title: Temperature-induced sedimentation to dispersion of ionic vesicles.
abstract: We present a temperature-induced sedimentation/dispersion transition of ionic vesicles in the system of alkyldimethylamine oxide hemihydrochloride (CnDMAO.1/2HCl) with a hydrocarbon chain length of 12-16 (n = 12, 14, and 16) and sodium 2-naphthalenesulfonate (NaNphS). The temperature-sensitive sedimentation/dispersion of ionic vesicles took place around a temperature of 50 degrees C, which was weakly dependent on the alkyl chain length. The combined effect of the thermally induced dissociation of the counterions from the vesicle and a hydrogen bonding between the nonionic and the cationic head groups is likely to be responsible for this unique behavior.
authors.affiliation: Department of Chemistry, Faculty of Science, Kyushu University 33, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. hkawascc@mbox.nc.kyushu-u.ac.jp
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Masahiko
authors.initials: M
authors.lastname: Miyahara
authors.forename: Mats
authors.initials: M
authors.lastname: Almgren
authors.forename: Göran
authors.initials: G
authors.lastname: Karlsson
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maeda
mesh_terms: D011232:Chemical Precipitation; D020285:Cryoelectron Microscopy; D004123:Dimethylamines / Q000737:chemistry; D004586:Electrophoresis; D008081:Liposomes / Q000737:chemistry*; D008859:Microscopy, Polarization; D009282:Naphthalenesulfonates / Q000737:chemistry; D009391:Nephelometry and Turbidimetry; D010087:Oxides / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D004123:Dimethylamines; D008081:Liposomes; D009282:Naphthalenesulfonates; D010087:Oxides; D013501:Surface-Active Agents; C014518:dodecyldimethylamine oxide