Coupled diffusion of segments and counterions in polyeletrolyte gels and solutions

摘要

Pulsed field gradient NMR and dynamic light scattering results revealed that the dynamical properties of chain segments and counterions in a polyelectrolyte gel are almost identical to those in a polyelectrolyte solution. The NMR results show that the dependence of the self-diffusion of a counterion on the degree of chain neutralization in the poly(acrylate) gel hardly differs from that in a normal poly(acrylate) solution. Dynamic light scattering of the poly(acrylate) gel demonstrates the existene of the fast dynamic mode whose characteristic time is of the same order as that observed in the poly(acrylate) solution. It is shown that the formalism of coupling theory, coupling the dynamics of the polyelectrolyte segments and the counterions, in valid both for polyelectrolyte solutions and for the gel system. The observed similarity of the dynamics in solutions and in gel systems is consistent with this theoretical concurrence.