Study of the Kinetics of the Phase Transition of the First Order in Tetracosane C24H50 by Fourier-Transform IR Spectroscopy

Resumo

The kinetics of the development of the structural phase transition of the first order in monodisperse samples of tetracosane C₂₄H₅₀ has been studied using Fourier-transform IR spectroscopy. Temperature dependences of frequencies and intensities of rocking (in the region of  ν ~ 720 cm^–1) and bending (in the region of  ν ~ 1470 cm^–1) vibration modes of CH₂ groups in trans methylene sequences in crystalline cores of elementary lamellae has been analyzed. It has been shown that the solid-phase transition of the first order develops by the heterogeneous mechanism in a narrow temperature interval ΔT ~ 2 K according to the theory of diffuse phase transitions of the first order and is caused by changes in the symmetry of crystallographic cells.