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The formation and structure of water‐soluble complexes of partly neutralized poly(acrylic acid) (PA) and poly(diallyldimethylammonium chloride) (PDADMAC) with oppositely‐charged surfactants [tetradecyltrimethylammonium bromide (C14AB) and sodium dodecyl sulfate (SDS)] have been studied by elastic and quasi‐elastic laser light‐scattering, high‐speed sedimentation and viscometry techniques. It was shown that minimum aggregation number (nmin) of the surfactant ions in the complex micelle depends on the chemical structure of the polyelectrolyte. In particular, C14AB interacting with PA in dilute water solutions forms PA bound micelles with nmin of 102 similar to spherical micelles formed by free C14AB. This is in contrast to soluble PDADMAC–SDS complex species, which are most probably vesicles, each containing ca 105 surfactant ions instead of 102 characteristic for free SDS spherical micelles. A shift from a dilute to a semi‐dilute solution regime with respect to the free PDADMAC results in drastic rearrangement of the PDADMAC–SDS complex structure. Copyright © 2003 Society of Chemical Industry

Surface tension of kraft lignin (KL) and KL/poly(N,Ndimethylaminoethyl methacrylate) mixtures, with different composition at the air-water interface depending on pH and temperature, was measured. It was found that the surface activity of both KL and the reaction mixtures grows with decreasing pH and increasing temperature. At the same time, the surface activity of the KL/poly(N,Ndimethylaminoethyl methacrylate) reaction mixture, irrespective of its composition under the same environment conditions, considerably exceeds the surface activity of KL, indicating the synergetic effect governed by the peculiarities of the polymeric structure of the formed soluble particles of the polyelectrolyte complex.

Macromolecular characteristics and morphology of water-soluble complexes between sodium poly(styrene sulfonate) (PSS) and tetradecyltrimethylammonium bromide have been followed as a function of surfactant-to-polymer charge ratio (S/P) to elicit possible changes in the complexation mechanism. As revealed by light scattering, shorter PSS (30 and 150 repeat units) yield multichain complexes while longer PSS (450 and 5000 repeat units) form single-chain species throughout 0 < S/P < 0.9. Irrespective of PSS chain length, the complexes exist in solution in a swollen coil conformation and undergo a compaction with S/P but never collapse into a globule. Even when the free PSS chain is too short to coil (30 repeat units), the complexes adopt a coiled conformation due to multichain aggregation. Morphological changes (manifested by a hypochromic shift in UV spectra of the complexes at S/P < 0.5 and an increase in the local surfactant mobility observed at S/P > 0.5 by ESR) strongly suggest a change in the formation mechanism of the complexes with a transition near S/P = 0.5.