Thermotropic properties of PSM/ceramide binary bilayers. DSC thermograms of pure PSM and equimolar PSM/Cer binary mixtures (1 mM final lipid concentration) were recorded between 20°C and 95°C at a temperature gradient of 1°C/min. The ceramide analogs interacted with PSM to form complex gel phases for which the transition temperature increased in a chain-length-dependent manner. Representative data of the highest phase transition peaks of the second heating scans of four independently repeated experiments are shown for 1), PSM; 2), PSM/12:1-PCer; 3), PSM/14:1-PCer; 4), PSM/16:1-PCer; 5), PSM/18:1-PCer; and 6), PSM/20:1-PCer. For clarity, only the temperature range around the main gel-to-fluid transition for each mixture is shown, and stretches that showed no remarkable features are omitted.