title: An ESR study of the hydration steps of lecithin multilayers.
abstract: A spin-labeled stearic acid and other spin-labeled molecules have been used for an ESR study of the hydration process of the egg lecithin lamellar phase for water concentrations, CW greater than 10%. Two hydration steps are found for CW approximately 20% and CW congruent to 30%, in good agreement with results of the literature. To explain discontinuities in the behavior of three spin-labeled molecules at CW congruent to 20%, a conformational change of the phosphatidylcholine polar head and a phase transition in the polar interface are proposed.
mesh_terms: D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy; D006860:Hydrogen Bonding; D008567:Membranes, Artificial; D008954:Models, Biological; D008968:Molecular Conformation; D010713:Phosphatidylcholines; D013113:Spin Labels; D013229:Stearic Acids; D013696:Temperature; D014867:Water
chemical_list: D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D013113:Spin Labels; D013229:Stearic Acids; D014867:Water