Mechanical properties and stability of multimacroion domains in polyelectrolyte solutions

Abstract

Mechanical properties and stability of multimacroion domains in polyelectrolyte solutions were investigated by passing domains through micropores with dimensions smaller, comparable or larger than domain dimensions. This was achieved by pressure filtration of salt-free sodium poly(styrene sulfonate) solutions through membrane filters with various pore sizes and subsequent static and dynamic light scattering measurements. This process proved to be interesting to investigate since it provides an experimental tool for getting more information on these so far weakly understood structures. In addition, filtration in general is a routine procedure used in light scattering from polymers. Results from this work show that this procedure substantially influences experimental data on domains and it is necessary to know how. This is important when measuring and discussing the influence of various physicochemical factors, which may have a much weaker effect themselves. Some literature data should be accordingly accepted with caution. Natural size distribution of domains (size distribution unaffected by filtration procedure) was calculated from scattering data and subsequently verified by filtration through a set of filters with various pore sizes.