The conductance and counterion activity of aliphatic ionenes with counterions 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 of methylene groups between the quaternized nitrogen atoms. The activity coefficients of counterions for ionenes in the absence of salts were lower than the theoretical values, and experimentally determined values of the charge density parameters, higher than the theoretical ones, could explain the departure between the experimental and the theoretical values at least semiquantitatively. The conductance of ionenes in the presence of salts deviated from the additivity rules, dependent on charge density of the ionenes as well as the counterions used. It also deviated from the theoretical prediction in which the interaction between small ions was taken into account. On the other hand, the additivity holds approximately for the counterion activity irrespective of the species of ionenes and counterions, in marked contrast to the case of conductivity. The viscosity of the ionene solution exhibited a strong dependence on the salts added. The effect of salts on the viscosity was more prominent in the samples with higher charge density parameter, corresponding to larger conformational change in the polyion. These results may give useful information on the conformation of ionenes in solution as well as the mechanism of the electrical conductivity of polyelectrolytes.

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SUMMARY: A new poly(carboxybetaine) whose main chain is composed of peptide bonds was synthesized from poly(c-methyl L-glutamate). The side chains of poly(c-methyl L-glutamate) were exchanged to carboxybetaine structures by three reactions. Our new poly(carboxybetaine) has 84% carboxybetaine structures in the side chains, as determined by 1 H NMR measurements. The presence of betaine structures in the side chains was confirmed by viscosity measurements.

SYNOPSISA membrane, which has positively charged groups in the polymer main chain, was prepared from polyethylenimine by crosslinking and successive alkylation. Dibromoalkane was used as a crosslinking agent. The crosslinked membrane was alkylated using methyl iodide under several conditions. Elemental and ICP emission analyses were introduced to measure the rates of alkylation and quaternization. From the membrane potential measurement, the effective charge density was estimated. The highest value was about 1.0 M, which was obtained by a prolonged alkylation time. This value was larger than that of some commercial ion exchange membranes. The effective charge density, which was obtained by the last alkylation procedure, was 10 times larger than that of the former one, though the rate of quaternizing increased by less than a factor of two. This implies that the activity constant in the membrane increased when the charge density is increased.