Angular Dissymmetry of the Critical Opalescence in Liquid Mixtures

Visible light scattered by a one-component homogeneous liquid in the vicinity of its critical point or by a homogeneous mixture of two liquids in the vicinity of their critical mixing temperature shows angular dissymmetry which becomes the more pronounced the nearer the temperature comes to the critical temperature. It is shown how this dissymmetry can be used as a measure for the range of molecular forces in the case of ordinary molecules. In the case of polymer molecules, observation of the dissymmetry provides a method for measuring the size of polymer coils in a size range too small to be measured by the usual dissymmetry method applied to diluted solutions.