Accurate determination of liquid viscosity and surface tension using surface light scattering (SLS): Toluene under saturation conditions between 260 and 380 K

Abstract

Earlier reported values of the liquid kinematic viscosity and surface tension of the reference fluid toluene between 263 and 383 K under saturation conditions from surface light scattering have been recalculated. For this, an improved data evaluation scheme based on an exact description of the hydrodynamic capillary wave problem for a liquid-vapor interface has been applied. The maximum adjustments amount to 0.9 and 0.6% for the liquid kinematic viscosity and surface tension, respectively. These changes are within the uncertainties as stated in our original work which demonstrates that for the surface light scattering technique a total uncertainty of better than 1.0% for both properties of interest also holds for the revised data of the present work. Thus, in spite of the additional complexity connected with this very precise data evaluation procedure presented here, the surface light scattering technique could still be used with less complexity for a reliable determination of surface tension and liquid kinematic viscosity with an accuracy comparable or even better than that of conventional methods. While almost all of these conventional methods determine viscosity and surface tension in a relative manner with two completely different sets of experimental equipment, for the surface light scattering technique no calibration procedure is needed and both properties can be determined simultaneously without any extra effort.