engleski

Kinetics of Growth of Submicrometer Crystalline Lanthanum Fluoride Particles Using the pF-stat Method

The constant composition method (pF-stat method) was employed to prepare submicrometer-size (few tens to several hundred nanometers), very stable, positively charged LaF3 particles of narrow size distribution in the acidic pH region from 4 to 4.5. The polarising microscopic pictures (anisotropic clusters) and DLS data demonstrate that submicrometer structure is self-similar and fractal with the dimension going on from Df = 1.4 to 2.1 (ą0.05), i.e. the aggregation process proceeds from diffusion limited to reaction limited with increasing the supersaturation of solution. In acidic solution the pF-stat rate obeys the kinetics of the first order (p=1.09 ą0.08). Also the rate of growth from the DLS data i.e. the slope of the change of the normalized median hydrodynamic diameter with mass increment (which is proportional with time) is about 1 (exactly increases from 0.85 to 1.05, with increasing the supersaturation).

Constant composition method of crystal growth ; Dynamic light scattering - Hydrodynamic diameter ; Lanthanum fluoride ; Particle aggregation - Fractal dimension ; pF-stat kinetics of crystal growth.

Rad u časopisu navedenom u Pravilniku iz NN 2/97.