Polyelectrolyte complexes IV. Interpolyelectrolyte complexes between some polycations with N,N-dimethyl-2-hydroxypropyleneanunonium chloride units and poly(sodium styrenesulfonate) in dilute aqueous solution

We report first on the interpolyelectrolyte complex formation (PEC) between one polycation of integral type having about 95 mol% of N,N-dimethyl-2-hyd roxypropyleneammonium chloride units in the backbone (PCA(5)) and poly(sodi um styrenesulfonate) (NaPSS), in dependence on the polyion concentrations a nd the mixing order. The PEC formation was qualitatively followed by viscom etry, conductometry and UV-spectroscopy. Quasi-soluble PECs could be formed in the polyion concentration range of 0.1-1.0 unit mM. A complex stoichiom etry close to 1:1 was found by both the qualitative measurements on the for mation of quasi-soluble PEC in dilute aqueous solutions (when PCA(5) concen tration was lower than the overlap concentration, C < C*) and elemental ana lyses of the insoluble PEC formed at the high polycation concentration (50 unit mM, C much greater than C*). The influence of the ionic strength on th e PECs stability was followed by the subsequent addition of NaCl up to an i onic strength of 3.5 M on the reaction mixture, after the PECs formation wi th three polycations different by both the content of quaternary ammonium s alt groups in the backbone and the degree of branching (PCA(5), PCA(20) and PCT20). No dissociation of PECs into the original components was evidenced irrespective of the polycation structure and the mixing order. (C) 2001 Pu blished by Elsevier Science Ltd.