title: Partition coefficients of 1-alkanols between water and DDAB vesicle membrane determined by differential conductivity method.
abstract: The partition coefficients of 1-alkanols between water and didodecyldimethylammonium bromide (DDAB) vesicle membrane, and the change of the degree of counter-ion dissociation on DDAB vesicle caused by the solubilization of 1-alkanols were determined from electric conductivity measurements. A good linear relationship was obtained between logarithmic value of the partition coefficient and carbon number of alkyl chain in 1-alkanols. The standard transfer free energy change per methylene group was evaluated from the slope of this straight line. On the other hand, the effect of 1-alkanols on the degree of counter-ion dissociation was independent of carbon number of 1-alkanols. Comparing the results of the present system with those of sodium dodecylsulfate (SDS) micelle/1-alkanol system, it was found that the interior of DDAB vesicle membrane is more hydrophobic than that of SDS micelles. Furthermore, the increase in counter-ion dissociation caused by solubilized 1-alkanols was much lesser for DDAB vesicles than SDS micelles.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Niihama National College of Technology, Niihama, Ehime, Japan. kawamura@chem.niihama-nct.ac.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Manabe
authors.forename: Masako
authors.initials: M
authors.lastname: Myoujou
authors.forename: Hajime
authors.initials: H
authors.lastname: Katsuura
authors.forename: Masaki
authors.initials: M
authors.lastname: Shiomi
mesh_terms: D000473:Alkanes / Q000032:analysis* / Q000737:chemistry*; D004553:Electric Conductivity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D000473:Alkanes; D000644:Quaternary Ammonium Compounds; D014867:Water; C046112:didodecyldimethylammonium