SURFACE-TENSION OF HELIUM-OXYGEN AND HELIUM-ETHANE SOLUTIONS

The capillary constant has been measured, and the surface tension of gas-saturated solutions of He-O-2 and He-C2H6 has been calculated in the temperature range from the solidification temperature to approximately 0.9T(c), where T-c is the critical temperature of the solvent. Measurements have been carried out along isotherms at pressures from the saturation pressure of the pure solvent to 5 MPa. Equations approximating the baric dependence of the capillary constant and the concentration dependence of the surface tension are proposed. Adsorption is determined. The data obtained are discussed within the framework of the method of a finite-thickness layer. It is shown that for the investigated solutions the approximation of a monomolecular surface layer is not justified even at temperatures lower than the normal boiling point.