Conductance and counterion activity of ionene solutions

The conductance and counterion activity of aliphatic ionenes with counterio ns of F-, Cl-, Br-, I-, and NO3- in both the absence and presence of salts were measured and compared with Manning's equations for both cases. Samples used were 3,3-, 4,5-, 6,6-, and 6,9-ionenes, where the numbers are those o f methylene groups between the quaternized nitrogen atoms. The activity coe fficients of counterions for ionenes in the absence of salts were lower tha n the theoretical values, and experimentally determined values of the charg e density parameters, higher than the theoretical ones, could explain the d eparture between the experimental and the theoretical values at least semiq uantitatively. The conductance of ionenes in the presence of salts deviated from the additivity rules, dependent on charge density of the ionenes as w ell as the counterions used. It also deviated from the theoretical predicti on in which the interaction between small ions was taken into account. On t he other hand, the additivity holds approximately for the counterion activi ty irrespective of the species of ionenes and counterions, in marked contra st to the case of conductivity. The viscosity of the ionene solution exhibi ted a strong dependence on the salts added. The effect of salts on the visc osity was more prominent in the samples with higher charge density paramete r, corresponding to larger conformational change in the polyion. These resu lts may give useful information on the conformation of ionenes in solution as well as the mechanism of the electrical conductivity of polyelectrolytes .