The Structural Properties of Anisotropic Solutions of Soap as Determined by a New Centrifugal Falling Ball Method

Soap solutions are unique in that over a wide range of higher concentrations at temperatures from room temperature up to one or two hundred degrees they are doubly refracting and constitute the only easily accessible examples of liquid crystals. Nevertheless, apart from a few photographs published by McBain and the original curious observations of Lehmann on the double conic shape assumed by free drops of ammonium oleate, no study of their liquid crystalline properties has yet appeared, and not even an approximate measurement of their mechanical properties has been recorded in the literature. It is, therefore, of immediate interest to characterize them as being clear, colorless, faintly opalescent, anisotropic liquids whose apparent viscosity is several hundred times greater than that of vaseline at room temperatures. For these reasons we have begun the systematic investigation of their properties.