Poly Vinylsulfonic Acid Research Articles

Influence of chitosan grafted poly(vinyl sulfonic acid) as template on the calcium carbonate crystallization

Chitosan was grafted with polyvinylsulfonic acid (CHI-graft-PVS) through either chemical activation (CA) or ultrasound radiation (US) methods and the percentages of grafting (%G), grafting efficiency (%E) and the average degree of polymerization (R) were determined. The effect of CHI-graft-PVS as templates for in vitro crystallization of CaCO3 was evaluated by using gas diffusion method at different pH. It was found that CHI-graft-PVS act as an efficient modifier of crystal morphology or inhibit the crystallization depending on the experimental media and the method of grafting used. SEM analysis revealed that CHI-graft-PVS obtained through US method act as an inhibitor for CaCO3 crystallization. When CHI-graft-PVS from CA method was used, SEM analysis showed different CaCO3 morphologies such as spherical, prismatic, biconcave and needle-like crystals. Additionally, EDS confirmed the presence of S atoms from CHI-graft-PVS adsorbed on the surface of CaCO3 crystals. Results indicated that CHI-graft-PVS controls the nucleation, polymorphs and morphology of CaCO3 crystals. The composition of this new template and the control of pH of the mineralization solution seem to be crucial during CaCO3 crystallization. CHI-graft-PVS template represents an alternative approach for understanding the biomineralization process and offers a wide range of possibility for polymer controlled crystallization.

An efficient, high yielding, and eco-friendly method for the synthesis of 14-aryl- or 14-alkyl-14H-dibenzo[a,j]xanthenes using polyvinylsulfonic acid as a recyclable Brønsted acid catalyst

Aryl or alkyl-14H-dibenzo[a,j]xanthene derivatives were synthesized efficiently by the reaction of 2-naphthol and aromatic or aliphatic aldehydes in the presence of polyvinylsulfonic acid (PVSA) as a reusable Bronsted acid catalyst under aqueous conditions at 90 °C. This reaction was studied under different conditions, and several solvents were examined. In terms of reaction yield and time, water was found to be the optimum solvent. The catalytic performance of PVSA was then compared with various acidic catalysts under optimized reaction conditions. The catalyst is well characterized using IR and DSC techniques.

Polyvinylsulfonic acid as a novel Brønsted acid catalyst for the synthesis of bis(indolyl)methanes

Polyvinylsulfonic acid as a novel, biodegradable, and efficient Brønsted acid catalyst for the reaction of indoles with aldehydes to obtain bis(indolyl)methanes has been reported. The catalyst exhibited remarkable activity, recyclability, and tolerated a wide variety of functional groups providing the desired bis(indolyl)methanes in excellent yield (64–96%) at room temperature using ethanol as a solvent. The effect of different reaction parameters like solvent, temperature, catalyst doses, and recyclability were investigated for the title reaction.

Modulation of the interfacial electrochemistry of surfactant-functionalised polypyrrole chemical sensor systems

The redox properties of electro-polymerized polypyrrole (Ppy) doped with different surfactants were studied in acid medium. It was found out that the addition of different surfactants affect the redox properties as evidenced by diffusion coefficients and rate constants calculated from experimental data obtained from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Three different surfactants were incorporated into polypyrrole matrix to form homogeneous composites i.e. anionic surfactant polyvinylsulphonic acid (PVSA) as well as non-ionic surfactants (polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton-X 100) and polyoxyethylene (20) sorbitan monolaurate (Tween 20). CV and EIS experiments were carried in the presence of the redox probe K3[Fe(CN)6]. Diffusion coefficient was interpreted as a measure of electron movement within the composite polymer structure and rate constant was interpreted as a measure of the rate of oxidation and reduction of the redox probe. The highest value for diffusion coefficient and rate constant was obtained for Ppy/PVSA as 8.16×10−12cm2s−1 and 1.05×10−5cms−1 respectively. The values obtained by CV and EIS were in good agreement.

SEC Assay for Polyvinylsulfonic Impurities in 2-(N-Morpholino)ethanesulfonic Acid Using a Charged Aerosol Detector

A quantitative method for measuring polyvinylsulfonic acid (PVS) concentrations in 2-(N-morpholino)ethanesulfonic acid (MES) is described here. Utilizing a TSK-GEL G2500PWxl SEC column, PVS elutes in the void volume as a sharp peak, yielding group separation between PVS and MES. 20 mM formic acid is used as the mobile phase, as its volatility is compatible with a charged aerosol detector. The low pH mobile phase also suppresses residual negative charges on the stationary phase, reducing the ion exclusion effect commonly observed in aqueous SEC. This method was qualified to measure PVS concentration in MES per International Conference on Harmonization guidelines, using multiple MES lots and other Good’s buffers such as N-(2-acetamido)-2-aminoethanesulfonic acid and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid.

Synthesis and Characterization of POA-PVS-DBS, POA-PVS-pTS, POA-pTS-DBS Co-Dopants Composite Films: A Comparative Study

In the present study, the composite films of poly(o-anisidine)–polyvinyl sulphonic acid–dodecyl benzene sulphonic acid (POA-PVS-DBS), poly(o-anisidine)–polyvinyl sulphonic acid–toluene sulphonic acid (POA-PVS-pTS), and poly(o-anisidine)–toluene sulphonic acid–dodecyl benzene sulphonic acid (POA-pTS-DBS) were synthesized on platinum electrode, using electrochemical polymerization. The POA-PVS-DBS, POA-PVS-pTS, and POA-pTS-DBS composite films were synthesized with 0.2 M o-anisidine, 0.4:0.1 M (PVS-DBS), 0.4:0.1 M (PVS-pTS), and 0.4:0.1 M (pTS-DBS) co-dopants, 1.0 pH and 1 mA/Cm2 applied current density at 27°C temperature, respectively. These synthesized films were characterized by using an electrochemical technique, conductivity measurement, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optimal film growth was achieved for synthesis of the POA film in the presence of polyvinyl sulphonic acid–dodecyl benzene sulphonic acid (PVS-DBS). The POA-PVS-DBS composite film exhibits good electrochemical properties, and high conductivity with uniform and porous surface morphology which can be used for the immobilization of bio-component.

Polyvinylsulfonic acid as a novel Brønsted acid catalyst for Michael addition of indoles to α,β-unsaturated ketones

Abstract Polyvinylsulfonic acid as a novel Bronsted acid catalyst has been reported for the Michael addition reaction of indoles to α,β-unsaturated ketones. This catalyst works as a homogeneous Bronsted acid catalyst giving excellent yields of β-indolylketones. The catalytic performance of polyvinylsulfonic acid was then compared with various acidic catalysts under optimized reaction condition and it was found to give better yield of required β-indolylketones. The catalyst is well characterized using IR, XRD and DSC techniques.

Selective antibody precipitation using polyelectrolytes: A novel approach to the purification of monoclonal antibodies

We evaluated the potential for polyelectrolyte induced precipitation of antibodies to replace traditional chromatography purification. We investigated the impact of solution pH, solution ionic strength and polyelectrolyte molecular weight on the degree of precipitation using the anionic polyelectrolytes polyvinylsulfonic acid (PVS), polyacrylic acid (PAA), and polystyrenesulfonic acid (PSS). As we approached the pI of the antibody, charge neutralization of the antibody reduced the antibody-polyelectrolyte interaction, reducing antibody precipitation. At a given pH, increasing solution ionic strength prevented the ionic interaction between the polyelectrolyte and the antibody, reducing antibody precipitation. With increasing pH of precipitation, there was an increase in impurity clearance. Increasing polyelectrolyte molecular weight allowed the precipitation to be performed under conditions of higher ionic strength. PVS was selected as the preferred polyelectrolyte based on step yield following resolubilization, purification performance, as well as the nature of the precipitate. We evaluated PVS precipitation as a replacement for the initial capture step, as well as an intermediate polishing step in the purification of a humanized monoclonal antibody. PVS precipitation separated the antibody from host cell impurities such as host cell proteins (HCP) and DNA, process impurities such as leached protein A, insulin and gentamicin, as well as antibody fragments and aggregates. PVS was subsequently removed from antibody pools to < 1 microg/mg using anion exchange chromatography. PVS precipitation did not impact the biological activity of the resolubilized antibody.

Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

The preserved activity of immobilized biomolecules in layer-by-layer (LbL) films can be exploited in various applications, including biosensing. In this study, cholesterol oxidase (COX) layers were alternated with layers of poly(allylamine hydrochloride) (PAH) in LbL films whose morphology was investigated with atomic force microscopy (AFM). The adsorption kinetics of COX layers comprised two regimes, a fast, first-order kinetics process followed by a slow process fitted with a Johnson–Mehl–Avrami (JMA) function, with exponent ~ 2 characteristic of aggregates growing as disks. The concept based on the use of sensor arrays to increase sensitivity, widely employed in electronic tongues, was extended to biosensing with impedance spectroscopy measurements. Using three sensing units, made of LbL films of PAH/COX and PAH/PVS (polyvinyl sulfonic acid) and a bare gold interdigitated electrode, we were able to detect cholesterol in aqueous solutions down to the 10 − 6 M level. This high sensitivity is attributed to the molecular-recognition interaction between COX and cholesterol, and opens the way for clinical tests to be made with low cost, fast experimental procedures.

Electrochemical Synthesis and Characterization of Poly(o-anisidine) Film with Various Dopants: A Comparative Study

In the present work, the doped (composite) films of póly(o-anisidine)–polyvinylsulphonic acid (POA-PVS), poly(o-anisidine)–toluenesulphonic acid (POA-pTS), and poly(o-anisidine)–dodecylbenzenesulphonic acid (POA-DBS) were synthesized on a platinum electrode, using electrochemical polymerization. These synthesized films were characterized by electrochemical techniques, conductivity measurement, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optimal film growth was achieved for synthesis of the POA film in the presence of dodecylbenzenesulphonic acid (DBS). The POA-DBS composite film exhibits good electrochemical properties, conductivity with a uniformly porous surface morphology which can be used for the immobilization of biocomponent.

Hydration of Nafion and Dowex in liquid and vapor environment: Schroeder's paradox and microstructure

Functioning of ion-exchange resins and ionomers strongly depends the state of hydration (equilibrium water uptake), which strongly affects their performance. The relation between water activity and uptake by such polymers (isotherm) has usually been measured by equilibration with water vapor of known activity. However, at the point of saturation (pure water) hydration by liquid water and water vapor differ, i.e., depend on the mode of equilibration. This effect, known as Schroeder's paradox, leads to an ambiguity in determination of the chemical potential and calculating the solvent transport in such systems. In order to verify the general nature of this phenomenon, we carried out a systematic examination of the paradox in a wide range of water activities using solutions of a polyelectrolyte (polyvinylsulfonic acid salts) as an osmotic stressor. This allowed measuring hydration isotherms in parallel vapor- and liquid-equilibration modes for two solid polymer electrolytes: Dowex (a cross-linked resin) and Nafion (an ionomer). The results indicate that for the studied polymers Schroeder's paradox extends to the whole range of the examined water activities. Furthermore, the difference between the isotherms could be related to the polymer microstructure, however, it suggested that a correction due to the difference between the surface and bulk microstructure is necessary for Nafion.

Optimization and use of composite coatings based on silicon oxide and polyvinylsulfonic acid for the adsorption-spectrophotometric determination of iron(II) and zinc(II) phenanthrolinates

Conditions are optimized for preparing sol-gel modified composite films based on silicon oxide and polyvinylsulfonic acid in the presence of the Tween 20 nonionic surfactant as a template for the adsorption of Fe(II) and Zn(II) phenanthrolinates. The adsorption of Zn(II), Cu(II), Mn(II), Co(II), and Ni(II) phenanthrolinates followed by their development on the surface with Rose Bengal oxyxanthene dye was studied by spectrophotometry. The variation of the pH of the solution pH and the addition of 0.01 M of EDTA enhanced the selectivity of determining Zn(II) using a film obtained under optimum conditions. The applicability of the proposed thin-film coatings to the adsorption-spectrophotometric determination of Fe(II) and Zn(II) in the ranges of 0.2–5.6 and 0.3–5.0 mg/L, respectively, was shown. The procedure was used to determine zinc in vitamin preparations, a food supplement, and an insulin preparation. The accuracy of determination was checked by atomic absorption spectrometry. The detection limit for zinc was 0.06 mg/L at a liquid phase volume of 25 mL and absorption layer thickness of 0.015 ± 0.003 mm.

All-solid-supercapacitor based on polyaniline and sulfonated polymers

All-solid-supercapacitor based on chemically synthesized polyaniline (PANI) and sulfonated polymers have been reported. Poly vinyl sulfonic acid (PVSA) is used as a proton conducting solid electrolyte. Fluorinated ethylene propylene copolymer grafted with acrylic acid and sulfonated (FEP-g-AA-SO 3H) membrane was used as the separator. Composite electrodes were prepared from PANI, PVSA, electronically conducing carbon and poly tetra fluroethylene (PTFE) powder. Electrochemical studies of the supercapacitor were carried out in a unit cell. The unit cell consisted of three layers structure: composite electrode//FEP-g-AA-SO 3H//composite electrode. This symmetric configuration of supercapacitor represents type1 (p-p) class, since both the electrodes were made from p-dopable PANI based composite electrodes. Optimization of solid electrolyte in the composite electrode was carried out. Supercapacitor was characterized by cyclic voltammetry and charge–discharge cycles. Capacitance of 98 F/g of PANI was obtained. The reduction in the capacitance after 1500 cycles was found to less than 20%. The non-ideal behavior of the supercapacitor was analyzed by impedance analysis.

Potentiometric study of polyaniline film synthesized with various dopants and composite-dopant: A comparative study

The potentiometric study of polyaniline (PANI) film synthesized with dopants viz. polyvinyl sulfonic acid (PVS),p-toluene sulfonic acid (p TS), dodecyl benzene sulfonic acid (DBS) and composite-dopants viz. PVS-p TS and PVS-DBS, has been carried out. The synthesized PANI films were characterized by electrochemical technique, UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and conductivity measurement. It was found that the PANI doped with PVS gives good electrochemical properties, conductivity as well as surface morphology as compared to p TS and DBS, whereas in composite dopants the PANI doped with PVS-pTS gives good polymer matrix as compared to PVS-DBS.

Galvanostatic deposition of Poly( N-methylpyrrole) film with various dopants and co-dopants: A comparative study

Synthesis of Poly( N-methylpyrrole) (P(NMP)) film with various dopants viz. PolyVinyl Sulphonic acid (PVS), p-Toluene Sulphonic acid (pTS), Sodium Nitrate (NaNO 3) has been studied by using galvanostatic deposition method. This is a comparative study of influence of above dopants on the synthesis of P(NMP) film using electrochemical studies, conductivity measurements, FTIR spectral studies and SEM. The optimal film growth was achieved for synthesis of the P(NMP) film in the presence of PVS. The influence of co-dopants i.e. PolyVinyl Sulphonic acid/ p-Toluene Sulphonic acid (PVS/pTS) and PolyVinyl Sulphonic acid/sodium nitrate (PVS/NaNO 3) on galvanostatic deposition of P(NMP) film has also been studied. This study reveals that the synthesized P(NMP) film with dopant PVS and co-dopant PVS/NaNO 3 provides good polymer matrix for immobilization of biocomponent.

Layer-by-Layer Surface Modification and Patterned Electrostatic Deposition of Quantum Dots

Modification of ZnS-capped CdSe quantum dot (QD) surfaces with polyelectrolyte coatings and subsequent layer-by-layer deposition to build hierarchical structures are presented. Mercaptoacetic acid (MAA)-treated QDs were sequentially coated with polyallylamine (PAA) and polyvinylsulfonic acid (PVSA) and analyzed using zeta potentials, absorbance spectra, and transmission electron microscopy. The modified QDs were deposited on patterned hyaluronic acid (HA) glass substrates to produce self-assembled heterostructures (QDs-MAA/QDs-PAA/HA/glass), as revealed by fluorescence and atomic force microscopy.

Mixed-mode electrokinetic chromatography of aromatic bases with two pseudo-stationary phases and pH control

The electrokinetic chromatographic (EKC) separation of a series of aromatic bases was achieved utilising an electrolyte system comprising an anionic soluble polymer (polyvinylsulfonic acid, PVS) and a neutral β-cyclodextrin (β-CD) as pseudo-stationary phases. The separation mechanism was based on a combination of electrophoresis, ion-exchange interactions with PVS, and hydrophobic interactions with β-CD. The extent of each chromatographic interaction was independently variable, allowing for control of the separation selectivity of the system. The ion-exchange and the hydrophobic interactions could be varied by changing the PVS and the β-CD concentrations, respectively. Additionally, mobilities of the bases could be controlled by varying pH, due to their large range of p K a values. The separation system was very robust with reproducibility of migration times being <2% RSD. The two-dimensional parameter space defined by the two variables, [β-CD] and %PVS, was modelled using a physical model derived from first principles. This model gave very good correlation between predicted and observed mobilities ( r 2=0.999) for the 13 aromatic bases and parameters derived from the model agreed with the expected ion-exchange and hydrophobic character of each analyte. The complexity of the mathematical model was increased to include pH and this three-dimensional system was modelled successfully using an artificial neural network (ANN). Optimisation of both the two-dimensional and three-dimensional systems was achieved using the normalised resolution product and minimum resolution criteria. An example of using the ANN to predict conditions needed to obtain a separation with a desired migration order between two of the analytes is also shown.

Ultramicroelectrode Arrays Modified with Ionomer-Entrapped Silica Films as Potential Voltammetric Sensors for Copper, Lead and Selenium

Composite silica-polyelectrolyte thin films obtained by the sol-gel technique were used as surface modifiers for gold-based ultramicroelectrodes (UME) and gold and iridium based UME arrays (UMEA). Poly(dimethyldiallylammonium chloride) (PDMDAAC) and polyvinylsulfonic acid (PVSA) were used as po lyelectrolytes. The best response for the electrodes modified with a composite film was observed for film thickness of 0.7 -0.9 μm and a polyelectrolyt e content of 1 -2 %. Silica-polyelectrolyte modified gold-based UMEs were shown to be useful for determining trace levels of copper (II) via CV with a detection limit of 5 ×10 -6 mol/L and for selenium(IV) by SWASV at 10 -9 mol/L levels. A mercury coated iridium -based UMEA covered with PVSA -silica composite film was used for lead (II) determination by SWASV. It was shown that silica-polyelectrolyte composite films increased selectivity for analyte determination and protected the surface of the electrodes from degradation and thus enhancing the life time of the electrode.

Heavy metals removal from wastewaters of phosphoric acid production: a comparison of hybrid liquid membrane (HLM) and aqueous hybrid liquid membrane (AHLM) technologies

Selective removal of heavy metal ions from industrial wet-process phosphoric acid (WPA) was studied, using the two liquid membrane systems: Hybrid Liquid Membrane (HLM) and Aqueous Hybrid Liquid Membrane (AHLM). Monothiophosphinic acid (Cyanex 302) in kerosene (for the HLM) and Polyvinylsulfonic acid (PVSA) aqueous solution (for the AHLM) were used as a liquid membrane (LM), separated from the feed and strip streams by neutral or cation-exchange membranes. On application of the HLM separation system, the permeation from the feed to the strip phase followed the selectivity sequence: Zn &amp;gt;&amp;gt; Cd &amp;gt; Cu with all types of membranes used. Results show that the selective separation of Cd and Zn from the WPA may be achieved by the HLM with cation-exchange membranes, using a single set-up installation at continuous processing. Copper is accumulated in the Cyanex 302, poisoning the carrier. So, this carrier and HCl as a strip solution can not be recommended for the HLM processing of WPA. Using the AHLM separation system, heavy metals such as cadmium and copper, were successfully recovered from the WPA: average fluxes (in mol/m2sec) to the strip phase were 3.7 × 10-7 and 6.7 × 10-7. Satisfactory dynamic selectivity to copper (≈16) was found. The transfer of iron and zinc species to the strip phase was below detection levels during the 144 hrs of the AHLM experiment. Contamination of the feed and strip solutions by PVSA was not observed during the 500 hrs of processing. The membranes were completely regenerable and used repeatedly. In comparison with the HLM and other liquid membrane systems, the AHLM can potentially provide many operational, economic and environmental advantages, some of them being higher transport rates, low carrier losses and low contamination of the feed and strip solutions by water-soluble polymers, long membrane lifetime, ambient temperature, low energy requirements and chemical consumption, no special requirements for membrane resistance in organic solvents, and fewer limitations on the variability of membrane pore sizes, etc.

Aqueous hybrid liquid membrane process for metal separation: Part II. Selectivity of metals separation from wet-process phosphoric acid

Selective separations of heavy metal ions from industrial wet-process phosphoric acid (WPA) were studied using an aqueous hybrid liquid membrane (AHLM) system. Polyvinylsulfonic acid (PVSA) aqueous solution was used as a liquid membrane (LM) phase, separated from the feed and strip streams by cation-exchange membranes. Heavy metals, such as cadmium and copper, were successfully recovered from the WPA: average fluxes (in mol/m 2 s) to the strip phase were 3.7 × 10 −7 and 6.7 × 10 −7, respectively, at a Cu/Cd selectivity of 2.7. The transfer of iron and zinc species to the strip phase was below detection levels during the 144 h of the AHLM experiment. Selectivity is not a constant parameter in the AHLM separation of metal ions. The idea of dynamic selectivity and techniques for its determination were introduced. Selectivity can be controlled by adjusting the concentration, volume and flow rate of the circulating bulk LM phase. Such a control of the selectivity is one of the advantages of the AHLM system in comparison with other LMs and Donnan dialysis technologies. A theoretical model has been developed for the simulation of the AHLM transport selectivity. Satisfactory correlation between experimental and simulated data was achieved. Selectivity parameters, needed for the AHLM module design, may be obtained by performing series of experiments with feed, carrier and strip flow rate variations, and of membrane-based extraction. Preliminary optimization of the AHLM module may be achieved by simulation of the feed- and strip-side membrane areas, concentrations and volumes of the bulk LM and strip phases, and flow rates.