Solubility equilibria and thermodynamic functions of two-dimensional J-aggregate of pseudoisocyanine organized on model AgX surface

摘要

By using a high-quality Ag(111)film covered with a bromide monolayer(a monolayer model of the AgX surface)as the substrate well-defined solubility equilinria were observed for the first time for the two-dimensional(2D)J-aggregate of pseudoisocyanine (PIC)perchlorate in both aqueous and ethanolic solutions. The 2D J-aggregation isotherms gave a sharp rise at a well-defined critical dye concentration or threshold reflecting the characteristic solubility of the PIC 2D J-aggregate, which was several orders of magnitude smaller than that known for the homogeneous J-aggregation in a far more concentrated aqueous PIC solu- tion. The results allowed quantitative determination of the solubility product and the related thermodynamic functions.