Presence Of Polystyrene Sulfonate Research Articles

One-Pot Electrodeposition of a PANI:PSS/MWCNT Nanocomposite on Carbon Paper for Scalable Determination of Ascorbic Acid

In recent years, there has been growing demand for the monitoring of ascorbic acid levels, especially in underdeveloped populations where ascorbic acid deficiency affects up to 74% of individuals. To facilitate widespread ascorbic acid screening, we have developed a highly scalable conductive polymer nanocomposite with excellent ascorbic acid sensing performance. The material is based on polyaniline, which is deposited in a single step in the presence of polystyrene sulfonate and multi-walled carbon nanotubes onto carbon paper. The modified electrodes take advantage of the electrocatalytic properties of polyaniline toward ascorbic acid, which are boosted by the proton donating polystyrene sulfonate polymer and the high surface area of the multi-walled carbon nanotubes. The morphology and composition of the composite are characterized using field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy and the electrochemical characteristics are examined using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode shows good ascorbic acid sensing characteristics, with a linear range of 1–400 μM, a sensitivity of 546 μA mM−1 cm−2, and a limit of detection of 0.11 μM. High performance and low cost results in a promising platform to support the widespread, cheap monitoring of ascorbic acid deficiency.

Insights into the precipitation kinetics of CaCO3 particles in the presence of polystyrene sulfonate using in situ small-angle X-ray scattering.

The formation of calcium carbonate (CaCO3) nanoparticles (NPs) in the presence of polystyrene sulfonate (PSS) as an additive was examined by time-resolved small-angle X-ray scattering (SAXS) in a flow system that mimics experimental conditions used at home facilities where the precipitation can be achieved in a beaker. The experiments were carried out at low concentrations to remain in the dilute regime. A model-independent analysis was performed using the Porod invariant which defines the scale factor, leaving only the distribution of radii as the adjustable parameter. The presence of the PSS additive strongly retards the precipitation of CaCO3 NPs. The formation of NPs reaches a state of equilibrium after a few minutes. Here, it is shown that the concentration of precursors at a fixed PSS concentration plays a key role in determining the size of the NPs obtained. A full analysis of the SAXS patterns was carried out using the Hurd-Flower model to account for the weaker intensity decay than the classical Porod behaviour. The temporal evolution of the particle radii was determined. Wide-angle X-ray scattering experiments carried out simultaneously show that the particles formed have the structure of vaterite with growth consistent with the evolution of the Porod invariant.

Self-transformation of solid CaCO3 microspheres into core-shell and hollow hierarchical structures revealed by coherent X-ray diffraction imaging.

The self-transformation of solid microspheres into complex core-shell and hollow architectures cannot be explained by classical Ostwald ripening alone. Here, coherent X-ray diffraction imaging and 3D X-ray fluorescence were used to visualize in 3D the formation of hollow microparticles of calcium carbonate in the presence of polystyrene sulfonate (PSS). During the dissolution of the core made from 10-25 nm crystals, the shell developed a global spheroidal shape composed of an innermost layer of 30 nm particles containing high PSS content on which oriented vaterite crystals grew with their c axis mainly oriented along the meridians. The stabilizing role of PSS and the minimization of the intercrystal dipolar energy can explain in combination with Ostwald ripening the formation of these sophisticated structures as encountered in many systems such as ZnO, TiO2, Fe2O3, Co3O4, MnO2, Cu2O, ZnS, CaCO3 and Ca8H2(PO4)6·5H2O.

Microscopic Understanding of the Granular Structure and the Swelling of PEDOT:PSS

The conjugated polymer poly(3,4-ethylenedioxythiophene) polymerized and stabilized in the presence of polystyrenesulfonate (best known as PEDOT:PSS) is a working horse of organic electronics and bi...

Octahedral {Ta6I12} Clusters.

Ta powder reacts with I2 at 650 °C with the formation of Ta6I14, which belongs to the family of {M6(μ-X)12} clusters. It undergoes aquation with the formation of the intensely colored [Ta6I12(H2O)6]2+. The crystal structure was determined for [Ta6I12(H2O)6](BPh4)2·xH2O (Ta-Ta 2.9322(6) Å, Ta-I 2.8104(7) Å, Ta-O 2.3430(5) Å). With DMF, [Ta6I12(DMF)6]I2·xDMF was isolated (Ta-Ta 2.9500(2) Å, Ta-I 2.8310(4) Å, Ta-O 2.2880(7) Å). Cyclic voltammetry of [Ta6I12(H2O)6]2+ shows two consecutive quasi-reversible one-electron oxidations (E1/2 0.61 and 0.92 V vs Ag/AgCl). Reaction of Ta6I14 with Bu4NCN yields (Bu4N)4[Ta6I12(CN)6]·xCH3CN (Ta-Ta 2.9777(4) Å, Ta-I 2.8165(6) Å, Ta-C 2.2730(7) Å). Quantum chemical calculations reproduce well the experimental geometry of the aqua complex and show the essentially Ta-centered nature of both the HOMO and LUMO. The long-term stability of [Ta6I12(H2O)6]2+ solutions can be greatly enhanced in the presence of polystyrenesulfonate (PSS), which forms nanoparticle associates with the aqua complex in water (ca. 1 cluster per 3 PSS monomeric units).

Efficiency of a fungal laccase in 3,4-ethylenedioxythiophene polymerization

A high-redox potential laccase from fungus Trametes hirsuta was used as a biocatalyst to synthesize poly(3,4-ethylenedioxythiophene) (PEDOT), which is a promising material possessing both electronic and optical properties. This enzyme only requires molecular oxygen as an oxidant, which represents a great advantage for oxidative coupling reactions. The enzymatic oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) was performed using water-soluble sodium polystyrene sulfonate (PSS) as a template. The pH of the reaction medium and Zn2+ ions influenced the rate of EDOT polymerization. The water-dispersible PEDOT/PSS complex was characterized by UV–Vis and Fourier transformed infrared spectroscopy, as well as by transmission electron microscopy. Enzymatic EDOT polymerization was also carried out in the presence of PSS and multi-walled carbon nanotubes (MWCNT). The PEDOT/PSS/MWCNT composite had a conductivity of ca. 5.7 S/cm and specific electrochemical capacitance of ca. 246 F g−1, calculated from cyclic voltammograms at a potential scan rate of 5 mV s−1.

Plexcitons: The Role of Oscillator Strengths and Spectral Widths in Determining Strong Coupling.

Strong coupling interactions between plasmon and exciton-based excitations have been proposed to be useful in the design of optoelectronic systems. However, the role of various optical parameters dictating the plasmon-exciton (plexciton) interactions is less understood. Herein, we propose an inequality for achieving strong coupling between plasmons and excitons through appropriate variation of their oscillator strengths and spectral widths. These aspects are found to be consistent with experiments on two sets of free-standing plexcitonic systems obtained by (i) linking fluorescein isothiocyanate on Ag nanoparticles of varying sizes through silane coupling and (ii) electrostatic binding of cyanine dyes on polystyrenesulfonate-coated Au nanorods of varying aspect ratios. Being covalently linked on Ag nanoparticles, fluorescein isothiocyanate remains in monomeric state, and its high oscillator strength and narrow spectral width enable us to approach the strong coupling limit. In contrast, in the presence of polystyrenesulfonate, monomeric forms of cyanine dyes exist in equilibrium with their aggregates: Coupling is not observed for monomers and H-aggregates whose optical parameters are unfavorable. The large aggregation number, narrow spectral width, and extremely high oscillator strength of J-aggregates of cyanines permit effective delocalization of excitons along the linear assembly of chromophores, which in turn leads to efficient coupling with the plasmons. Further, the results obtained from experiments and theoretical models are jointly employed to describe the plexcitonic states, estimate the coupling strengths, and rationalize the dispersion curves. The experimental results and the theoretical analysis presented here portray a way forward to the rational design of plexcitonic systems attaining the strong coupling limits.

Improved oil recovery by reducing surfactant adsorption with polyelectrolyte in high saline brine

Abstract Surfactant adsorption on reservoir rock is one of the biggest challenges of chemical enhanced oil recovery (cEOR) techniques. This problem can become severe in high saline brine environments. In this work, the efficacy of a polyelectrolyte, polystyrene sulfonate (PSS), as a sacrificial agent for lowering surfactant adsorption from reservoir brine that has totally dissolved solids (TDS) of over 300,000 mg/l is investigated. Four different molecular weight PSSs are evaluated through equilibrium and dynamic adsorption studies carried out on Berea sandstone and Ottawa sand. Results show significant reduction in surfactant adsorption after PSSs addition. The effects of surfactant/PSS addition techniques, sequential and simultaneous, on surfactant and/or PSS adsorptions are also studied. Sand pack studies are conducted to evaluate the effect of PSS-minimized surfactant adsorption on oil mobilization/recovery. Results show substantial improvement in oil recovery in the presence of PSS, suggesting a potential as a sacrificial agent in cEOR.

Phosphomolybdate-doped-poly(3,4-ethylenedioxythiophene) coated gold nanoparticles: Synthesis, characterization and electrocatalytic reduction of bromate

Phosphomolybdate, H3PMo12O40, (PMo12)-doped-poly(3,4-ethylenedioxythiophene) (PEDOT) coated gold nanoparticles have been synthesized in aqueous solution by reduction of AuCl4− using hydroxymethyl EDOT as a reducing agent in the presence of polystyrene sulfonate and PMo12. The resulting PMo12-doped-PEDOT stabilized Au nanoparticles are water soluble and have been characterized by UV–visible spectroscopy, scanning electron microscopy and electrochemistry. Glassy carbon electrodes modified with these Au nanoparticles show excellent stability and catalytic activity towards the reduction of bromate in an aqueous electrolyte solution containing 10mM H2SO4 and 0.1M Na2SO4.

Synthesis of water-soluble conducting polypyrrole with transition-metal tetrasulfonated porphyrins

A novel catalytic route for the synthesis of a water-soluble and electrically conducting polypyrrole (PPy) in the presence of sulfonated polystyrene (SPS) is presented. Anionic water-soluble transition-metal tetrasulfonated porphyrins (TSPP) were used to catalyze the polymerization. The reactions were carried out with different monomer, catalyst, template and initiator concentrations and the optimum conditions are reported. Also various pH values ranging from 1 to 4 were investigated. The absorbance of the polaron bands at different pH values demonstrates that pH 2 is the best condition for polymerization. Precipitation or "salting out" phenomenon was highly dependent on the mentioned factors. The formation of PPy was confirmed by UV-vis and FT-IR spectroscopy. Cyclic voltammetry (CV) showed that the synthesized polymer has convenient electroactivity. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

Synthesis and characterization of poly(catechol) catalyzed by porphyrin and enzyme

Catalytic polymerization of catechol was performed employing the cationic porphyrin and horseradish peroxidase (HRP) as catalysts. The obtained results demonstrate that the cationic metalloporphyrin is a more-efficient catalyst than the HRP in the catechol polymerization. The oxidative polymerization was carried out in the presence of polystyrene sulfonate (PSS) as a template. According to TGA data, poly(catechol) that is synthesized by porphyrin catalyst exhibits more thermal stability than the enzymatic catalyzed product. The GPC indicate higher molecular weight of polymer synthesized by porphyrin as a catalyst. Cyclic voltammetry measurements show that the synthesized polymers have convenient electroactivity. The poly(catechol) and its methyl and methoxy derivatives that are synthesized by porphyrin catalyst show low electrical conductivity.

Preparation of the γ‐Al2O3/PANI nanocomposite via enzymatic polymerization

AbstractPeroxidase‐catalyzed template‐guided polymerization of aniline in the presence of γ‐ alumina nanosheet (NS) particles have been carried out in aqueous media and γ‐Al2O3/PANI nanocomposite was obtained. The polymerization of aniline occurred in aqueous solution in the presence of SPS (sulfonated polystyrene) as a template and SDS (sodium dodecyl sulfate) as a surfactant. Both obtained nanocomposites were comparable by SEM images. It was demonstrated that the γ‐Al2O3 NS/PANI‐SPS nanocomposite has higher conductivity and the γ‐Al2O3 NS/PANI‐SDS nanocomposite has higher void areas. The higher conductivity of γ‐Al2O3 NS/PANI‐SPS nanocomposite is attributed to the higher coated areas of γ‐Al2O3 NS during polymerization in comparison with γ‐Al2O3 NS/PANI‐SDS which are not coated efficiently as the former. The FT‐IR studies showed that the γ‐Al2O3 NS/PANI nanocomposite was formed by interaction of the polyaniline (PANI) and γ‐Al2O3 NS. FTIR also showed that the amount of PANI in γ‐Al2O3 NS/PANI‐SPS is more than in γ‐Al2O3 NS/PANI‐SDS. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

First Enzymatic Synthesis of Water-Soluble Conducting Poly(3,4-ethylenedioxythiophene)

The enzymatically catalyzed polymerization of 3,4-ethylenedioxythiophene in the presence of polystyrenesulfonate is introduced. This is the first time that an enzymatically catalyzed poly(3,4-ethylenedioxythiophene) (PEDOT) is reported. Horseradish peroxidase enzyme was used as a catalyst for the polymerization process leading to a water-soluble PEDOT that was characterized by UV-vis spectra, Fourier transform infrared, and electrical conductivity measurements. Water-soluble PEDOT showed excellent film formation ability as confirmed by atomic force microscopy images.

Destructive effect of polystyrene sulfonate on the structure of hemoproteins

The mechanism of the destruction of horse heart hemoglobin (Hb) and spermwhale muscle myoglobin (Mb), two hem-containing proteins, by polystyrene sulfonate, an anionic polyelectrolyte, was studied. Measurements of the optical absorption of the prostetic group of the hem in the visible spectrum and of the circular dichroism in the absorption bands of the peptide groups and aromatic amino acid residues demonstrated that the compact structure of both proteins experiences destruction in the presence of polystyrene sulfonate (PSS) at PSS concentrations ten times as low as that of the protein (in wt %) and that the content of α-helix structure in Hb and Mb decreases from 81% in the native state to 43% in their complexes with PSS. The distinctions in the mechanisms of the destruction of Hb and Mb by PSS were found to be as follows: (1) in contrast to Mb, Hb forms insoluble complexes with PSS at low PSS concentrations and (2) Mb-PSS solutions at Mb-to-PSS ratios >1 were found to contain free hems (that absorb at 397 nm), a feature not observed for Hb; the kinetics of the destruction of both the proteins by the polyelectrolyte was demonstrated to be a two-stage process. The first stage of the destruction of Hb (τ ≈ 24.5 s) was found to be four times as slow as that of Mb (τ ≈ 6 s); the second (slow) stage had a halftime of ∼6 h for both the proteins under study. To determine the localization of regions at the protein molecule surface that are capable of binding polyelectrolyte molecules, the distribution of the electrostatic potential over the surface of the Hb and Mb molecules was numerically calculated with the help of the Poisson-Boltzmann equation at pH 6.2 and an ionic strength of 100 mmol/l. Based on experimental and theoretical studies of the mechanism of the interaction of the polyelectrolyte with the proteins, the structural-functional properties of proteins responsible for their destruction by the polyelectrolyte are determined.

Calcite Mesocrystals: “Morphing” Crystals by a Polyelectrolyte

Crystallization of calcite from different concentrated calcium chloride solutions by the CO(2) vapor diffusion technique in the presence of polystyrenesulfonate (PSS) yields defined assemblies of nanoparticles with unusual morphology. From the typical calcite rhombohedra, the morphology can be systematically varied via rounded edges and truncated triangles to concavely bent lens-like shapes. Although these "crystals" are apparently well facetted as observed in light microscopy, electron microscopy analysis and BET isotherms reveal that the structures are highly porous and are composed of almost perfectly three-dimensionally aligned calcite nanocrystals, scaffolded to the final, partly curved structures. The formation of all mesostructures is discussed within the framework of a polymer-mediated structure-formation process, in which the polymer is acting in four different ways. The present model case also provides evidence for the importance of nonclassical mesoscopic processes in polymer-controlled crystallization in general.

Electrokinetic potential of kaolinite clay in the presence of polystyrene sulfonate

The determination of the electrokinetic potential of clay is very important in many applications. Therefore, this work was aimed at studying the effect of poly(4- sodium styrene sulfonate) on the electrokinetic potential and the sedimentation behavior of kaolinite clays at different pH values and/or in the presence of sodium or calcium chlorides. At pH values lower than the point of zero charge (PZC) of the kaolinite clay, the zeta potential of Na- or Ca-kaolinite in CaCl2 solutions was higher than that in NaCl solutions at the same concentration. Above the PZC, the zeta potential of Na- or Ca-kaolinite in NaCl solution was higher than that in CaCl2 at the same electrolyte concentration. These results reflect the ability of calcium cations to compress the double layer of the kaolinite clay better than sodium cations. Also, below the PZC and at low concentrations of poly(4-sodium styrene sulfonate), the zeta potential of the kaolinite clay suspensions had low value, while the sediment volumes had higher values. On the other hand, above the PZC at increasing polymer concentrations, the zeta potentials increased but the sediment volumes had lower values compared to those produced below the PZC. The data showed the zeta potential of Na-kaolinite suspensions are higher than Ca-kaolinite, producing lower sediment volumes of Na-kaolinite compared to Ca-kaolinite at the same concentrations of polymer and/or pHs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1705–1711, 2006

Photophysics of aggregated 9-methylthiacarbocyanine bound to polyanions

The photophysical properties of 3,3 ′-diethyl-9-methylthiacarbocyanine (DTC) were studied in the presence of polystyrene sulfonate (PSS), polyacrylic acid (PAA) and polymethacrylic acid (PMA). The absorption spectra reflect a monomer/dimer equilibrium in neat aqueous solution and a shift towards bound H-aggregates, bound dimers and bound monomers on increasing the ratio of polyanion residue to dye concentrations ( r). These equilibria also determine the photodeactivation modes of DTC. The fluorescence intensity is reduced, when dimers and aggregates are present and strongly enhanced for low dye loading ( r=10 4). In contrast, the quantum yield of intersystem crossing is enhanced for bound dimers ( r=10 3).

Smooth and rough spherical calcium carbonate particles

Several studies dealing with crystallization of calcium carbonate (CaCO3) on solid surface [1] or in solution [2] have shown that the morphology and the growth of the crystal may be affected by the presence of foreign compounds or additives. Almost all such additives, which are organic or inorganic in nature, prevent or reduce the rate of CaCO3 crystallization from supersaturated solutions. Such studies are useful for many industrial applications, such as the production at large-scale of spherical CaCO3 particles with uniform size, and in preventing the precipitation of calcium carbonate in steam boilers. Furthermore in the biological mineralization, the calcium containing salts are the major constituents of mollusk shells. In these mineralized tissues, precipitation of oriented aragonite and calcite CaCO3 forms occur within polymeric tissues matrices. Acidic protein [3] which are located at the surfaces of the matrix interact from the solution with the growing CaCO3 crystals and are responsible for both nucleation and inhibition of crystallization. In the present work crystallisation of calcium carbonate (CaCO3) from supersaturated solutions and in the presence of polystyrene sulfonate (PSS1) and/or polystyrene-polyethylene oxide (SE10-30) copolymer has been investigated. The polyelectrolyte (PSS1) purchased from Aldrich and the copolymer (SE10-30), have molecular weights values equal to, respectively, 7×104 and 4000. The polystyrene and the polyethylene blocks of the copolymer SE 10-30 have molecular weights equal to, respectively, 1000 and 3000, and the sample is the same as used elsewhere [4]. Supersaturated solutions for crystal growth experiments were prepared by rapid addition of equal volumes of sodium carbonate (Na2CO3) to calcium nitrate (Ca(NO3)2 4H2O) solutions. In the case of the additives, the polymers aqueous solutions of PSS1 and/or SE10-30 were first added to calcium nitrate solution and the mixtures were stirred for about 15 min prior the rapid addition of Na2CO3 solutions. The crystal growth experiments were made at ambient temperature in a water-jacketed Pyrex glass vessel of 300-ml capacity. The precipitated CaCO3 crystals were recovered by filtration and the dried crystals were gold coated in vacuum and examined by scanning electron microscope at magnifications from ×2000 to 30 000. The crystallization of the calcium carbonate in the presence of SE10-30 additive, Fig. 1, results into agglomerates of primary particles with a size of few microns and rhombohedral morphologies. In the presence of the PSS1, Fig. 2, we obtain CaCO3 crystal having smooth spherical shape. Rough spherical particles, Fig. 3, were obtained in the presence of the PSS1/SE1030 polymer-copolymer mixture. The CaCO3 crystal structures obtained by the X-ray analyses were calcite when the additive is the SE10-30 copolymer and vaterite in the presence of the PSS1. The crystal structure obtained in the presence of the mixture PSS1/SE10-30 was vaterite. Further, the measurements of the time dependence of the conductivity indicates that the polyelectrolyte PSS1 has a retarding while the copolymer SE10-30 has an