Dynamic properties of phospholipid-water multilayers studied by dielectric relaxation spectroscopy

The authors report on thermally stimulated depolarization currents (TSDC) measurements in the temperature range 77-320 K on hydrated di-myristoil-phosphatidylcholine at different water contents up to 0.33 w/w, corresponding to approximately 18 water molecules per lipid molecule. The different relaxation mechanisms contributing to the complex thermograms are analyzed using special TSDC techniques, and the corresponding spectra of activation energies and entropy factors are determined. The results are discussed in terms of different structures of water in the context of multiphase model and head group mobilities