Water‐mediated transport in ion‐containing polymers

Water‐mediated ion conduction enables high conductivity in hydrated polymer membranes commonly used in electrochemical devices. Understanding the coupling of the absorbed water with the polymer matrix and the dynamics of water inside the polymer network across the full range of length scales in the membrane is important for unraveling the structure–property relationships in these materials. By considering the water behavior in ion‐containing polymers, next‐generation fuel cell membranes are being designed that exceed the conductivity of the state‐of‐the‐art materials and have optimized conductivity and permeability that may be useful in other types of devices such as redox flow batteries. Water–polymer associations can be exploited to tune the transport and mechanical property tradeoffs in these polymers. Measurements of water motion provide important criteria for assessing the factors that control the performance of these types of materials. This review article discusses current understanding of water behavior in ion‐containing polymers and the relationship between water motion and ion and molecular transport. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Organosilicon ion‐exchange and complexing adsorbents

Literature data concerning research organosilicon ion‐exchangers and complexing agents have been summarized and systematized. Data on organophilic organosilicon adsorbents and sorption systems for chromatography are not considered here. Copyright © 1999 John Wiley & Sons, Ltd.     

Evaluation of antithrombogenicity of ion‐implanted silicone rubber

Ion implantations into silicone rods were performed at 150 keV with doses ranging from 1 × 10⁷ to 3 × 10¹⁷ ions/cm². The antithrombogenicity was tested by the superior vena cava (SVC) indwelling method for two days in rats with ¹¹¹In‐tropolone ‐ platelets, and by the inferior vena cava (IVC) indwelling method. Results of the SVC indwelling method showed that platelet accumulation on ion ‐ implanted specimens decreased. Macroscopic views of the ion‐implanted IVC specimens in dogs revealed little thrombus formation. In particular, SVC indwelling method revealed that O₂⁺, K⁺ and Kr⁺ (1 × 10¹⁷ ions/cm²) implantation was most effective in reducing platelet accumulation. Copyright © 1999 John Wiley & Sons, Ltd.     

Protein C recognition by ion‐coordinated imprinted monolithic cryogels

The protein C imprinted monolithic cryogel was synthesized using 2‐hydroxyethyl methacrylate by redox cryo‐polymerization method. The prepared monolithic cryogel was characterized by Fourier transform infrared spectroscopy, swelling test, surface area measurements, and scanning electron microscopy. The nonimprinted cryogel was prepared as well for control. Adsorption of protein C from aqueous solutions was investigated in a continuous mode and several parameters affecting adsorption performance were optimized. The maximum protein C adsorption amount was 30.4 mg/g. The selectivity studies were performed by monolithic column studies and fast protein liquid chromatography, using hemoglobin and human serum albumin as competing proteins. The relative selectivity coefficients were 2.37 and 8.89 for hemoglobin and human serum albumin, respectively. Reusability was tested for ten consecutive adsorption–desorption cycles, and no significant change in adsorption capacity was recorded. A pseudo‐second‐order model was suitable to interpret kinetic data, and the Langmuir model suited the adsorption isotherms well.     

Mesomorphic and conducting properties of dendritic‐linear copolymers via ion‐doped additives

We studied the conducting and mesomorphic behavior of a dendritic‐linear copolymer on adding hydrophilic additives and lithium salts. For the preparation of the pristine block copolymer ( A ), a click reaction of a hydrophobic Y‐shaped dendron block and a hydrophilic linear poly(ethylene oxide) coil with M_n = 750 g mol^?1 was performed. For ionic block copolymer samples ( 1–3 ), a hydrophilic compound ( B ) bearing two tri(ethylene oxide) chains was used as the additive. In all ionic samples, the lithium concentration per ethylene oxide was chosen to be 0.05. As characterized by polarized optical microscopy and small angle X‐ray scattering techniques, copolymer A showed a hexagonal columnar mesophase. On addition of lithium‐doped additives, ionic samples 1 and 2 with the additive weight fractions (f_w) of 10 and 20%, columnar and bicontinuous structures coexisted in the liquid crystalline phase. On the other hand, ionic sample 3 with f_w = 30% displayed only a bicontinuous cubic mesophase. Based on the impedance results, with increasing the amount of additives, the conductivity value increased from 3.80 × 10^?6 to 2.34 × 10^?5 S cm^?1 at 35 °C. The conductivity growth could be explained by the interplay of the plasticization effect of the mobile additive and the morphological transformation from 1D to 3D of the ion‐conducting cylindrical cores. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Performance evaluation of ion‐exchange chromatography in capillary format

The performance of a recently introduced capillary ion‐exchange chromatography system was explored. Experiments were conducted in isocratic mode with a commercial capillary anion‐exchange column (id = 0.4 mm, L = 15 cm) using a five‐anion standard mixture. The achieved results were compared to the performance of a standard bore ion‐exchange system (id = 4 mm, L = 15 cm), which was considered as a reference. The first‐generation capillary columns exhibited a minimal reduced plate‐height value below two witnessing a good packing quality and system performance. However, compared to the standard bore system the capillary system displayed an increased apparent C‐term which could be due to a difference in packing morphology and/or possible external band‐broadening contributions. For fast separations, the standard bore system outperformed the capillary system, while for complex separations both systems performed nearly equally well. In addition, the retention characteristics of the capillary system were investigated. To illustrate the suitability of the capillary system, the analysis of real‐world water samples originating from two local Belgian rivers was demonstrated.     

Damage‐depth profiling of ion‐irradiated polyimide films with a variable‐energy positron beam

Various polyimide layers [2.2–2.6 μm of hexafluoroisopropylidene bis(phthalic anhydride‐oxydianiline), pyromellitic dianhydride‐oxydianiline, and 3,3′‐4,4′‐biphenyltetracarboxylic dianhydride‐p‐phenylenediamine] spin‐coated on silicon substrates were studied with a variable‐energy positron beam in combination with a Doppler‐broadened annihilation radiation technique. From the experiments, the thickness of the layers was estimated with the VEPFIT routine. These values corresponded well to the values determined from interferometry and ellipsometry. Irradiation of the polyimides with 1 × 10¹⁵ boron ions/cm² at an energy of 180 keV led to a strong chemical modification of the irradiated top layer. This caused the inhibition of positronium formation in the irradiated layer, which was observed as a lowering of the annihilation line S parameter. The thickness of the modified layer was estimated to be 700–800 nm. This value did not agree with the ellipsometric measurements but corresponded to the maximum implantation depth of boron ions calculated with TRIM (Transport of Ions in Matter) code. The positron results appeared somewhat larger than the TRIM estimates. Reasons for these relations are discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 3062–3069, 2000     

Reversed‐phase ion‐pair high‐performance liquid chromatography assay of polyprenyl diphosphate oligomer homologues

A reversed‐phase ion‐pair high‐performance liquid chromatography procedure was developed for the separation of polyprenyl diphosphate oligomer homologues obtained chemically from plant polyprenols. Tetrabutylammonium phosphate was used as the ion‐pair reagent, and the dependence of the separation quality on pH of ion‐pair reagent was investigated for the first time. The procedure is applicable for the control of commercial available polyprenyl monophosphates (the active components of veterinary drugs Phosprenyl and Gamapren) for the possible presence of polyprenyl diphosphate byproducts.     

Syntheses and fluoride‐ion‐mediated hydrolysis of phosphoroselenoic acid ester and amides

Phosphoroselenoic acid ester and amides containing binaphthoxy moiety were prepared by reacting phosphoroselenoyl chloride with alcohols and secondary amines. The resulting amides underwent fluoride‐ion‐mediated hydrolysis with a THF solution of tetrabutylammonium fluoride to give two types of phosphoroselenoic acid ammonium salts: one with a fluorine atom and another with a binaphthoxy group on the phosphorus atom. The ratio of these products depended on the substituents on the nitrogen atom of the amides. A similar reaction of the ester with tetrabutylammonium fluoride gave two types of ammonium salts. The formation of these products was confirmed by converting them to the corresponding methyl esters. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:255–261, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20544     

Ionic size dependent electroosmosis in ion‐selective microchannels and nanochannels

Electrokinetics in salt‐free media (in which counterions are only present) is central to the performance of many systems of modern technological relevance, ranging from ion‐selective nanopores to electronic papers. Here, we introduce an analytical theory to describe the size dependence of electroosmosis in such typical scenarios, exhibiting an interesting confluence of the implications of interdependence of the electroosmotic transport mechanisms, ionic sizes, and confinement dimensions along with the counterion concentration. Our results do reveal that the concerned mobility parameter, describing the strength of electroosmotic transport, increases simultaneously with increments in the surface charge density as well as an ionic size factor (also known as the steric factor), bearing far‐ranging consequences in microfluidic and nanofluidic technology.     

Method development for separating organic carbonates by ion‐moderated high‐performance liquid chromatography

An ion‐moderated partition high‐performance liquid chromatography method was developed for the separation and identification of common organic carbonates. The separation of organic carbonates was achieved on an ion exclusion column with an exchangeable hydrogen ion. An isocratic, aqueous mobile phase was used for elution and detection was performed with a refractive index detector. The developed method was validated for specificity, linearity, limits of detection and quantification, precision and accuracy. All calibration curves showed excellent linear regression (R² > 0.9990) within the testing range. The limits of detection were 3.8–30.8 ppm for the analyzed carbonates. Improvements in the peak resolution of the chromatograms were achieved by decreasing the column temperature. Addition of the organic modifier, acetonitrile, to the eluent was found to have insignificant effects on the peak resolution. The developed method was demonstrated for analyzing organic carbonate components in the electrolyte system of a commercial lithium ion battery.     

Novel ion‐exchange resin beads with acid–base indicator property

Copolymers of styrene and methyl acrylate were synthesized in the form of spherical beads (0.4–1.2 mm) and sulfonated with concentrated sulfuric acid. The sulfonated copolymer shows an in‐built acid–base indicator property; the yellow color in the acid medium changes to an intense pink color at the equivalence point. Also, the ion‐exchange capacity of the sulfonated copolymer increases with time, reaches a maximum, and decreases thereafter. The results were explained in terms of Fourier transform infrared spectroscopic analysis considering internal Friedel–Craft acylation followed by cyclic dehydration leading to a conjugated structure. The developed ion‐exchange resin also demonstrated better performance in demineralization of water as compared with the conventional polystyrene‐based beads. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2166–2170, 2003     

Manipulating adenoviral vector ion‐exchange chromatography: Hexon versus fiber

The serotype specificity of adenovirus ion‐exchange chromatography has previously been studied using standard particle‐based columns, and the hexon protein has been reported to determine retention time. In this study, we have submitted Adenovirus type 5 recombinants to anion‐exchange chromatography using methacrylate monolithic supports. Our experiments with hexon‐modified adenoviral vectors show more precisely that the retention time is affected by the substitution of amino acids in hypervariable region 5, which lies within the hexon DE1 loop. By exploring the recombinants modified in the fiber protein, we have proven the previously predicted chromatographic potential of this surface constituent. Modifications that preserve the net charge of the hexon protein, or those that cause only a small charge difference in the fiber protein, in addition to shortening the fiber shaft, did not change the chromatographic behavior of the adenovirus particles. However, modifications that include the deletion of just two negatively charged amino acids in the hexon protein, or the introduction of a heterologous fiber protein, derived from another serotype, revealed recognizable changes in anion‐exchange chromatography. This could be useful in facilitating chromatography‐approach purification by creating targeted capsid modifications, thereby shifting adenovirus particles away from particular interfering substances present in the crude lysate.