電気二重層微分容量における吸着の研究　ＩＩ　　水銀‐溶液界面における界面活性剤の吸着

• Published in: Journal of Home Economics of Japan Vol. 30; no. 9; pp. 807 - 811
• Main Authors: WATANABE Akira, TAGAWA Mieko, OKAMURA Yoshimi
• Format: Journal Article
• Language: Japanese
• Published: 一般社団法人 日本家政学会 1979; The Japan Society of Home Economics
• ISSN: 0449-9069; 1884-7870
• DOI: 10.11428/jhej1951.30.807

The differential capacity (C) of mercury-surfactant solution interfaces was measured at various applied potentials (E) by using Grahame's AC bridge method with the dropping mercury electrode. The C-E curves obtained showed two or more dynamic peaks at anodic and cathodic polarizations. The capacity suppression which occured over the polarization range between these peaks, the zero polarization range, increased with increasing surfactant concentrations in accordance with theoretical expectation. The height of dynamic peaks depended on the concentration and diffusion constant of surfactant, and was in quantitative agreement with the Lorenz-Möckel theory. The minimum capacity over the zero polarization range (Cm) decreased with increasing surfactant concentrations at first, converging to a limiting value at sufficiently high concentrations (Cm∞). The value of Cm∞ for anionic surfactants is in general smaller than that of cationic ones, and hence the average thicknesses of adsorbed layer (d) of the former ones are larger than those of the latter ones. It was also found that values of Cm∞ and d depend on the length of hydrocarbon chain of surfactants. 界面活性剤の吸着現象に関する基本的な情報を得る目的で水銀-界面活性剤溶液界面における微分容量を測定し, 吸着層構造を検討した.微分容量Cと分極電圧Eの関係を示す曲線は理論から予想される形を与え, 動的ピークの高さは界面活性剤濃度と拡散係数依存性を示し, Lorenz-Möckel 理論に従うことが証明された.零分極領域における極小微分容量Cmは界面活性剤濃度が増加するにつれて低下し, ある濃度以上で一定値Cm∞に達した.Cm∞はπ電子を有するピリジン環やベンゼン環をもつ界面活性剤では小さい.Cm∞を用いて算出した吸着層の平均の厚さdは界面活性剤の疎水基が長くなると大きくなる傾向が認められた.