title: Pickering emulsions with α-cyclodextrin inclusions: Structure and thermal stability.
abstract: This paper explores structural, interfacial and thermal properties of two types of Pickering emulsions containing α-cyclodextrin inclusion complexes: on one hand, emulsions were obtained between aqueous solutions of α-cyclodextrin and different oils (fatty acids, olive oil, silicone oil) and on the other hand, emulsions were obtained between these oils, water and micro or nano-platelet suspensions with inclusion complexes of hydrophobically-modified polysaccharides. The emulsions exhibit versatile properties according to the molecular architecture of the oils. Experiments were performed by microcalorimetry, X-ray diffraction and confocal microscopy. The aptitude of oil molecules to be threaded in α-cyclodextrin cavity is a determining parameter in emulsification and thermal stability. The heat flow traces and images showed dissolution, cooperative melting and de-threading of inclusion complexes which take place progressively, ending at high temperatures, close or above 100°C. Another important feature observed in the emulsions with micro-platelets is the partial substitution of the guest molecules occurring at room temperature at the oil/water interfaces without dissolution, possibly by a diffusion mechanism of the oil. Accordingly, the dissolution and the cooperative melting temperatures of the inclusion crystals changed, showing marked differences upon the type of guest molecules. The enthalpies of dissolution of crystals were measured and compared with soluble inclusions.
authors.affiliation: Laboratoire de Physique Thermique, ESPCI-ParisTech, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France.
authors.forename: Raul
authors.initials: R
authors.lastname: Diaz-Salmeron
authors.affiliation: Laboratoire de Physique Thermique, ESPCI-ParisTech, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France; Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Denis Diderot-Paris 7, Case Courrier 7056, 10 Rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France.
authors.forename: Ismail
authors.initials: I
authors.lastname: Chaab
authors.affiliation: Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Denis Diderot-Paris 7, Case Courrier 7056, 10 Rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Carn
authors.affiliation: Laboratoire de Physique Thermique, ESPCI-ParisTech, PSL Research University, 10 rue Vauquelin, 75231 Paris cedex 05, France. Electronic address: Madeleine.Djabourov@espci.fr.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Djabourov
authors.affiliation: Institut Universitaire de France, Institut Galien Paris Sud, UMR CNRS 8612, Univ. Paris-Sud, Université Paris Saclay, Faculté de Pharmacie, 5, rue J-B. Clément, 92296 Châtenay-Malabry cedex, France.
authors.forename: Kawthar
authors.initials: K
authors.lastname: Bouchemal
mesh_terms: D003460:Crystallization; D004058:Diffusion; D004655:Emulsions; D005227:Fatty Acids / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D000069463:Olive Oil / Q000737:chemistry*; D012827:Silicone Oils / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D047391:alpha-Cyclodextrins / Q000737:chemistry*
chemical_list: D004655:Emulsions; D005227:Fatty Acids; D000069463:Olive Oil; D012827:Silicone Oils; D047391:alpha-Cyclodextrins; D014867:Water; C032613:alpha-cyclodextrin
keywords: Crystalline α-cyclodextrin inclusions; Enthalpy dissolution and melting; Nano-platelets; Pickering emulsion