title: Adsorption and micellization behavior of novel gluconamide-type gemini surfactants.
abstract: The adsorption and micellization behavior of novel sugar-based gemini surfactants (N,N(')-dialkyl-N,N(')-digluconamide ethylenediamine, Glu(n)-2-Glu(n), where n is the hydrocarbon chain length of 8, 10 and 12) has been studied on the basis of static/dynamic surface tension, fluorescence, dynamic light scattering (DLS) and cryogenic transmission electron microscope (cryo-TEM) data. The static surface tension of the aqueous Glu(n)-2-Glu(n) solutions measured at the critical micelle concentration (cmc) is observed to be significantly lower than that of the corresponding monomeric surfactants. This suggests that the gemini surfactants, newly synthesized in the current study, are able to form a closely packed monolayer film at the air/aqueous solution interface. The greater ability in the molecular association is supported by the remarkably (approximately 100-200 times) lower cmc of the gemini surfactants compared with the corresponding monomeric ones. With a combination of the fluorescence and DLS data, a structural transformation of the Glu(n)-2-Glu(n) micelles is suggested to occur with an increase in the concentration. The cryo-TEM measurements clearly confirm the formation of worm-like micelles of Glu(12)-2-Glu(12) at the concentration well above the cmc.
authors.affiliation: Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan. k-sakai@rs.noda.tus.ac.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakai
authors.forename: Shin
authors.initials: S
authors.lastname: Umezawa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tamura
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Takamatsu
authors.forename: Koji
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Kanjiro
authors.initials: K
authors.lastname: Torigoe
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Kunio
authors.initials: K
authors.lastname: Esumi
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
mesh_terms: D000327:Adsorption; D000388:Air; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000737:chemistry; D020285:Cryoelectron Microscopy; D005453:Fluorescence; D005942:Gluconates / Q000737:chemistry*; D008823:Micelles; D015394:Molecular Structure; D010316:Particle Size; D012542:Scattering, Radiation; D012996:Solutions / Q000737:chemistry; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: C411462:1,25-dihydroxy-21-(3-hydroxy-3-methylbutyl)vitamin D(3); D005942:Gluconates; D008823:Micelles; D012996:Solutions; D013501:Surface-Active Agents; D014867:Water; C018954:gluconamide; D002117:Calcitriol