Open AccessDetermination of phase transition temperatures (melting, crystallization, rotator phases) of n-alkanes by the optical method
Author(s) -
Vladimir N. Kuryakov,
D. D. Ivanova,
A N Tkachenko,
P N Sedenkov
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/848/1/012044
Subject(s) - supercooling , alkane , crystallization , melting point , materials science , phase transition , phase (matter) , dispersion (optics) , emulsion , atmospheric temperature range , dynamic light scattering , glass transition , thermodynamics , analytical chemistry (journal) , chemistry , chromatography , hydrocarbon , optics , organic chemistry , nanotechnology , composite material , polymer , physics , nanoparticle
The temperatures of phase transitions (melting, crystallization, rotator phases) were determined for a number of individual n -alkanes from C 19 H 40 ( n -nonadecane) to C 28 H 58 ( n -octacosane) by the optical method, a modified droplet technique. For this research, n -alkanes were presented as an emulsion in water without the addition of surfactants. Emulsions were prepared by ultrasonic dispersion of a small amount of n -alkane in water at a temperature above the melting point of the investigated n -alkane. The hydrodynamic radius of the dispersions measured by the dynamic light scattering (DLS) method was about 100 nm and did not change within a wide temperature range within the measurement accuracy. The temperatures of melting, crystallization, and rotator phase transitions of pure n -alkanes in the form of emulsion were determined from temperature-dependent measurements of the light scattering by the dispersions. The supercooling values for studied n -alkanes were also determined.