Jie, Y. S.; Jia, D.

Ions perform crucial functions in biological systems. However, the understanding of the relation between polyelectrolyte gel and ion is confined to the effects of swelling by salt solutions on macro- and micro-properties of gel. Here we explore the microstructure evolution of gel with changing crosslinking density and concentration of types of salts measured by dynamic light scattering (DLS). The dissociation-association of the ion bonds will induce a stretched exponential mode in the correlation function. The stretched exponent {beta} reflects the subchain dynamics of gel strands and undergoes a transition from 0.33 to 0.5 when the multivalent salt concentration increases to the vicinity of phase separation boundary. It demonstrates that the Gaussian chain-like gel strands with Rouse dynamics transform into molten-globule-like strands with Zimm dynamics at high multivalent salt concentration.