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Polymer/surfactant Complexes (surfactant + complex)
Selected AbstractsRole of the Preparation Procedure in the Formation of Spherical and Monodisperse Surfactant/Polyelectrolyte ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007Yuxia Luan Dr. Abstract Complexes formed by a double-tail cationic surfactant, didodecyldimethyl ammonium bromide, and an anionic polyelectrolyte, an alternating copolymer of poly(styrene-alt-maleic acid) in its sodium salt form, were investigated with respect to variation in the charge ratio (x) between the polyelectrolyte negative charges and the surfactant positive charges. The morphology and microstructure of the complexes were studied by light microscopy and small-angle X-ray scattering for different preparation conditions. Independent of the sample preparation procedure and the charge ratio x, the X-ray results show that the microscopic structure of the complexes is a condensed lamellar phase. By contrast, the morphology of the complexes changes dramatically with the preparation procedure. The complexes formed by mixing a surfactant solution and a polyelectrolyte solution strongly depend on x and are always extremely heterogeneous in size and shape. Surprisingly, we show that, when the two solutions interdiffuse slowly, spherical complexes of micrometric and rather uniform size are systematically obtained, independently on the initial relative amount of surfactant and polyelectrolyte. The mechanism for the formation of these peculiar complexes is discussed. [source] Investigation of binary polymer/surfactant or ternary polymer/surfactant/Cu2+ complexes in aqueous solution through Nile red probingPOLYMER INTERNATIONAL, Issue 8 2010Zacharoula Iatridi Abstract The optical properties (absorption and emission) of Nile red have been widely used for staining or probing purposes in diverse aqueous systems. However, the applications of Nile red for the determination of the critical aggregation concentration of polymer/surfactant complexes or for the investigation of ternary polymer/surfactant/Cu2+ systems are very limited. The interactions between anionic polyelectrolytes and the oppositely charged surfactant N,N,N,N -dodecyltrimethylammonium chloride were investigated in dilute aqueous solution, exploiting the optical properties of Nile red. It is shown that the emission properties of Nile red present better sensitivity than its absorption properties, concerning the detection of the hydrophobic polymer/surfactant complexes formed in aqueous solution. Moreover, it is found that the formation of ternary polymer/surfactant/Cu2+ complexes leads to a pronounced quenching of the luminescence of Nile red. The corresponding Stern,Volmer plots indicate that quenching is more favourable when coordination of Cu2+ ions with poly(sodium acrylate) takes place, as compared to simple electrostatic binding of these ions with poly(sodium styrene sulfonate). Nile red is a sensitive and accurate tool, as an alternative to pyrene, for the characterization of binary polymer/surfactant complexes or for obtaining information on the local arrangement of ternary polymer/surfactant/Cu2+ systems in aqueous solution. Copyright © 2010 Society of Chemical Industry [source] Spectral, kinetic, and redox properties of basic fuchsin in homogeneous aqueous and sodium dodecyl sulfate micellar mediaINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2003N. Ramanathan Effect of anionic surfactant on the optical absorption spectra and redox reaction of basic fuchsin, a cationic dye, has been studied. Increase in the absorbance of the dye band at 546 nm with sodium dodecyl sulfate (SDS) is assigned to the incorporation of the dye in the surfactant micelles with critical micellar concentration (CMC) of 7.3 × 10,3 mol dm,3. At low surfactant concentration (<5 × 10,3 mol dm,3) decrease in the absorbance of the dye band at 546 nm is attributed to the formation of a dye,surfactant complex (1:1). The environment, in terms of dielectric constant, experienced by basic fuchsin inside the surfactant micelles has been estimated. The association constant (KA) for the formation of dye,SDS complex and the binding constant (KB) for the micellization of dye are determined. Stopped-flow studies, in the premicellar region, indicated simultaneous depletion of dye absorption and formation of new band at 490 nm with a distinct isosbestic point at 520 nm and the rate constant for this region increased with increasing SDS concentration. The reaction of hydrated electron with the dye and the decay of the semireduced dye are observed to be slowed down in the presence of SDS. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 629,636, 2003 [source] Controlling the photoluminescence of water-soluble conjugated poly[2-(3-thienyl)ethyloxy-4-butylsulfonate)] for biosensor applicationsPOLYMER INTERNATIONAL, Issue 5 2007Enrique López-Cabarcos Abstract The photoluminescence of poly[2-(3-thienyl)ethyloxy-4-butylsulfonate)] (PTE-BS) in aqueous solution increases threefold on addition of the surfactant tetrabutylammonium perchlorate (TBA). Furthermore, the luminescence of the PTE-BS/TBA system is reduced by more than five times by the addition of small amounts of the cationic electron acceptor methyl viologen (MV2+). The Stern,Volmer constant KSV = 1.4 × 104 L mol,1 for the quenching of the polymer,surfactant complex by MV2+ is approximately 60 times smaller than the KSV = 8.4 × 105 L mol,1 obtained in water polymer solutions without surfactant. Thus, the luminescence of PTE-BS in aqueous solution can be modulated by complexing the polymer either with a surfactant or with a quencher. In this contribution we show that the surfactant/quencher tuning effect found in polymers of the phenylenevinylene family, such as poly(2,5-methoxy-propyloxysulfonate phenylenevinylene), also appears in polymers of the thiophene family such as PTE-BS. Copyright © 2007 Society of Chemical Industry [source] Macroscopically Aligned Ionic Self-Assembled Perylene-Surfactant Complexes within a Polymer Matrix,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2008Ari Laiho Abstract Ionic self-assembled (ISA) surfactant complexes present a facile concept for self-assembly of various functional materials. However, no general scheme has been shown to allow their overall alignment beyond local polydomain-like order. Here we demonstrate that ionic complexes forming a columnar liquid-crystalline phase in bulk can be aligned within polymer blends upon shearing, taken that the matrix polymers have sufficiently high molecular weight. We use an ISA complex of N,N,-bis(ethylenetrimethylammonium)perylenediimide/bis(2-ethylhexyl) phosphate (Pery-BEHP) blended with different molecular weight polystyrenes (PS). Based on X-ray scattering studies and transmission electron microscopy the pure Pery-BEHP complex was found to form a two-dimensional oblique columnar phase where the perylene units stack within the columns. Blending the complex with PS lead to high aspect ratio Pery-BEHP aggregates with lateral dimension in the mesoscale, having internal columnar liquid-crystalline order similar to the pure Pery-BEHP complex. When the Pery-BEHP/PS blend was subjected to a shear flow field, the alignment of perylenes can be achieved but requires sufficiently high molecular weight of the polystyrene matrix. The concept also suggests a simple route for macroscopically aligned nanocomposites with conjugated columnar liquid-crystalline functional additives. [source] Effect of organic additives on formation and structure of polyelectrolyte-oppositely charged surfactant complexes,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2006J. A. Zakharova Abstract Effect of butanol and Triton X-100 on formation, supramolecular organization and local dynamics of poly(N -ethyl-4-vinylpyridinium)-dodecyl sulfate complexes have been studied by UV spectroscopy, high-speed sedimentation, laser light scattering and electron spin resonance (ESR) spectroscopy. It was found that solubilization of butanol promotes aggregation of the complex species in solution and results in contraction of the region in which water-soluble complexes are formed. On the contrary, highly aggregated complexes disaggregate up to molecularly dispersed state upon addition of Triton X-100. It was found that under the experimental conditions neither butanol (up to 3,wt%) nor Triton X-100 ([Triton X-100]/[sodium dodecylsulfate],,,1:1) cause destruction of the complexes. The results of ESR spin probe and spin label studies show that in both cases supramolecular realignments are accompanied by a slight increase of the local molecular mobility of surfactant ions in the complex micelles, segmental mobility of polyelectrolyte being unchanged. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||