ИСТИНА

Current work is aimed at the study of the new type of surfactant-polymer complexes consisting of anionic surfactant potassium oleate and polymer, insoluble both in water and hydrocarbons, poly(4-vinylpiridine) (P4VP) in the presence of inorganic salt KCl. Concentration of KCl was fixed at 6 wt% and pH at 11. Weight-average molecular weights (MW) of P4VP were determined by static light scattering (SLS) and were shown to be equal 77000 and 228000 g/mol. To study the range of phase miscibility, phase diagram surfactant/polymer was plotted for solubilized polymers of both MWs. In distinction from polyelectrolyte-ionic surfactant complexes [4] the studied system demonstrated wide range of phase miscibility. In order to determine potassium oleate/P4VP ratio in the surfactant-polymer complex saturated by polymer the elemental analysis of the dried supernatant and precipitant was used. The MW of the saturated complexes was determined by SLS. From the results of elemental analysis and SLS the chemical composition of the P4VP-saturated complex was obtained. Several experimental methods were applied to investigate the inner structure of the complex. Nuclear magnetic resonance was used to acquire the information about the localization of macromolecules in WLMs. P4VP in micellar aggregates was located at the interface between hydrocarbon core and hydrophilic corona. By using contrast variation technique in small-angle neutron scattering structural parameters of wormlike micelles (radius Rc, surfactant mass per micelle unit length ML) and properties of the embedded polymer, such as its conformation and persistence length lp, were received. It was shown, that polymer-loaded WLMs keep their cylindrical shape with Rc equal to the radius of the surfactant hydrophobic tail. Increase of the amount of polymer, solubilized by WLMs led to the increase of ML. The form of polymer-loaded micelles was also confirmed by cryo-TEM images. Macromolecules of P4VP associated with the micelles had an expanded coil-like conformation with persistence length lp 4-fold higher than that of a polymer chain in a good solvent. Viscoelastic properties of the P4VP-loaded WLMs were studied using rheology. From rheological data the following parameters of the transition network of P4VP-loaded WLMs were attained: number of the elastically active strands ν, mesh size of the network ξ, average contour length of WLMs . Viscosity of the system decreased with the increase of the concentration of embedded P4VP, due to the polymer-induced shortening of WLMs. The drop of the viscosity occurs when the number of added macromolecules is approximately equal to the number of elastically active strands in micellar network. Value of the viscosity of the solutions containing WLMs saturated by polymer was close to the viscosity of a pure solvent.