Effect of electrostatic interactions between these ions and the charged monomer of polyelectrolyte on the chain conformation and the rheological behavior is a fundamentally important issue for engineering application of polyelectrolyte/ILs systems.Rheological behavior of a polyelectrolyte

sodium polystyrene sulfonate (NaPSS)

in 1-allyl-3-methylimidazolium chloride (AmimCl) has been investigated and compared to that in AmimCl/H2O co-solvent solutions.Mole of chain segment unit per liter (mol/L) is used to define the concentration of NaPSS.The results show that

NaPSS in AmimCl solution shows different rheological behaviors from which in salt-free aqueous solution

added salt aqueous solution and neutral polymer in ionic liquid solution.Rheological behaviors of NaPSS in AmimCl/H2O co-solvent solutions are also different from each other.With increasing AmimCl concentration

intrinsic viscosity[η] of NaPSS in AmimCl/H2O decreases

indicating the decline of chain coil size of NaPSS.NaPSS in AmimCl/H2O co-solvent show the rheological behaviors changing from salt-free polyelectrolyte solution to neutral polymer in θ solvent with increasing AmimCl concentration.When the solvent changes into pure AmimCl

NaPSS in AmimCl solution is divided into two concentration regimes in the range from 0.007 mol/L to 0.8 mol/L.Dynamic frequency sweep shows that NaPSS chain does not overlap in the concentration regime bellow 0.29 mol/L

where the power laws for the concentration dependence of specific viscosity and terminal relaxation time are ηsp~cp1.4 and τ~cp0

respectively

similar to theoretical prediction for salt-free polyelectrolyte solutions in entangled regime.The concentration regime above 0.29 mol/L is considered as semidilute un-entangled regime

where the power laws for the concentration dependence of specific viscosity and terminal relaxation time are ηsp~cp3.5 and τ~cp1.9

respectively

closing to theoretical prediction for neutral polymer in good solvents in entangled regime.The unique phenomenon may be caused by the high electrostatic coupling of monomer-ion and monomer-monomer.