Effect of Counterion Condensation on Polyelectrolytes at the Air-Water Interface

The condensation of counterions on a polyelectrolyte (PE) is a well established phenomenon in aqueous solution and it has important consequences for the properties of PEs in many types of mixture including biological systems. However, very little is known experimentally about its consequences for equilibrium aqueous surfaces. In the case of the air-water interface, there are no experimental results that have been successful and correctly interpreted. This means that there is no sound basis for understanding the surface behavior of mixtures involving a PE as one of the components. We propose to do parallel ST, NR measurements on a perdeuterated sample of NaPSS(MW:~24K) We would regard the experiment as a first stage in trying to elucidate the effect of the dilute-semidilute transition on the surface properties, which requires higher MW or higher concentrations.