Hydration pressure and phase transitions of phospholipids. I. Piezotropic approach.

Dehydration reduces the main phase transition pressure of phospholipids. An analysis based on the Gibbs-Duhem equation shows how the shift of the transition pressure is correlated to the hydration pressure. By using Fourier transform infrared (FT-IR) spectroscopy we determined the hydration-dependent phase transition pressure. The application of our new approach gives hydration pressure values which agree with the values obtained with the osmotic stress method.