Interaction of Valinomycin and Stearic Acid in Monolayers. (Reannouncement withNew Availability Information)

摘要

Surface pressure and surface potential as functions of surface area were measuredfor monolayers of valinomycin-stearic acid mixtures on the water-gas interface. Specific area per molecule of valinomycin, free energy of mixing, and dipole moment were calculated as a function of concentration of valinomycin. The sum of the partial molecular areas in the mixture of valinomycin with stearic acid is significantly less than the calculated sum of the molecular areas of the pure components. This condensing effect is accompanied by two minima in free energy of mixing, valinomycin specific molecular area, and dipole moment, at low and high concentrations of valinomycin in mixed monolayers. Our data indicate that the miscibility of the valinomycin and the stearic acid in mixed monolayers is a function of composition. Langmuir-Blodgett deposited multilayers of mixed valinomycin-stearate monolayers were exposed to water solutions of KCL and NaC1 in a concentration range of 0.001-100mM. The electric current generated by the monolayer system in contact with electrolyte solutions was dependent on KCI concentration. In contrast, the system was not sensitive to Na+. The valinomycin-stearate multilayer thus has potential application as a potassium ion sensor.