Fizika Nizkikh Temperatur: Volume 44, Number 10 (October 2018), p. 1404-1411 ( to contents , go back )
Dynamic of crystallization of solid ethanol
V. Efimov, A. Izotov, and O. Rybchenko
Institute of Solid State Physics, Russian Academy of Sciences 2 Academician Ossipyan Str., Chernogolovka 142432, Russia
Received May 7, 2018, published online August 28, 2018
Experimental studies of the kinetics of phase transitions of samples of ethanol C2H5OH from amorphous to crystalline phase have shown that the rate of transitions and their energy characteristics strongly depend on the size of the samples and the composition of the sample (rectified alcohol or absolute alcohol). Massive amorphous samples with a size of several mm of rectified alcohol crystallized almost completely into the monoclinic phase in a few hours at a temperature of T ~ 125 K, while in amorphous powder samples consist of clusters of the order of tens of nm had a similar transition at T ~ 110 K. The characteristic times of transition between two crystalline phase for absolute ethanol were also very different. The temperatures of transition from the plastic phase to the monoclinic for both bulk and nanoclusters samples were lower (100–105 K), though the crystallization of nanoclusters sam-ples was much faster. The exponent in the time dependence x ~ t n for the JMAK model (crystallization of the amorphous substance) strongly depended on the temperature, and for nanocrystallites was on the order of 1 or less, while for massive samples the exponent n turned out to be closer to 2, and for the rectificate and for the absolute ethanol.
Key words: ethanol, crystallization, amorphous structures, x-ray diffraction.