アミノ酸水溶液の界面化学的性質

抄録

The interfacial properties of some amino acids in their aqueous solutions were studied in terms of surface and interfacial tension of the solutions. Dodecane was used as a non-polar oil phase and oleic acid as a polar oil phase at the oil/water interface. Surface and interfacial tension decreased with increas-ing concentration of amino acids. Increasing hydrophobicity of amino acid side chain (Δft) tends to decrease surface and interfacial tension in the same concentration of amino acids. The Δft is an average of differences of standard free energy change on the basis of glycine when amino acid is transfered from organic solvent to water. This is considered that hydrophobic amino acids are difficult to exist in the bulk, because water molecules in the neighborhoods of amino acid side chains form ice-berg structure.Basic amino acids and oleic acid formed salt at the interface and the character of its salt was similar to that of lyotropic mesomorphism. Interfacial tension decreased considerably at dodecane containing oleic acid/basic amino acid solution interface.