title: A role of the anteiso branch of 18-MEA in 18-MEA/SPDA to form a persistent hydrophobicity to alkaline-color-treated weathered hair.
abstract: The effect of the anteiso-branch moiety of 18-MEA (18-methyleicosanic acid) to create a persistent hydrophobicity of alkaline-color-treated weathered hair treated with 18-MEA/SPDA (stearoxypropyldimethylamine) was investigated by comparing a straight-chain fatty acid (n-heneicosanoic acid, n-HEA) and an iso-branch fatty acid (19-methyleicosanic acid, 19-MEA) with the anteiso-branch fatty acid (18-MEA), using dynamic contact angle measurements, quantification of 18-MEA by LC/MS, and temperature controlled atomic force microscopy (AFM). The dynamic contact angle measurements indicated that the anteiso-branch moiety of 18-MEA is critical for the creation of a persistent hydrophobicity to alkaline-color-treated weathered hair. The temperature-controlled AFM investigations revealed that the anteiso-branch moiety of 18-MEA in the 18-MEA/SPDA system produces a persistent hydrophobicity to alkaline-color-treated weathered hair by providing higher fluidity to the upper region of the 18-MEA/SPDA layer.
authors.affiliation: Beauty Research Center, Kao Corporation, Sumida-ku, Tokyo, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tanamachi
authors.forename: Shigeto
authors.initials: S
authors.lastname: Inoue
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tokunaga
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tsujimura
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tanji
authors.forename: Masashi
authors.initials: M
authors.lastname: Oguri
authors.forename: Taichi
authors.initials: T
authors.lastname: Habe
mesh_terms: D002853:Chromatography, Liquid; D004537:Eicosanoic Acids; D006197:Hair / Q000737:chemistry*; D006202:Hair Dyes; D006801:Humans; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force
chemical_list: D004537:Eicosanoic Acids; D006202:Hair Dyes; C111345:18-methyleicosanoic acid