Julia A. Zakharova

EFFECT OF POLYCARBONIC ACIDS ON THE MOLECULAR MOBILITY OF CATIONIC SURFACTANTS IN MICELLES

Abstract The rotational mobility of a spin probe in the micelles of alkyltrimethylammonium bromides and in their complexes with poly(acrylic acid) and poly(methacrylic acid) has been studied at pH 6. Formation of the polyelectrolyte–surfactant complexes (PSC) causes the decrease in the molecular mobility of surfactant ions in the PSC micelles as compared with the micelles of the free surfactant. It was found that the surfactant ion mobility in PSC micelles is almost independent of the complex composition and even its phase state. The chemical structure of the polyacid has little effect on the molecular mobility of the surfactant ions in the micelles of the complexes. It was shown that the rotational mobility of the surfactant ions in micelles depends on the hydrocarbon chain length of surfactant molecules. Increase in surfactant ion alkyl chain length causes the decrease of their molecular mobility in micelles. Dissociation of the ionic bonds between polyelectrolyte and the surfactant as a result of the increase in the concentration of NaCl in the solution leads to the enhancement of the mobility of the surfactant ions in PSC micelles. It was shown that solubilization of isopropyl alcohol in complex micelles leads to an increase of surfactant ion mobility even at a very low (

Self-organization in complexes of polyacids with oppositely charged surfactants

Abstract Formation and structure of water-soluble complexes of alkyltrimethylammonium bromide homologues (AlkTAB) with poly(acrylic acid) (PA) of different polymerization degrees at pH 5.7 have been examined by elastic and quasi-elastic laser light-scattering and high-speed sedimentation technique. It was experimentally shown that generation of intramolecular micellar phase is the necessary condition for formation of PA-AlkTAB complexes. Minimum aggregation number of the surfactant ions in the complex micelle was found to be close to that of the surfactant micelles in polymer-free solution. The structure of the polyelectrolyte-surfactant complexes (i.e. a phase state of the complex, conformation of the polyion coil and the surfactant ion aggregation number) was shown to be largely determined by PA polymerization degree.

Macromolecular and morphological evolution of poly(styrene sulfonate) complexes with tetradecyltrimethylammonium bromide.

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.

Effect of Phase Transitions in the Solutions of the Complexes of Ionic Surfactants with Oppositely Charged Polyelectrolytes on the Molecular Mobility of Surfactant Ions inside Intracomplex Micelles

The effect of phase transitions in the solutions of the complexes of surfactants and oppositely charged polyelectrolytes of different chemical natures on the molecular mobility of the surfactant ions inside the intracomplex micelles was studied by the spin probe method. It was found that, irrespective of the fact whether the solutions of the polyelectrolyte–surfactant complexes are true solutions, colloidal dispersions, or thixotropic gels, the molecular mobility of the surfactant ions inside the complex micelles and, consequently, the local structure of the intracomplex micelles, remain unchanged upon both a change in the complex composition and transition of complexes from solution to the precipitate.

Correction to: Controlled modification of Nafion membrane withcationic surfactant

The author noticed that the published paper contained error. Unfortunately, Eq. 1 in page 5 is missing even though the author noted a comment about the equation missing when submitting the proofs. Given in this paper is the missing equation.