ABSTRACT
There are only two kinds of solutes that will dissolve in water: A) solutes whose molecules are repelled by the water-air interface, and B) solutes whose molecules
are attracted to the water-air interface [1]. In the first category are: A.I) solutes which increase the surface tension of water (e.g., sugars, salts) and A.II) solutes which decrease the surface tension of water (e.g., sugar polymers such as ficoll or dextran). Due to the singularities at the water-air interface of aqueous solutions of both categories (A and B), the measurable surface tension of either category of solution differs significantly from the real surface tension of the bulk (i.e., the main body) of the aqueous solution. However, the surface tension of the main body of the aqueous solution cannot be measured directly, but it can be indirectly determined from the surface tension properties of water and of the solute, in the liquid state, combined with the surface tension properties of the solid (e.g., the sugar) in the dried state.
