Characteristics of dual‐type electrochromic devices based on poly(ethylene oxide) copolymers

Dual‐type polymer electrochromic devices based on [(3‐thienyl)methylmethacrylate]‐co‐[p‐vinyl benzyloxy poly(ethylene oxide)]/polythiophene and thiophene‐capped poly(ethylene oxide)/polythiophene and ethylene dioxythiophene were constructed via electropolymerization. Spectroelectrochemistry, switching ability and stability of the devices were investigated using UV‐visible spectrophotometry and cyclic voltammetry. These devices exhibit low switching voltages and short switching times with reasonable switching stability under atmospheric conditions. Copyright © 2006 Society of Chemical Industry     

Crystallinity,thermal properties,morphology and conductivity of quaternary plasticized PEO‐based polymer electrolytes

Quaternary plasticized solid polymer electrolyte (SPE) films composed of poly(ethylene oxide), LiClO₄, Li_1.3Al_0.3Ti_1.7(PO₄)₃, and either ethylene carbonate or propylene carbonate as plasticizer (over a range of 10–40 wt%) were prepared by a solution‐cast technique. X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) indicated that components such as LiClO₄ and Li_1.3Al_0.3Ti_1.7(PO₄)₃ and the plasticizers exerted important effects on the plasticized quaternary SPE systems. XRD analysis revealed the influence from each component on the crystalline phase. DSC results demonstrated the greater flexibility of the polymer chains, which favored ionic conduction. SEM examination revealed the smooth and homogeneous surface morphology of the plasticized polymer electrolyte films. EIS suggested that the temperature dependence of the films' ionic conductivity obeyed the Vogel–Tamman–Fulcher (VTF) relation, and that the segmental movement of the polymer chains was closely related to ionic conduction with increasing temperature. The pre‐exponential factor and pseudo activation energy both increased with increasing plasticizer content and were maximized at 40 wt% plasticizer content. The charge transport in all polymer electrolyte films was predominantly reliant on lithium ions. All transference numbers were less than 0.5. Copyright © 2006 Society of Chemical Industry     

One-pot syntheses of water-soluble poly(oxamide)s

Two kinds of water-soluble polymers were synthesized by using the poly(oxamide) polyanion generated in situ from the reductive coupling polymerization of diisocyanates induced by SmI₂. One is a nonionic polymer bearing oligo(ethylene oxide) pendants, which was obtained by treating the polyanion with α-methyl-ω-(4-bromomethyl)phenylmethyl oligo(ethylene oxide). The other is an ion-containing polymer having sulfonate moieties in the side chains, which was prepared by the reaction of the polyanion with 1,3-propane sultone or sodium 4-(bromomethyl)-benzenesulfonate. In both cases, the corresponding polymers were provided in good yields, and their solubilities were found to be dependent on the structure as well as the substitution degree. The poly(oxamide) with oligo(ethylene oxide) exhibited good solubilities in common organic solvents and was soluble in aqueous system at high level of substitution. On the other hand, the poly(oxamide) with propane-sulfonic acid showed high solubility in both acidic and basic water but was insoluble in organic solvents, while the poly(oxamide) having benzylsulfonate was soluble only in DMF and DMSO. Received: 18 October 1996/Revised: 8 November 1996/Accepted: 15 November 1996     

Preparation and characterization of poly(ethylene-graft-ethylene oxide)

Graft copolymers containing poly(ethylene oxide) side chains attached to a polyethylene backbone were prepared by coupling of poly(ethylene-co-acrylic acid) (PEAA) and poly(ethylene oxide) monomethyl ethers (MPEO) by esterification in o-xylene at 140°C. The MPEO side chains had molecular weights of 750 to 5000. The chemical composition of the graft copolymers was analyzed by NMR and FT–IR spectroscopy. The weight fraction of the MPEO grafts in the graft copolymers was found to be around 0.4. The graft copolymers exhibited a phase-separated morphology with the backbones and the MPEO phase had a melting temperature 8–25°C lower than the corresponding MPEO homopolymers, as determined by DSC. The melting point of the crystalline phase formed by the PEAA main chains was close to that of the pure PEAA. Crystallinity was also confirmed by x-ray diffraction. © 1996 John Wiley & Sons, Inc.     

Aqueous reactive polyurethane prepolymer with poly(ethylene oxide) monomethyl ether side chains for the hydrophilic finishing of poly(ethylene terephthalate) fabrics

In this study, a series of aqueous polyurethane (PU) prepolymers were synthesized with 4,4‐methylene bis(isocyanatocyclohexane), poly(ethylene glycol) or polycaprolactone diol (PCL), methyl ethyl ketoxime, and dispersing centers produced by isophorone diisocyanate, N‐diethanol amine, and poly(ethylene oxide) monomethyl ether (PEO), containing different hydrophobic groups (? CH₃ and ? C₆H₄C₉H₁₉) at the end. The thermal properties of the prepolymers and the characteristics of poly(ethylene terephthalate) (PET)‐treated fabrics were investigated. The glass‐transition temperature was the highest in the CC prepolymer containing a benzene ring (? C₆H₄C₉H₁₉) and a long PEO side chain, and it was the lowest in the CA prepolymer having a longer PEO side chain. The CB prepolymer containing a shorter PEO side chain did not produce a melting point of PEO, although a heat endothermic peak of the PCL crystal appeared. The melting point and enthalpy from PEO of the CA prepolymer were larger than those of the CC prepolymer. With respect to the hydrophilic finishing effects of aqueous PU prepolymers for PET fabrics, the fabric treated with the CB prepolymer had higher add‐on and washing durability than the fabrics treated with the CA prepolymer, which was followed by the CC prepolymer with the lowest, but the opposite trend was found for the hydrophilic properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Synthesis of CdS nanoparticles dispersed within amphiphilic poly(urethane acrylate‐co‐styrene) films

CdS nanoparticles were prepared using amphiphilic urethane acrylate nonionomer (UAN) precursor chains having a poly(propylene oxide)‐based hydrophobic segment and a hydrophilic poly(ethylene oxide) segment. Cadmium salts were first dissolved in UAN/styrene solutions, and then the solutions were copolymerized to obtain poly(urethane acrylate‐co‐styrene) films containing dissolved cadmium salts. After reduction with H₂S gas, freestanding films containing CdS nanoparticles were obtained. Transmission electron microscopy images of the films showed that 9.67‐nm CdS nanoparticles were dispersed within the poly(urethane acrylate‐co‐styrene) matrix. The formation of CdS nanoparticles was also confirmed with UV absorption spectra and photoluminescence emission spectra of the films. Transmission electron microscopy and dynamic mechanical analysis measurements confirmed that hydrophilic/hydrophobic microphase separation in UAN/styrene solutions occurred during the dissociation of the cadmium salts, and the microphase‐separated structures were locked in by crosslinking copolymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2357–2363, 2005     

Relation between structure and gas transport properties of polyethylene oxide networks based on crosslinked bisphenol A ethoxylate diacrylate

Poly(ethylene oxide) (PEO) networks prepared from the photopolymerization of bisphenol A ethoxylate diacrylate (BPA-EDA) have been investigated as a function of crosslinker molecular weight and copolymer composition. Dynamic mechanical and dielectric methods have been used to elucidate the thermal relaxation characteristics of the polymers as a function of network composition and architecture, and these properties were related to measured gas transport for CO₂ separations. Copolymerization strategies involving the insertion of flexible PEG side chains along the network backbone proved effective in enhancing network free volume and increasing permeability. The gas transport performance of rubbery amorphous membranes based on the n=15 BPA-EDA crosslinker (i.e., crosslinker encompassing 30 ethylene oxide repeat units between crosslinks) compared favorably to model polymers synthesized from poly(ethylene glycol) diacrylate.     

Evaluation of the permeability and blood‐compatibility properties of membranes formed by physical interpenetration of chitosan with PEO/PPO/PEO triblock copolymers

In order to develop blood compatible membranes with controlled porosity, we have fabricated and examined the properties of physical interpenetrating network (PIN) of chitosan and poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymers (Pluronics^®). Degree of equilibrium swelling, scanning electron microscopy, and electron spectroscopy for chemical analysis (ESCA) were used to characterize the bulk and surface properties. Vitamin B₁₂ and human serum albumin were used as permeability markers. Platelet adhesion and activation were used to determine the blood‐interaction properties of the PIN membranes. Unlike chitosan membranes that were nonporous, the chitosan‐Pluronic PIN membranes were highly porous with the pore size, depending on the type of incorporated Pluronic polyol. ESCA results showed a significant increase in the ? C ? O? signal of C1s spectra on the PIN membranes that correlates with the presence of PEO chains on the surface. The permeability coefficients of vitamin B₁₂ and albumin were higher in the chitosan‐Pluronic PIN membranes than in the control. The number of adherent platelets and the extent of activation were significantly reduced on the chitosan‐Pluronic PIN membranes. The decrease in platelet adhesion and activation correlated positively with the PEO chain length of the incorporated Pluronic polyols. The results of this study show that chitosan‐Pluronic PIN membranes offer a blood‐compatible alternative with a higher‐molecular‐weight cutoff for use in hemodialysis and related applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1274–1284, 2001     

Effect of nanofiller concentration on conductivity and dielectric properties of poly(ethylene oxide)–poly(methyl methacrylate) polymer electrolytes

This paper reports the effect of nanofiller concentration on the conductivity and dielectric properties of the poly(ethylene oxide)–poly(methyl methacrylate)–poly(ethylene glycol)–AgNO₃–Al₂O₃ polymer electrolyte system. The preparation of polymer films was done using the solution‐casting technique and characterization of the films was carried out using scanning electron microscopy, differential scanning calorimetry and ionic transport techniques. The ionic conductivity, investigated using impedance spectroscopy, was expected to show interesting behaviour at below and above the melting temperature of poly(ethylene oxide) in the polymer blend films. Complex impedance data were analysed in an alternating current conductivity and dielectric permittivity formalism in order to throw light on the transport mechanism. The effect of nanofiller concentration on conduction and relaxation processes at various temperatures was studied. © 2013 Society of Chemical Industry     

In situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through an electrospinning process

Iron oxide nanoparticle coated poly(ethylene oxide) nanofibers as organic–inorganic hybrids with 200–400‐nm diameters were prepared by the in situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through the electrospinning of a poly(ethylene oxide) solution having Fe²⁺ and Fe³⁺ ions in a gaseous ammonia atmosphere. Transmission electron microscopy analysis proved the presence of iron oxide nanoparticles on the polymer nanofibers. The thermal properties of the nanofiber mat were also studied with differential scanning calorimetry and thermogravimetric analysis techniques. X‐ray diffraction showed that the formed iron oxide nanoparticles were maghemite nanoparticles. The results were compared with those of the electrospinning of a poly(ethylene oxide) solution having Fe²⁺ and Fe³⁺ ions and a pure poly(ethylene oxide) solution in an air atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Synthesis and characterization of comb‐like polymer PVC–poly(ethylene oxide)

A new series of amphiphilic graft‐copolymers, composed of poly(vinyl chloride) (PVC) backbones and poly(ethylene oxide) side chains, was synthesized by chemical modification of PVC. The synthesis was based on the reaction between chlorine in PVC (polymerization degree 700) and sodium salt of polyethylene glycol (PEG). PEGs with molecular weights of 200 and 600 were used. The graft polymers were characterized by IR and gel permeation chromatography and the molecular parameters such as the average numbers of grafting chains on the PVC backbones were calculated as well as the grafting percent. The molecular weights of PEG were found to influence the rate of the grafting reaction and the final degree of conversion. The maximum grafting percentage of the resulted polymers after the purification was ca. 34%, regardless of the molecular weight of PEG. No gel was observed in the PVC‐g‐PEOs, in spite of the average numbers of grafting chains up to 32. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 475–479, 2000     

Synthesis and characterization of linear asymmetrical poly(propylene oxide) diol

Linear asymmetrical poly(propylene oxide) was synthesized through four‐step reactions: selective benzylation, alcohol exchange reaction, propylene oxide anionic polymerization, debenzylation. One terminal of the asymmetrical polymer chains is alcohol hydroxyl and the other is phenol hydroxyl. It was characterized with infrared (IR) and ¹H Nuclear Magnetic Resonance (¹H‐NMR). Peaks at 1.11, 3.38, and 3.53 ppm were attributed to side groups (? OCH₂CH(CH₃)? ), backbone units (? OCH₂CH(CH₃)? ) and (? OCH₂CH(CH₃)? ) of poly(propylene oxide), respectively. Molecular weight and molecular weight distribution were measured with ¹H‐NMR and laser light scattering (LLS), which showed that the linear asymmetrical poly(propylene oxide) was mono‐disperse (PDI = 1.02–1.07). Then, its carbamate reaction with phenyl isocyanate was studied; the reaction rate constants for phenol hydroxyl and alcohol hydroxyl of poly(propylene oxide) were k₁ = 0.209 mol L^?1 min^?1 and k₂ = 0.051 mol L^?1 min^?1. There was a great reactivity difference for two types of hydroxyls in asymmetrical poly(propylene oxide), contrasting to the single carbamate reaction rate constant of symmetrical poly(propylene oxide) (k₃ = 0.049 mol L^?1 min^?1). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and photophysical properties of novel poly(p‐phenylene vinylene) derivatives with conjugated thiophene as side chains

Two novel poly(p‐phenylene vinylene) (PPV) derivatives with conjugated thiophene side chains, P1 and P2, were synthesized by Wittig‐Horner reaction. The resulting polymers were characterized by ¹H‐NMR, FTIR, GPC, DSC, TGA, UV–Vis absorption spectroscopy and cyclic voltammetry (CV). The polymers exhibited good thermal stability and film‐forming ability. The absorption spectra of P1 and P2 showed broader absorption band from 300 to 580 nm compared with poly[(p‐phenylene vinylene)‐alt‐(2‐methoxy‐5‐octyloxy‐p‐phenylene vinylene)] (P3) without conjugated thiophene side chains. Cyclic voltammograms displayed that the bandgap was reduced effectively by attaching conjugated thiophene side chains. This kind of polymer appears to be interesting candidates for solar‐cell applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structure dependence of photochromism of azobenzene‐functionalized polythiophene derivatives

Two novel azobenzene‐functionalized polythiophene derivatives, poly[4‐((4‐(phenyl)azo)phenoxy)butyl‐3‐thienylacetate] (PATh‐4) and the copolymer of 3‐hexylthiophene and 4‐((4‐(phenyl)azo)phenoxy)butyl‐3‐thienylacetate (COP‐64) were synthesized. The structure and photoelectronic behavior of both polythiophene derivatives were characterized by NMR, FTIR, UV–vis, XRD, GPC, modulated DSC, and photoluminescence spectroscopy. These new polymers combine photoluminescence property and photochemical behavior of both polythiophene‐conjugated backbones and the photoisomerizable moieties in the side chains. The photoluminescence property of polymers so obtained can be modified reversibly through the photochemical isomerization reaction of the photoactive groups in side chains. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Interpretation of 2H-NMR lineshapes of PEO

Summary Temperature dependent ²H-nmr lineshapes and relaxation times T_2e of poly(ethylene oxide) (PEO_d) and two block copolymers of deuterated PEO_d and protonated poly(butyl methacrylate) (PBMA_h) were measured. The results were compared with simulated lineshapes and relaxation times and discussed as the glass transition of PEO chains.     

Glass‐transition and gas‐transport characteristics of polymer nanocomposites based on crosslinked poly(ethylene oxide)

The glass‐transition and gas‐transport properties of rubbery polymer nanocomposites based on crosslinked poly(ethylene oxide) and metal oxide nanoparticles were studied. Nanocomposite samples were prepared by the UV photopolymerization of poly(ethylene glycol) diacrylate (n ～ 14) in the presence of magnesium oxide or silica nanoparticles. The thermomechanical properties of the composites were investigated with dynamic mechanical and dielectric spectroscopy methods. The inclusion of nanoparticles in the crosslinked poly(ethylene glycol) diacrylate network led to a systematic increase in rubbery modulus and a modest positive offset (～6°C) in the measured glass‐transition temperature for both systems. Bulk density measurements indicated only minimal void volume fraction in the composites, and CO₂ and light gas permeability decreased with particle loading; for example, the CO₂ infinite dilution permeability at 35°C decreased from 106 barrer in the unfilled polymer to 55 barrer in a nanocomposite containing 30 wt % magnesium oxide nanoparticles. The inclusion of toluene diluent in the prepolymerization mixtures produced a limited enhancement in sample permeability, but the sizeable increases in gas transport with particle loading reported for certain other rubbery nanocomposite systems were not realized in the crosslinked poly(ethylene glycol) diacrylate composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of thermo‐ and pH‐sensitive block copolymers bearing a biotin group at the poly(ethylene oxide) chain end

A poly(ethylene oxide)‐block‐poly(dimethylamino ethyl methacrylate) block copolymer (PEO‐b‐PDMAEMA) bearing an amino moiety at the PEO chain end was synthesized by a one‐pot sequential oxyanionic polymerization of ethylene oxide (EO) and dimethylamino ethyl methacrylate (DMAEMA), followed by a coupling reaction between its PEO amino and a biotin derivative. The polymers were charac terized with ¹H NMR spectroscopy and gel permeation chromatography. Activated biotin, biotin‐NHS (N‐hydroxysuccinimide), was used to synthesize biotin‐PEO‐PDMAEMA. In aqueous media, the solubility of the copolymer was temperature‐ and pH‐sensitive. The particle size of the micelle formed from functionalized block copolymers was determined by dynamic light scattering. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3552–3558, 2006     

Hydrogels based on poly(ethylene oxide) and poly(tetramethylene oxide) or poly(dimethyl siloxane). II. Physical properties and bacterial adhesion

To investigate the effects of polymer chemistry and topology on physical properties and bacterial adhesion, various hydrogels composed of short hydrophilic [poly(ethylene oxide) (PEO)] and hydrophobic blocks were synthesized by polycondensation reactions. Differential scanning calorimetry and X‐ray diffraction analysis confirmed that all of the hydrogels were strongly phase‐separated due to incompatibility between PEO and hydrophobic blocks such as poly(tetramethylene oxide) (PTMO) and poly(dimethyl siloxane) (PDMS). The crystallization of PEO in the hydrogels was enhanced by the incorporation of longer PEO chains, the adoption of PDMS as a hydrophobic block, and the grafting of monomethoxy poly(ethylene oxide) (MPEO). Compared to Pellethane, the control polymer, the hydrogels exhibited higher Young's moduli and elongations at break, which was attributed to the crystalline domains of PEO and the flexible characteristics of the hydrophobic blocks. The mechanical properties of the hydrogels, however, significantly deteriorated when they were hydrated in distilled water; this was primarily ascribed to the disappearance of PEO crystallity. The water capacity of hydrogels at 37°C in phosphate‐buffered saline (PBS) (pH = 7.4) was dominantly dependant on PEO content, which also influenced the thermonegative swelling behavior. From the bacterial adhesion tests, it was evident that both S. epidermidis and E. coli adhered to Pellethane much greater than to the hydrogels, regardless of the preadsorption of albumin. Better resistance to bacterial adhesion was observed in hydrogels with longer PEO chains, with PTMO as a hydrophobic block, and with MPEO grafts. The least bacterial adhesion for both species was achieved on MPEO_2k–PTMO, a hydrogel with MPEO grafts. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1505–1514, 2003     

Thermal degradation of water soluble polymers and their binary blends

The effect of five different metal oxides on the pyrolysis of poly(ethylene oxide) (PEO), polyacrylamide (PAM), and poly(vinyl alcohol) (PVA) was investigated using thermogravimetry. The presence of metal oxide did not influence the degradation of PEO while the order of metal oxide on the degradation rate of PAM and PVA was PbO > Co₃O₄ > CuO > ZnO > Al₂O₃. The miscibility and the decomposition of PEO–PAM and PVA–PAM blends were also investigated. The blends were found to be immiscible and the presence of one polymer did not influence the degradation of the other polymer in the polymer blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 233–240, 2006     

Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using ¹H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (K_v) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006