title: Adsorption of multilamellar tubes with a temperature tunable diameter at the air/water interface.
abstract: The ethanolamine salt of 12-hydroxy stearic acid is known to form tubes having a temperature tunable diameter. Here, we study the behavior of those tubes at the air/water interface by using Neutron Reflectivity. We observed that tubes indeed adsorbed at this interface below a fatty acid monolayer and exhibit the same temperature behavior as in bulk. There is however a peculiar behavior at around 50 °C for which the increase of the diameter of the tubes at the interface yields an unfolding of those tubes into a multilamellar layer. Upon further heating, the tubes re-fold and their diameter re-decreases after which they melt into micelles as observed in the bulk. All structural transitions at the interface are nevertheless reversible. This provides to the system a high interest for its interfacial properties because the structure at the air/water interface can be tuned easily by the temperature.
authors.affiliation: Laboratoire Léon Brillouin, CEA-CNRS, CEA Saclay, 91191 Gif sur Yvette Cedex, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Fameau
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Douliez
authors.forename: François
authors.initials: F
authors.lastname: Boué
authors.forename: Frédéric
authors.initials: F
authors.lastname: Ott
authors.forename: Fabrice
authors.initials: F
authors.lastname: Cousin
mesh_terms: D000327:Adsorption; D000388:Air; D008823:Micelles; D044367:Phase Transition; D013229:Stearic Acids / Q000737:chemistry*; D044366:Transition Temperature; D014867:Water
chemical_list: C539357:12-hydroxy stearic acid; D008823:Micelles; D013229:Stearic Acids; D014867:Water