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Dye-sensitized solar cells (DSSCs) with a quasi-solid electrolyte, which are based on nanocomposites of the poly(ethylene glycol) dimethyl ether (PEGDME) oligomer with nanometer-sized spherelike and rodlike SiO2nanomaterials, exhibit a higher energy conversion efficiency than do those with a liquid electrolyte. SiO2nanorods were prepared using an electrospinning technique, and the structural effect of the SiO2nanomaterials in the electrolyte on the DSSC was studied. In the presence of the SiO2nanomaterials, the diffusion of the redox couple was enhanced, resulting in a higher photovoltaic performance. By changing the shape from sphere to rod, the photocurrent of the DSSC increased up to 12.0 mA cm–2, and a 38% increase in the cell efficiency under AM1 illumination at 100 mW cm–2with masking was observed. Since the recombination also increased with the addition of rodlike SiO2nanomaterials, generation 5, polyester-32-hydroxyl-1-carboxyl 2,2-bis(hydroxylmethyl)propionic acid dendrons terminated in carboxylic acid moieties were employed as coadsorbents to reduce the recombination; the photocurrent value for the DSSCs was determined to be 14.1 mA cm–2, and the power conversion efficiency increased by as much as 47% in the quasi-solid electrolyte DSSCs containing rodlike silica nanomaterials.

Inorganic/organic nanocomposite counter electrodes comprised of sheetlike CoS nanoparticles dispersed in polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene (CoS/PEDOT:PSS) offer a synergistic effect on catalytic performance toward the reduction of triiodide for dye-sensitized solar cells (DSSCs), yielding 5.4% power conversion efficiency, which is comparable to that of the conventional platinum counter electrode (6.1%). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry measurements revealed that the composite counter electrodes exhibited better catalytic activity, fostering rate of triiodide reduction, than that of pristine PEDOT: PSS electrode. The simple preparation of composite (CoS/PEDOT:PSS) electrode at low temperature with improved electrocatalytic properties are feasible to apply in flexible substrates, which is at most urgency for developing novel counter electrodes for lightweight flexible solar cells.

Tetracyanchinodimethan(TCNQ) auf Silbernanopartikeln (AgNPs) induziert hohe positive Oberflächenladungen, die einen Grenzflächendipol erzeugen, über den sich die Energieniveaus der AgNPs einstellen lassen (siehe Bild). Poly(vinylpyrrolidon)‐Membranen, die dispergierte AgNPs mit TCNQ enthalten, zeigen eine hohe Selektivität bei der Trennung gasförmiger Olefin‐Paraffin‐Gemische.

Calling the tune: High positive surface charges induced by tetracyanoquinodimethane (TCNQ) allow tuning of the energy levels of silver nanoparticles (AgNPs) through an interface dipole (see picture). Facilitated transport membranes containing AgNPs with TCNQ dispersed in poly(vinylpyrrolidone) show high mixed‐gas selectivity for the separation of olefin/paraffin mixtures.

Alkoxysilane solutions based on tetraethoxysilane (TEOS) have been widely used for the consolidation of decaying heritage stone surfaces. TEOS-based products polymerize within the porous structure of the decaying stone, significantly increasing the cohesion of the grains of stone components. However, they suffer from practical drawbacks, such as crack formation of the gel during the drying phase due to the developing capillary force and dense gel fractures left inside of the stone. In this study, a TEOS-based stone consolidant containing functional (3-glycidoxypropyl)trimethoxysilane (GPTMS) and polyhedral oligomeric silsesquioxane (POSS) has been prepared in order to reduce gel crack formation during the drying phase. The addition of nanometer-sized POSS and/or GPTMS having a flexible segment reduces the capillary force developed during solvent evaporation. The properties of the TEOS/GPTMS/POSS composite solutions were compared with those of commercial products (Wacker OH and Unil sandsteinfestiger OH 1:1). The gelation time was similar to that of commercial consolidants, and the TEOS/GPTMS/POSS solution was stable over a period of up to 6 months. The addition of POSS and GPTMS provided a crack-free gel, while the gel from the commercial consolidants exhibited cracks after drying. The surface hydrophobicity of the treated decayed granite increased with the addition of POSS and GPTMS, and it was higher than that of the commercial product, implying the possibility of POSS and GPTMS as barriers to the penetration of water. This result implies that the TEOS/GPTMS/POSS solution showed a high suitability for the consolidation of granite heritage.

Abstract: Silver polymer electrolyte membranes consisting of AgBF4 or AgCF3SO3 dissolved in poly(2-ethyl-2-oxazoline) (POZ) or poly(N-vinyl pyrrolidone) (PVP) have previously shown outstanding separation performance for propylene/propane mixtures. The ideal separation factor (i.e. pure gas selectivity) of propylene over propane reached 15,000, but the actual selectivity (i.e. mixed gas selectivity) was approximately 50. In this study, the origin of large difference between pure and mixed gas selectivities has been elucidated in terms of membrane plasticization by propylene molecules. The membrane plasticization was confirmed by the decrease of selectivity with increasing propylene concentration in the feed, resulting from the increase of both propylene and propane permeances. The decrease of glass transition temperature (T g) in silver polymer electrolytes upon the sorption of propylene also supported the membrane plasticization, determined by in situ high-pressure differential scanning calorimetry (HPDSC). Further analysis of configuration entropy model revealed that the interaction of propylene/silver ion in POZ/AgBF4 was approximately 2-fold stronger than that in POZ/AgCF3SO3, which is in good agreement with the results of propylene solubility and FT-IR spectra. [Copyright &y& Elsevier]

Three different approaches utilizing oligomers, termed the “oligomer approaches”, followed by in situ self-solidification, were applied successfully to prepare solid-state dye-sensitized solar cells. The oligomer approach employs (1) supramolecules containing quadruple hydrogen-bonding sites at both chain ends, (2) oligomer blends with high-molecular-weight polymers, and (3) nanocomposites of oligomer with SiO2nanoparticles. The overall energy conversion efficiency was as high as 4.5% at 1 sun condition, which may be primarily due to both the increased ionic conductivity and the better interfacial contact between the TiO2layer and the electrolyte due to the deep penetration of the small-sized liquid oligomer electrolyte. A threshold ionic conductivity of ∼1 × 10-4S cm-1was also observed, below which the ionic conductivity may play a key role in determining the photocurrent and the energy conversion efficiency. Above the threshold ionic conductivity, the ionic conductivity may play a less-important role and other factors such as the recombination of the electrons on the surface of the TiO2layer with I3-in the electrolyte and the charge-transfer resistance at the interface between the counter electrode and the electrolyte may be critical. The effect of chemical properties of the oligomer terminal groups was also investigated to determine that the methyl terminal group is the best among -OH, -NH2, and -COOH primarily due to the least amount of change in the flat band potential.

Polymer/silver‐ion π‐complex membranes consisting of poly(hexamethylenevinylene) (PHMV) and silver tetrafluoroborate exhibit unusually high separation performance for olefin/olefin and olefin/paraffin mixtures. The formation of π complexes between silver ions and unsaturated C&dbond;C bonds of PHMV has been confirmed with wide‐angle X‐ray scattering, differential scanning calorimetry, and X‐ray photoelectron spectroscopy. Fourier transform infrared and ultraviolet spectroscopy studies have revealed that silver ions make π complexes with olefins such as 1,3‐butadiene, propylene, and ethylene. Of these three olefins, 1,3‐butadiene has the highest binding affinity with silver ions in dissolved in PHMV, and this results in its higher solubility and permeance. Therefore, the π‐complex membranes exhibit unusually high separation performance for olefin/olefin and olefin/paraffin mixtures. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1434–1441, 2006

When polymer–silver salt complex membranes were exposed to UV irradiation, the separation performances of both the permeance and selectivity for propylene–propane decreased, which was primarily attributed to the reduction of the silver ions in the membranes to silver nanoparticles. Here, the effect of the polymer matrix on the formation of silver nanoparticles in the polymer–silver salt complex membranes was investigated. This effect was assessed for the complexes of two kinds of silver salts (AgBF4 and AgCF3SO3) with several polymeric ligands containing three different carbonyl groups, including poly(vinyl pyrrolidone) (PVP) with an amide group, poly(vinyl methyl ketone) (PVMK) with a ketone group, and poly(methyl methacrylate) (PMMA) with an ester group. UV–vis spectra and transmission electron microscopy (TEM) images clearly indicated that the reduction rate of the silver ions has the following order in the various polymer matrices: PVP > PVMK > PMMA, whereas the size and the distribution of the nanoparticles exhibited the reverse order. The tendency to form silver nanoparticles was explained in terms of the differences between the comparative strengths of the interactions of the silver ions with the different carbonyl oxygens in the matrices, as well as that of the silver ions with counteranions, which was characterized by X‐ray photoelectron spectroscopy (XPS) and FT‐Raman spectroscopy. It was concluded that when the concentration of free silver ions was low due to weak polymer–silver ion and strong silver ion–anion interactions, as found with PMMA, the reduction rate of silver ions to silver nanoparticles was slow. Therefore, the PMMA–silver complex membranes were less sensitive to decreases in separation performance upon UV irradiation than compared to the PVP membranes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1168–1178, 2006

The interaction of a phthalate group in poly(ethylene phthalate) (PEP) with silver ion has been elaborated in detail to understand the reduction behavior of silver ions to silver nanoparticles. Previously, the polymer electrolytes consisting of silver ions dissolved in PEP have shown highly stable separation performance for propylene/propane mixtures primarily due to the retardation of the reduction reaction of silver ions to silver nanoparticles, which is possible by means of the chelating bonds between phthalate groups and silver ions. Thus, in this study, the interaction was systematically investigated by both the theoretical ab initio calculation and the experimental Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The results show that the interaction of silver ion with phthalate group in PEP is approximately two times stronger than that with other functional groups such as amide, ketone, and ester in various polymers, in which the latter ones show the rapid reduction reaction and consequently lose their olefin carrier activity with time. Therefore, it is concluded that the reduction reaction of silver ions to silver nanoparticles is retarded remarkably in PEP/silver salts systems primarily because of the strong interaction between the phthalate group in PEP and silver ion, and consequently the formation of silver nanoparticles would be effectively prohibited, as confirmed by transmission electron microscopy and ultraviolet–visible spectroscopy. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3344–3350, 2004

π-Complexes of silver salts with polystyrene (PS) were prepared and tested in the separation of propylene/propane mixtures. After the incorporation of silver ions into the PS matrix, both the pure propylene gas permeance of the membrane and its olefin selectivity with respect to the propylene/propane mixtures were remarkably higher than those of the pure PS membrane, demonstrating facilitated propylene transport through the solid-state membrane. The remarkable separation performance of the PS/silver salt membranes was attributable to the unusually high solubility of the silver salts in the PS matrix, which was possibly due to the formation of π-complexes between the silver ion and aromatic C&dbond;C bond of PS. The coordination properties and dissolution behavior of the silver salts in PS were investigated with Fourier transform infrared, Fourier transform Raman, and X-ray photoelectron spectroscopy. The values for the intersegmental d-spacing, determined by wide-angle X-ray scattering, also showed that significant transient crosslinks arose between the PS chains when the silver salts were added to the PS matrix. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2263–2269, 2004

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The high selectivity of solid-state crosslinked poly(vinyl alcohol) (CPVA) membranes containing silver hexafluoroantimonate (AgSbF6), with respect to olefin/paraffin mixtures, was previously reported. The structure and coordination properties of CPVA/AgSbF6 complexes were investigated in this study with wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and theoretical ab initio calculations, and they were compared with those of poly(vinyl alcohol) (PVA)/AgSbF6 complexes. Contrary to expectations, the measurements of the intersegmental d-spacings and glass-transition temperatures indicated that the chain mobility in the PVA/AgSbF6 membranes was lower than that in the CPVA/AgSbF6 membranes. The different extents of transient crosslinking in the two systems were attributed mostly to their different coordination structures; silver ions in PVA/AgSbF6 were coordinated with hydroxyl oxygens located near the polymer main chains, whereas those in CPVA/AgSbF6 were coordinated with aldehyde oxygens located far from the main chains. According to WAXS spectra, AgSbF6 was completely dissolved in both PVA and CPVA, and this disrupted the crystallinity of the polymers. However, our DSC study showed that the silver ions dissolved in both polymer matrices recrystallized into silver oxide at elevated temperatures. The binding energy of Ag3d5/2, as determined from XPS spectra, shifted to lower values with the addition of increasing amounts of the polymer matrix, indicating the increasing coordination of silver ions with polymer chains. The presence of various oxygen species with and without coordination to silver ions was confirmed from O1s XPS spectra of CPVA membranes containing silver ions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 621–628, 2004

The difference between the polymer matrices of poly(2-ethyl-2-oxazoline) (POZ) and poly(N-vinyl pyrrolidone) (PVP) does not have a significant effect on the facilitated propylene transport and propylene solubility in 1:1 polymer/silver salt complex membranes, according to our previous work. In this article, its origin is investigated in terms of both microstructures of silver polymer electrolytes and the coordinative interaction of silver ion with polymer and with the counteranion. Initially different microstructures of POZ and PVP become similar to each other upon dissolving a large amount of silver salt, as evidenced by propane transport properties, specific volume, and Bragg d-spacing. The dissolution of the silver salt in the polymer solvent strongly depends on the coordinative interaction between silver ion and carbonyl oxygen of POZ and PVP. Thus, the structural similarity upon dissolving silver salts in POZ and PVP is primarily determined by the coordinative interaction between silver ion and carbonyl oxygen, which was confirmed by theoretical structure calculation based on density functional theory and by IR and Raman spectroscopy. Therefore, facilitated olefin transport for silver polymer electrolyte membranes does not strongly depend on the polymeric matrix at high silver concentrations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 232–237, 2004

Three methods to block the methanol transport through proton-conducting polymer membranes while maintaining the proton conductivity unchanged have been conducted; 1) selective layer formation on the surface of the membrane, 2) prearation of nanoclay composite membrane providing tortuous pathway of methanol, 3) control and fixation of the proton transport channels. The methanol permeability through the membranes decreased significantly at the expense of the small decrease in the proton conductivity. It is thus concluded that both the structure and the fixation of the proton transport channels are crucial in optimizinging proton conducting membranes for direct methanol fuel cells.

Three methods to block the methanol transport through proton‐conducting polymer membranes while maintaining the proton conductivity unchanged have been conducted; 1) selective layer formation on the surface of the membrane, 2) prearation of nanoclay composite membrane providing tortuous pathway of methanol, 3) control and fixation of the proton transport channels. The methanol permeability through the membranes decreased significantly at the expense of the small decrease in the proton conductivity. It is thus concluded that both the structure and the fixation of the proton transport channels are crucial in optimizinging proton conducting membranes for direct methanol fuel cells.

The commercial polyimide Matrimid was modified by bromination for the purpose of improving its membrane-transport properties as a gas-separation material and providing functional group reactivity for further modifications. The unmodified and brominated polymers were characterized by elemental analysis and one-dimensional and two-dimensional NMR, which revealed that one bromine atom per repeat unit was incorporated regioselectively onto the indane aromatic ring. The thermal and physical properties of the polymers before and after bromination were also investigated. The gas-transport properties of the unmodified and brominated polymers were compared. © 2002 Government of Canada. Exclusive worldwide publication rights in the article have been transferred to Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4193–4204, 2002

Silver salts are dissolved in poly(butyl methacrylate) to derive polymer electrolytes via coordinative interaction between the silver ion and the carbonyl oxygen atom. The dissolved silver ions react subsequently with propylene to form reversible silver/olefin complexes that can be utilized as olefin carriers for facilitated olefin transport. The complexation behavior and its effects on propylene transport were investigated by means of Raman and FT‐IR spectroscopy, as well as dielectric thermal analysis.

Interactions of cation/anion and cation/polymer in poly(N-vinyl pyrrolidone) (PVP):silver triflate (AgCF3SO3) electrolytes with different weight-average molecular weights (Mw's) of 1 × 10⁶ (1 M), 3.6 × 10⁵ (360 K), 4 × 10⁴ (40 K), and 1 × 10⁴ (10 K) have been studied with IR and Raman spectroscopies. According to the change of the C&dbond;O peak, coordination of silver ions by C&dbond;O in a low Mw (10 or 40 K) PVP matrix tend to be always thermodynamically favorable than high Mw (1 M or 360 K) PVP, demonstrating that the polymer matrix of low Mw dissolves silver salts more effectively. In addition, silver cations interact with both larger SO⁻3 and smaller CF3 to form ion pairs, and the former interaction is stronger than the latter in a monomer or low Mw polymer matrix (40 K, 10 K), as demonstrated by theoretical ab initio calculation or experimental spectroscopy, respectively. However, CF3 interacts more favorably with silver cation than SO⁻3 in high Mw (1 M and 360 K) PVP, which is ascribed to the steric effect of the bulky SO⁻3 anion by highly entangled polymer chains. Despite the superior dissolving property of the low Mw polymer matrix, the membranes consisting of low Mw PVP and AgCF3SO3 exhibited poor separation performance for propylene/propane mixtures in comparison with those of high Mw, presumably because of the poor mechanical property for membrane formation in low Mw PVP. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1813–1820, 2002

Interactions of cation/anion and cation/polymer in poly(N-vinyl pyrrolidone) (PVP):silver triflate (AgCF3SO3) electrolytes with different weight-average molecular weights (Mw's) of 1 × 10⁶ (1 M), 3.6 × 10⁵ (360 K), 4 × 10⁴ (40 K), and 1 × 10⁴ (10 K) have been studied with IR and Raman spectroscopies. According to the change of the C&dbond;O peak, coordination of silver ions by C&dbond;O in a low Mw (10 or 40 K) PVP matrix tend to be always thermodynamically favorable than high Mw (1 M or 360 K) PVP, demonstrating that the polymer matrix of low Mw dissolves silver salts more effectively. In addition, silver cations interact with both larger SO⁻3 and smaller CF3 to form ion pairs, and the former interaction is stronger than the latter in a monomer or low Mw polymer matrix (40 K, 10 K), as demonstrated by theoretical ab initio calculation or experimental spectroscopy, respectively. However, CF3 interacts more favorably with silver cation than SO⁻3 in high Mw (1 M and 360 K) PVP, which is ascribed to the steric effect of the bulky SO⁻3 anion by highly entangled polymer chains. Despite the superior dissolving property of the low Mw polymer matrix, the membranes consisting of low Mw PVP and AgCF3SO3 exhibited poor separation performance for propylene/propane mixtures in comparison with those of high Mw, presumably because of the poor mechanical property for membrane formation in low Mw PVP. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1813–1820, 2002

Interactions of cation/anion and cation/polymer in poly(N-vinyl pyrrolidone) (PVP):silver triflate (AgCF3SO3) electrolytes with different weight-average molecular weights (Mw's) of 1 × 10⁶ (1 M), 3.6 × 10⁵ (360 K), 4 × 10⁴ (40 K), and 1 × 10⁴ (10 K) have been studied with IR and Raman spectroscopies. According to the change of the C&dbond;O peak, coordination of silver ions by C&dbond;O in a low Mw (10 or 40 K) PVP matrix tend to be always thermodynamically favorable than high Mw (1 M or 360 K) PVP, demonstrating that the polymer matrix of low Mw dissolves silver salts more effectively. In addition, silver cations interact with both larger SO⁻3 and smaller CF3 to form ion pairs, and the former interaction is stronger than the latter in a monomer or low Mw polymer matrix (40 K, 10 K), as demonstrated by theoretical ab initio calculation or experimental spectroscopy, respectively. However, CF3 interacts more favorably with silver cation than SO⁻3 in high Mw (1 M and 360 K) PVP, which is ascribed to the steric effect of the bulky SO⁻3 anion by highly entangled polymer chains. Despite the superior dissolving property of the low Mw polymer matrix, the membranes consisting of low Mw PVP and AgCF3SO3 exhibited poor separation performance for propylene/propane mixtures in comparison with those of high Mw, presumably because of the poor mechanical property for membrane formation in low Mw PVP. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1813–1820, 2002

A thin layer of star-shaped poly(ethylene oxide) (PEO) (starPEO), on the polydimethylsiloxane (PDMS) membrane was prepared by a simple immobilization procedure. Photoreactive molecules were introduced on the surface of the polymeric support to achieve the formation of thin starPEO film from the materials having no functional groups. This novel technique enabled us to immobilize any kind of chemical, especially one that had no functional groups, and readily to control the amount of immobilization. The gas permeation properties of the starPEO-immobilized PDMS membranes were investigated for pure propane and propylene. The permeance of gases were found to decrease in the starPEO-immobilized PDMS membranes, although the ideal separation factors for propylene/propane were increased with the loading amount of silver ions, because of the facilitation action of silver ions in the immobilized PEO unit on the PDMS membranes, as propylene carriers. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 83: 2369–2373, 2002

Physical properties of poly(amic acid) (PAA) casting solutions in N-methyl-2-pyrrolidone (NMP) containing lithium chloride (LiCl) were characterized by viscometry and dynamic light scattering (DLS) and were related to the morphological properties of asymmetric membranes prepared from these solutions. At a fixed polymer concentration, the increase in viscosity of the PAA solutions with increasing LiCl content is mainly determined by the viscosity of the salt–solvent medium, implying that the LiCl–NMP interactions are stronger than those between LiCl and PAA. Because of the strong salt–solvent interactions, complexes between LiCl and NMP are formed. The complexes reduce the solvent power of NMP for PAA inducing polymer aggregation (clustering) and/or transient cross-links in the solutions. Dynamic light scattering results for salt-containing solutions at low PAA concentrations support the existence of these aggregations. Solutions without salt showed a single relaxation, but solutions with LiCl exhibit multiple relaxation modes; two diffusional modes of cooperative and aggregates, and one angle independent transient network mode. The polymer aggregates and transient cross-links form a gel-like structure in the casting solution film and hinder macrovoid formation during phase inversion, resulting in asymmetric membranes with a primarily sponge-like structure.

Remarkable separation performance of olefin/paraffin mixtures was previously reported by facilitated olefin transport through silver-based polymer electrolyte membranes. The mechanism of facilitated olefin transport in solid membranes of AgCF3SO3 dissolved in poly(N-vinyl pyrrolidone) (PVP) is investigated. In silver polymer electrolyte membranes, only free anions are present up to the 2:1 mole ratio of [C=O]:[Ag], and ion pairs start to form at a ratio of 1:1, followed by higher-order ionic aggregates above a ratio of 1:2. At silver concentrations above 3:1, the propylene permeance increases almost linearly with the total silver concentration, unexpectedly, regardless of the silver ionic constituents. It was also found that all the silver constituents, including ion pairs and higher order ionic aggregates, were completely redissolved into free anions under the propylene environment; this suggests that propylene can be a good ligand for the silver cation. From these experimental findings, a new mechanism for the complexation reaction between propylenes and silver salts in silver–polymer electrolytes was proposed. The new mechanism is consistent with the linearity between the propylene permeance and the total silver concentration regardless of the kind of the silver constituents. Therefore, the facilitated propylene transport through silver–polymer electrolytes may be associated mainly with the silver cation weakly coordinated with both carbonyl oxygen atoms and propylene.

Remarkable separation performance of olefin/paraffin mixtures was previously reported by facilitated olefin transport through silver‐based polymer electrolyte membranes. The mechanism of facilitated olefin transport in solid membranes of AgCF3SO3dissolved in poly(N‐vinyl pyrrolidone) (PVP) is investigated. In silver polymer electrolyte membranes, only free anions are present up to the 2:1 mole ratio of [C=O]:[Ag], and ion pairs start to form at a ratio of 1:1, followed by higher‐order ionic aggregates above a ratio of 1:2. At silver concentrations above 3:1, the propylene permeance increases almost linearly with the total silver concentration, unexpectedly, regardless of the silver ionic constituents. It was also found that all the silver constituents, including ion pairs and higher order ionic aggregates, were completely redissolved into free anions under the propylene environment; this suggests that propylene can be a good ligand for the silver cation. From these experimental findings, a new mechanism for the complexation reaction between propylenes and silver salts in silver–polymer electrolytes was proposed. The new mechanism is consistent with the linearity between the propylene permeance and the total silver concentration regardless of the kind of the silver constituents. Therefore, the facilitated propylene transport through silver–polymer electrolytes may be associated mainly with the silver cation weakly coordinated with both carbonyl oxygen atoms and propylene.

The solubility gaps for poly(vinyl pyrrolidone) (PVP) in four polyimide solutions (NMP, DMF, GBL, DMSO) were determined by cloud point measurement and correlated with χPI/Solvent and ΔδPVP/Solvent. Membranes prepared with NMP and DMF systems showed a tendency of suppressing fingerlike structure with addition of PVP. On the other hand, membranes prepared with GBL and DMSO systems showed an inclination toward inducing macrovoid formation. These effects of PVP on the membrane morphology were explained by means of miscibility gap, viscosity of the polymer solution, polymer–polymer phase separation, and overall porosity. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3481–3488, 2001

We previously conducted a detailed study of gas-transport and other properties of a series of silicon derivatives of Udel polysulfone (PSf) and Radel polyphenylsulfone; we now report the details of their preparation by the reaction of lithiated polymer intermediates with chlorosilylalkylaryl electrophiles. Ortho-sulfone-substituted polymers with pendant trimethylsilyl, dimethylphenylsilyl, and diphenylmethylsilyl and other groups were obtained by direct metalation followed by the reaction of the dilithiated intermediate with the appropriate silyl electrophile. In addition, the structural regularity and geometry of the dilithiated site was also exploited to introduce silicon into the main chain by the reaction of dichlorosilyl electrophiles, leading to the formation of a new tricyclic heteroatom ring. Ortho-ether PSf derivatives were obtained from a dibrominated polymer via the lithiation of brominated polymer and reaction with a silyl electrophile. The degree of substitution of the silyl groups was 2.0 or less from dilithiated polymers and was dependent on the electrophile reactivity and reaction conditions. A detailed structural characterization of the polymers by NMR and IR spectroscopy is reported in addition to glass-transition temperatures and thermal stabilities. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2103–2124, 2001

The formation and physicochemical properties of polymer electrolytes strongly depend on the lattice energy of metal salts. An indirect but efficient way to estimate the lattice energy through the relationship between the heterolytic bond dissociation and lattice energies is proposed in this work. The heterolytic bond dissociation energies for alkali metal compounds were calculated theoretically using the Density Functional Theory (DFT) of B3LYP level with 6‐311+G(d,p) and 6‐311+G(2df,p) basis sets. For transition metal compounds, the same method was employed except for using the effective core potential (ECP) of LANL2DZ and SDD on transition metals for 6‐311+G(d,p) and 6‐311+G(2df,p) calculations, respectively. The dissociation energies calculated by 6‐311+G(2df,p) basis set combined with SDD basis set were better correlated with the experimental values with average error of ca. ±1.0% than those by 6‐311+G* combined with the LANL2DZ basis set. The relationship between dissociation and lattice energies was found to be fairly linear (r>0.98). Thus, this method can be used to estimate the lattice energy of an unknown ionic compound with reasonably high accuracy. We also found that the dissociation energies of transition metal salts were relatively larger than those of alkaline metal salts for comparable ionic radii. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 827–834, 2001

The surface carbonization of polyimide (PI) and polysulfone (PSf) by ion beam has been performed to adapt the carbon molecular sieve properties on the skin of the polymeric membranes without the deformation of the membrane structure. In order to control the structure of membrane skin and to improve gas transport properties, the irradiation conditions, such as the dosage and the source of ion beams, have been varied. The ideal separation factor of CO2 over N2 through the surface-modified PI and PSf membranes increased threefold compared to those of the untreated, pristine membranes, whereas the permeability decreased with almost two orders of magnitude. This appears to be due to the fact that the structure of membrane skin has been changed to a barrier layer. The formation of barrier layer was confirmed by comparing the calculated values of a simple resistance model with the experimental results, and the estimated permeability of this barrier was 10⁻⁴ barrer. It was concluded that ion beam irradiation could provide a useful tool for improving selectivity for gas separation membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1554–1560, 2000

The ionic conductivity of polymer electrolytes and their interfacial contact with dye-attached TiO2particles were enhanced markedly by the addition of amorphous oligomer into polymer electrolytes, resulting in very high overall energy conversion efficiency.

The effect of terminal groups of oligomer electrolytes on the photovoltaic performance of dye-sensitized solar cells DSSCs have been systematically investigated to show that the terminal group plays a critical role in determining the concentration of I3−, ionic conductivity, flatband potential and consequently the energy conversion efficiency.

We report remarkably high energy conversion efficiency 4.5 at 100 mW cm−2 of a dye-sensitized solar cell in the solid state, using composite polymer electrolytes containing fumed silica nanoparticles.

We report remarkably high energy conversion efficiency (4.5% at 100 mW cm−2) of a dye-sensitized solar cell in the solid state, using composite polymer electrolytes containing fumed silica nanoparticles.

Silver ions dissolved in a polymer matrix are additionally coordinated by carbonyl oxygens of asparagines and their counter anions interact with cationic sites, resulting in the enhanced activity of the silver ion as an olefin carrier for facilitated olefin transport.

The most effective ligand among –OH, –O– and –CHO for facilitated olefin transport by silver ions in room temperature crosslinked poly(vinyl alcohol) membrane has been evaluated.