title: Deposition of 18-MEA onto alkaline-color-treated weathered hair to form a persistent hydrophobicity.
abstract: A technology for the deposition of a persistent hydrophobicity to alkaline-color-treated weathered hair surfaces using 18-MEA (18-methyleicosanoic acid) is presented. Two approaches were examined in order to make 18-MEA bind tightly to the alkaline-color-treated weathered hair surface. One was to apply 18-MEA as an acid form and the other was to apply 18-MEA as a salt or complex. It was found that the combination of 18-MEA with specific cationic surfactants [stearoxypropyldimethylamine (SPDA) and docosyldimethylamine (DSDA)] makes the alkaline-color-treated weathered hair surface hydrophobic and that its hydrophobicity is maintained even after shampooing. Characterization of adsorbed layers of 18-MEA/SPDA on a mica surface, as a possible hydrophilic surface model, was performed using atomic force microscopy (AFM) and angle-resolved X-ray photoelectron spectroscopy (AR-XPS). The results revealed that 18-MEA/SPDA formed a layer with high wear resistance, with an alkyl chain, the hydrophobic moiety, oriented at an angle of around 25 degrees to the air interface.
authors.affiliation: Beauty Research Center, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tanamachi
authors.forename: Shigeto
authors.initials: S
authors.lastname: Inoue
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tanji
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tsujimura
authors.forename: Masashi
authors.initials: M
authors.lastname: Oguri
authors.forename: Mio
authors.initials: M
authors.lastname: Ishita
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tokunaga
authors.forename: Fumiko
authors.initials: F
authors.lastname: Sazanami
mesh_terms: D000328:Adult; D000468:Alkalies / Q000008:administration & dosage*; D004537:Eicosanoic Acids / Q000008:administration & dosage*; D005260:Female; D006197:Hair / Q000737:chemistry*; D006203:Hair Preparations; D006801:Humans; D018625:Microscopy, Atomic Force; D013499:Surface Properties
chemical_list: D000468:Alkalies; D004537:Eicosanoic Acids; D006203:Hair Preparations; C111345:18-methyleicosanoic acid