title: Observation of buried water molecules in phospholipid membranes by surface sum-frequency generation spectroscopy.
abstract: We investigate the structure and orientation of water molecules at the water-lipid interface, using vibrational sum-frequency generation in conjunction with a maximum entropy phase retrieval method. We find that interfacial water molecules have an orientation opposite to that predicted by electrostatics and thus are likely localized between the lipid headgroup and its apolar alkyl chain. This type of water molecule is observed for phospholipids but not for structurally simpler surfactants.
authors.affiliation: FOM Institute for Atomic and Molecular Physics, Sciencepark 104, 1098XG Amsterdam, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Sovago
authors.forename: Erik
authors.initials: E
authors.lastname: Vartiainen
authors.forename: Mischa
authors.initials: M
authors.lastname: Bonn
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D019277:Entropy; D010743:Phospholipids / Q000737:chemistry*; D013057:Spectrum Analysis; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D010743:Phospholipids; D014867:Water