Molecular-surface forces in binary solutions

Abstract A formula is deduced for the potential energy of a molecule of solute in a dilute solution of low concentration as a function of an interface distance. A procedure is suggested for the determination of this energy by using the measurement of the flow rate of the solution across a membrane under the action of a concentration gradient. The flow rate of the solution is measured by means of a radioactive tracer and related to the energy of solute molecules on the basis of the thermodynamics of irreversible steady processes. An example of such measurements is given; the applicability of the calculations is not quite clear due to possible effect of electro-osmosis.