The correlation between activities of polyelectrolytes, measured by the light‐scattering and osmotic methods

Abstract

Abstract The aim of this work was to demonstrate the clear‐cut correlation between the results of light‐scattering and osmotic measurements, primarily in the case of polyelectrolytes. The correlation is expressed to terms of formulas whose forms are adapted to the specific nature of each of the several possible kinds of comparison. Experimental results of both methods are given for water solutions of ionized PMA, PAA, and BSA. A special technique for the optical clarification was found to be indispensable for obtaining reasonably reliable light scattering results. The osmotic measurements were carried out in a special concentration osmometer. The osmotic coefficients ϕ, calculated from the results of both methods, are compared and found to be in reasonable accord. This justifies, in our belief, the use of light scattering as a method for measuring the activities of ionized polyelectrolytes. The method of treating the results is shown to be advantageious also in the case of nonelectrolytes.