Separation by polyelectrolyte complexation*

Polyelectrolyte complexation can be used to separate protein molecules in simple and complex protein mixtures [1, 2. In addition, small molecules can partition into complex coacervates [3], e.g., the  partitioning of butanol strongly depends on the temperature. In all cases, the partitioning or take up of protein molecules strongly depends on the composition of the system.

To understand why molecules partition into complex coacervates or are taken up by polyelectrolyte complexes it would be useful to be able to measure where all components are after phase separation. Recently we have been able to measure the composition and concentrations of polyanions and polycations as well as sodium and chloride in the dense and dilute phase with NMR. This allow us to set up the complete mass balance. Having access to this mass balance will allow us to study why compounds partition or are taken up.

This talk I will conclude by discussing some other ways by which polyelectrolyte complexation can be used to separate components. Here I will discuss the formation of porous membranes and porous-free membranes. These membranes can be used for water purification and ion-exchange processes. To both membrane types proteins can be added to give them additional functionality.