title: Adsorption behavior of lauric acid at heptane/water interface as studied by second harmonic generation spectroscopy and interfacial tensiometry.
abstract: Interfacial tensiometry and second harmonic generation (SHG) spectroscopy were applied to examine the adsorption behavior of lauric acid (LA) at a heptane/water interface. From interfacial tensiometry measurements, the adsorption kinetics of LA was revealed to be diffusion-controlled, and the adsorption constant of LA was estimated to be 9.6 x 10(4) M(-1). The adsorption isotherms obtained by SHG measurements were analyzed by taking account of both the molecular orientation of LA at the interface and a surface electric field generated by the adsorbed LA layer. It was confirmed that the carboxylic groups of adsorbed LA molecules were well ordered at the heptane/water interface and the orientation of the carboxylate group was invariant during the adsorption process.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Uchida
authors.forename: Kimihisa
authors.initials: K
authors.lastname: Nochi
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Yamashita
authors.forename: Norio
authors.initials: N
authors.lastname: Teramae