title: Bilayers at High pH in the Fatty Acid Soap Systems and the Applications for the Formation of Foams and Emulsions.
abstract: In our previous work, we reported bilayers at high pH in the stearic acid/CsOH/H2O system, which was against the traditional viewpoint that fatty acid (FA) bilayers must be formed at the pKa of the fatty acid. Herein, the microstructures at high pH of several fatty acid soap systems were investigated systematically. We found that palmitic acid/KOH/H2O, palmitic acid/CsOH/H2O, stearic acid/KOH/H2O, and stearic acid/CsOH/H2O systems can form bilayers at high pH. The bilayer structure was demonstrated by cryogenic transmission electron microscopy (cryo-TEM) and deuterium nuclear magnetic resonance ((2)H NMR), and molecular dynamics simulation was used to confirm the formation of bilayers. The influence of fatty acids with different chain lengths (n = 10, 12, 14, 16, and 18) and different counterions including Li(+), Na(+), K(+), Cs(+), (CH3)4N(+), (C2H5)4N(+), (C3H7)4N(+), and (C4H9)4N(+) on the formation of bilayers was discussed. The stability of foam and emulsification properties were compared between bilayers and micelles, drawing the conclusion that bilayer structures possess a much stronger ability to foam and stronger emulsification properties than micelles do.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Xu
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhong
authors.forename: Liwen
authors.initials: L
authors.lastname: Jiang
authors.forename: Mengxin
authors.initials: M
authors.lastname: Xu
authors.forename: Xionglu
authors.initials: X
authors.lastname: Zhu
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Hao
mesh_terms: D004548:Elasticity; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D019308:Palmitic Acid / Q000737:chemistry*; D012915:Soaps / Q000737:chemistry*; D013229:Stearic Acids / Q000737:chemistry*; D014783:Viscosity
chemical_list: D004655:Emulsions; D008051:Lipid Bilayers; D012915:Soaps; D013229:Stearic Acids; D019308:Palmitic Acid; C031183:stearic acid