抄録
Thin liquid film has been investigated by measuring the film tension as a function of independent experimental variables and analyzing the results with thermodynamic equations derived by introducing four dividing planes to define the thermodynamic quantities of bilayer as excess quantities. The film tension has been measured for the foam film of aqueous tetradecyltrimethylammonium bromide (C14TAB) and sodium bromide solution as a function of the solute concentrations. The results suggest the micro condensation of counter ions in the bilayer film of surfactant ions at the transition of common black film (CBF) to Newton black film (NBF). In addition, the film tension has been measured as a function of temperature. The excess entropy of the bilayer formation has been evaluated and confirmed to be decreased discontinuously due to the transition of CBF to NBF. This result also supports the micro condensation. Furthermore, it is demonstrated that the measurements of film tension as a function of disjoining pressure and total pressure will give us important information about the bilayer structures in thin liquid films.
