title: Solution properties of amino acid-type new surfactant.
abstract: The solution properties of an amino acid-type new surfactant, N-[3-lauryloxy-2-hydroxypropyl]-L-arginine L-glutamate (C12HEA-Glu), were examined by means of pK(a), surface tension, light scattering and fluorescence measurements. The dissociation state of C12HEA-Glu was changed by varying pH of the aqueous solution. The critical micelle concentration (cmc) of aqueous solution of C12HEA-Glu was lowest at pH 5.6 and the cmc increased with decreasing pH. The aggregation number of C12HEA-Glu micelles was largest at pH 5.6 and decreased with decreasing pH. The surface tension-concentration curve for C12HEA-Glu in water (non-buffered solution) showed a minimum. This is considered to be due to the coexistence of a trace species and a main species of C12HEA-Glu with various dissociation states since the pH of aqueous solution of C12HEA-Glu changes with the concentration of C12HEA-Glu. The micropolarity in the micelles of C12HEA-Glu was almost independent of pH, while the microfluidity in the micelles increased with increasing pH.
authors.affiliation: Ajinomoto Co., Inc., Amino Science Laboratories, 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, 210-8681, Kanagawa-ken, Japan
authors.initials: T
authors.lastname: Tabohashi
authors.initials: K
authors.lastname: Tobita
authors.initials: K
authors.lastname: Sakamoto
authors.initials: J
authors.lastname: Kouchi
authors.initials: S
authors.lastname: Yokoyama
authors.initials: H
authors.lastname: Sakai
authors.initials: M
authors.lastname: Abe