Incomplete lipid chain freezing of sonicated vesicular dispersions of double-tailed ionic surfactants
Lipid freezing in dilute sonicated vesicular dispersions was studied using differential scanning calorimetry (DSC) and H-1 NMR. For charged, anionic, or cationic lipids, approximately half of the lipids remain in a fluid state when cooled 20 degrees C below the main chain melting temperature. With a zwitterionic phospholipid, on the other hand, essentially no supercooling of the liquid state was o