title: A long ripple phase in DLPC-decylglucoside mixture evidenced by synchrotron SAXS coupled to DSC.
abstract: For the first time, the secondary ripple phase in a system containing dilauroyl phosphatidylcholine (DLPC) is observed by small-angle X-ray diffraction (SAXS). The SAXS profile exhibits many well-resolved peaks. The fast formation of this phase upon cooling from the liquid crystalline lamellar phase L(alpha) is induced by addition of C10G with molar ratio 0.17< or = R = [C10G]/[DLPC]< or = 0.49. For R < 0.17, the primary P(beta') ripple phase is observed. In contrast to the P(beta') phase, which shows a sawtooth shape, the secondary ripple structure is thought to be symmetric. The ripple length (190 angstroms) and the bilayer spacing (74 angstroms) are larger than in the primary ripple phase. Lattice parameters of the new long ripple phase, which are quite insensitive to temperature, vary slightly linearly with R. In this study, structural and thermodynamic changes within the samples were followed as a function of temperature by time-resolved X-ray diffraction coupled to DSC.
authors.affiliation: LURE, Université Paris-Sud, Bâtiment 209D, 91405 Orsay Cedex, France.
authors.forename: Louisa
authors.initials: L
authors.lastname: Dahbi
authors.forename: Michal
authors.initials: M
authors.lastname: Arbel-Haddad
authors.forename: Pierre
authors.initials: P
authors.lastname: Lesieur
authors.forename: Claudie
authors.initials: C
authors.lastname: Bourgaux
authors.forename: Michel
authors.initials: M
authors.lastname: Ollivon
mesh_terms: D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005960:Glucosides / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*; D017356:Synchrotrons; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D005960:Glucosides; D010713:Phosphatidylcholines; C002448:1,2-linoleoylphosphatidylcholine