Abstract
Osmosedimentation of Na+ /K+ poly(styrene sulfonate) aqueous solutions at 3000 rpm creates polyelectrolyte and counterion concentration gradients; Na+ and K+ gradients are not identical and Na+ /K+ separation factors as high as 1.04 are obtained. Solutions of Na+ /K+ Blue Dextran and poly(acrylate) were also examined, but in the last case there was no detectable separation of the two countercations. The results are interpreted by considering the differences in Na+ and K+ ion mobilities in water, as well as their relative binding abilities to the polyanions.