Crystallization behavior of DSPE in dimethyl sulfoxide by time-resolved infrared spectroscopy and differential scanning calorimetry

Abstract

Phase behavior of distearoylphosphatidylethanolamine (DSPE) dispersed in excess dimethyl sulfoxide has been examined by differential scanning calorimetry (DSC) and time-resolved Fourier-transform infrared spectroscopy (FT-IR). Transformation from lamellar-crystalline to liquid-crystalline phase was found to take place at temperature near 94°C upon initial heating and transformation from liquid-crystalline to lamellar-gel phase took place near 81°C during cooling scans. The kinetics of the transformation from liquid crystalline phase to lamellar-gel phase were analyzed by the well-known Avrami equation. The apparent Avrami exponents were found to be about 3 by DSC and time-resolved FT-IR. The effective dimensionality of the growth pattern can then be set as 2.

Keywords:

• Phospholipid
• Crystallization
• Avrami equation
• Time-resolved Fourier-transform infrared spectroscopy
• Dimethyl sulfoxide

Acknowledgments

Support by grants from the Natural Science Foundation of China (NSFC) and from the key-faculty supporting scheme of the Ministry of Education of China are gratefully acknowledged.