Коллоидный журнал

Amorphous titanium dioxide (TiO₂) nanoparticles were synthesized via a sol–gel reaction using titanium tetrachloride (TiCl₄) as the precursor. Acrylic acid (AA) was introduced to modify the particle surface, preventing aggregation and enabling functionalization. Fourier transform infrared analysis revealed that a reaction time of 48 hours was necessary to complete the surface modification through chelation and condensation. To optimize processing conditions, reactions were performed at 25 °C and 50 °C with varied TiO₂: AA molar ratios. Results showed that at 50 °C, excessive AA (1:14) led to over-polymerization, while insufficient AA (1:6) failed to stabilize the particles. In contrast, the intermediate concentration (1:10) produced well-dispersed spherical nanoparticles (10-15 nm), as confirmed by dynamic light scattering (DLS) and transmission electron microscope (TEM). This study demonstrates that tuning AA concentration and reaction temperature enables kinetic control over surface modification, effectively stabilizing amorphous TiO₂ in aqueous media. It offers a simple and scalable approach for preparing size-controlled, surface-functionalized amorphous TiO₂ nanoparticles with potential optical and functional applications.

Silver nanoparticles (AgNPs-E) biosynthesized at room and boiling T, stabilized by blackberry plant extracts (E) obtained by maceration at room T and reflux extraction at boiling T, are presented in this work. The obtained AgNPs-E were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) and zeta potential measurement. XRD analysis confirmed that the 2θ peak at 38.2°, corresponding to the (111) plane, was the most intense, with the average crystallite size in the range of 18.0±3 − 21.1±2 nm. SEM spectroscopy showed that spherical shapes of nanoparticles dominate in the reaction mixture. EDX spectroscopy showed the presence of elemental silver in the formed AgNPs-E, along with the presence of C and Mg, which probably originate from the biomolecules of the extracts. DLS provides the size distribution with the average particle size in the range of 50.93±0.83 − 74.48±1.84 nm, with negative zeta potential ranged from -25.87±1.63 mV to -0.3027±0.36 mV indicating the AgNPs stability. The antimicrobial activity of AgNPs-E was tested by microdilution method confirming that both nanoparticles and extracts show the ability to inhibit all the bacteria and a fungus tested. The presented results suggest further investigations of synthesized AgNPs-E for application in topical cosmetic preparations.