparticles

In this work, the electrokinetic properties of Fe3O4 nanoparticles modified with various alkoxysilanes (tetraethoxysilane and 3-aminopropyltriethoxysilane) in various media were investigated. The determined values of the zeta potential of the Fe3O4/SiO2 samples indicate the complete coverage of nanoparticles with a tetraethoxysilane shell, as well as in the case of the Fe3O4/aminopropyltriethoxysilane. The data obtained on the zeta-potentials of modified nanoparticles with various ligands make it possible to predict the efficiency of subsequent functionalization by target molecules. A decisive role in the study of surface properties is played by cleaning from low molecular weight impurities that can screen the surface of nanoparticles or bind with an indifferent electrolyte. Thus, dispersion on a magnetic stirrer leads to an increase in the sorption capacity of the sample in comparison with ultrasonic dispersion, which causes irreversible destruction of the core-shell nanoparticle structure due to an increase in temperature and pressure in the cavities. This opens the prospective for practical application of modified nanoparticles for creation of tailored composite materials.