FEATURES OF PARTICLE SIZE MEASUREMENTS IN THE NANOSILICA HYDROSOL BY THE OPTICAL METHODS

The current level of study and application of nanoparticles raises the question of their classification. One of the main parameters in this case is the particle size. However, its measurement on such a small scale is a valuable problem as usual models are not correct. The article presents the results of measurements of the light attenuation in the hydrosols (dispersions of nanoparticles in water). The Rayleigh scattering theory was applied to the experimental data for obtaining the average size of nanoparticles with various specific surfaces. The obtained values were compared with the results of the transmission electron microscopy analysis and with the results of dynamic light scattering measurements. All of measurements variants presented the specified value of medium size. It could be caused by the mechanics characteristics, structure and other properties of nanoparticles related to the surface properties and their production process. The Rayleigh theory gave the undervalued particle size, and dynamic light scattering gave overvalued one in a comparison with the microscopy data. It is shown that the light transmission attenuation strongly depends from the particle size, only for particles bigger than 15 nm. For smaller particles the association was not found. There are two different particle size ranges for dynamic light scattering measurement of different produced particle.

Keywords:
silica, nanopowders, Rayleigh scattering, dynamic light scattering. 
УДК 535.361

 FEATURES OF PARTICLE SIZE MEASUREMENTS IN THE NANOSILICA HYDROSOL BY THE OPTICAL METHODS