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Highlights Solid polymer electrolytes (SPEs) have gained remarkable development within the realm of new energy resources. With its improved electrochemical stability and environmental‐friendly sustainability, bacterial cellulose (BC) has emerged as a promising candidate for applications in SPEs. Herein, bacterial cellulose was chemically cyanoethylated and integrated with lithium bis(trifluoromethanesulphonyl)imide/polyethylene oxide (PEO) based SPE. Some vertical channels are formed when trace amounts (0.5 wt%) of cyanoethylated bacterial cellulose (BC‐CN) are added to PEO‐based SPE, as revealed by SEM. This formula's corresponding PEO‐based SPE presents the highest ion conductivity of 5.7 × 10−4 S cm−1 at 60°C. The ion migration activation (Ea) deduced from the Arrhenius equation is 0.48 eV, lower than the value of 0.82 eV for the pristine PEO SPE. Besides, the Li+ migration number of this modified PEO‐based solid electrolyte is calculated to be a relatively high value of 0.33, while that of its counterpart, the pristine PEO SPE, is as low as 0.06. The all‐solid‐state lithium battery with PEO/0.5%BC‐CN SPE can operate stably for 115 cycles, which is longer than the 80 cycles achieved with the pristine PEO SPE. This study introduces a novel strategy for creating modified BC composites PEO‐based SPE. Bacterial cellulose was chemically cyanoethylated. Cyanoethylated bacterial cellulose composite polyethylene oxide (PEO)‐based solid polymer electrolytes (SPEs) are prepared in DMF. Opening pores penetrate the surface of the PEO/0.5% cyanoethylated bacterial cellulose (BC‐CN) SPE membrane. PEO/0.5% BC‐CN shows ionic conductivity of 5.7 × 10−4 S cm−1 at 60°C. Full cell with PEO/0.5% BC‐CN performs stably for 115 cycles. [ABSTRACT FROM AUTHOR]

High flame retardancy, satisfactory mechanical properties are crucial for polymeric composites employed in fields with safety requirements. Inorganic fillers can effectively regulate the structure and composition of polymeric materials and have become an effective strategy for fabricating high-performance polymeric composites. Herein, aluminum phosphate–coated sepiolite (Sep@AlPO4) fillers are fabricated as a multifunctional additive to modify polyethylene oxide (PEO), PEO nanocomposites were prepared via incorporation of Sep@AlPO4 and phenethyl-bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (DiDOPO) in the PEO matrix, and the synergistic effects between Sep and AlPO4 are discussed. The results reveal that Sep@AlPO4 could simultaneously enhance the flame retardancy and strengthen the mechanical properties of PEO/DiDOPO. Additionally, Sep@AlPO4 could increase the viscosity, storage modulus, and loss modulus of the composites. This study provides an effective strategy for fabricating enhanced flame retardants to improve the performance of polymers. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide) (PEO) adsorption behavior on kaolinite surfaces in an aqueous solution was investigated through experiments, the density functional theory (DFT), and molecular dynamics (MD) simulations. The experimental results showed that as the PEO concentration increased, the adsorption capacity first increased then slightly decreased and the turbidity change was opposite. The adsorption isotherm on the kaolinite surface was more suitable for the Langmuir model and valid for single-layer adsorption. The results of simulations showed that the PEO chains extended along the two basal surfaces of kaolinite or were partly adsorbed, forming loops and tails that caused most of the particles to flocculate, contributing to the turbidity lowering. When the number of PEO chains was excessive, their self- and inter-aggregation occurred with some PEO far from the surface, and the turbidity increased. On the kaolinite (001) surface, the hydrogen bonds between the PEO ether O and the hydroxyl groups constituted the main interaction mechanism. However, the hydrophobic force of the (CH2-CH2)-moiety of PEO might have dominated its adsorption on the (001) surface. The hydrogen bonds were stronger than the hydrophobic interactions. [ABSTRACT FROM AUTHOR]

A 3D fiber-network-reinforced PEO-based composite polymer electrolyte for high-temperature lithium metal batteries is prepared with a polyimide framework and trimethyl phosphate plasticizer. It works stably in a wide working temperature range from 40 to 140 °C. Remarkably, the LiFePO 4 /Li cell with the composite electrolyte performs stably for over 300 cycles at 120 °C and it can still survive 80 cycles at 140 °C. [Display omitted] Traditional liquid lithium-ion batteries are not applicable for extreme temperatures, due to the shrinkage of separators and volatility of electrolytes. It is necessary to develop advanced electrolytes with desirable characteristics in terms of thermal stability, electrochemical stability and mechanical properties. Solid-state electrolytes, such as polyethylene oxide (PEO), outperform other types and bring the opportunity to realize the high-temperature lithium-ion batteries. However, the softness of PEO at elevated temperatures leads to battery failure. In this work, a three-dimensional fiber-network-reinforced PEO-based composite polymer electrolyte is prepared. The introduced polyimide (PI) framework and trimethyl phosphate (TMP) plasticizer decrease the crystallinity of PEO and increase the ionic conductivity at 30 °C from 8.79 × 10−6 S cm−1 to 4.70 × 10−5 S cm−1. In addition, the PEO bonds tightly with PI fiber network, improving both the mechanical strength and thermal stability of the prepared electrolyte. With the above strategies, the working temperature range of the PEO-based electrolytes is greatly expanded. The LiFePO 4 /Li cell assembled with the PI-PEO-TMP electrolyte stably performs over 300 cycles at 120 °C. Even at 140 °C, the cell still survives 80 cycles. These excellent performances demonstrate the potential application of the PI-PEO-TMP electrolyte in developing safe and high-temperature lithium batteries. [ABSTRACT FROM AUTHOR]

We developed a composite membrane based on polyethylene oxide (PEO), achieving high CO 2 selectivity, by incorporating 7,7,8,8-tetracyanoquinodimethane (TCNQ)-modified CuO nanoparticles into the PEO matrix. The addition of TCNQ helps in evenly distributing the CuO nanoparticles throughout the membrane, preventing them from clumping together. This treatment not only enhances the dispersion of CuO particles but also imparts a positive charge to their surface, which is beneficial for increasing the selectivity for CO 2 over N 2. The extent of this surface charge modification on the CuO nanoparticles was evaluated using X-ray photoelectron spectroscopy (XPS), while the synergy between the polymer and the additives was verified through Fourier-transform infrared (FT-IR) spectroscopy studies. The combination of CuO nanoparticles in the membrane contributes to both barrier and carrier effects, enhancing the gas selectivity. This is further aided by the intrinsic properties of PEO, a rubber-like polymer known for its good gas permeance. As a result of these combined effects, the PEO/CuO/TCNQ membrane exhibited a remarkable CO 2 selectivity of 393 and a CO 2 permeance of 3.9 gas permeation unit (GPU). The superior separation performance of this membrane can be ascribed to three main factors: enhanced solubility due to the oxide layer on the particle surfaces and in the polymer matrix, improved transport efficiency via reversible interactions thanks to the positively charged surface, and the effective barrier provided by the nanoparticles against N 2 transport. These findings are expected to contribute significantly to future studies on the surface modification of metal nanoparticles and in the field of gas separation membranes. [Display omitted] • Modified surface energy of CuO by 7,7,8,8-tetracyano quinodimethane. • Accelerated gas transport on the surface of CuO. • Highly selective performance based on polymer composite. [ABSTRACT FROM AUTHOR]

Plasma-assisted vapor-phase deposition of (–CH 2 –) 100 macromolecules is performed onto the surface of pre-deposited polyethylene oxide (PEO). It leads to the formation of two-dimensional 7 nm thick polyethylene (PE) islands of the ramified fractal or ordered dendrite shape. AFM-infrared nanospectroscopy confirms the phase separation whereas complementary specific heat nanocalorimetry indicates that the crossover from one island shape to another is related to glassy dynamics in underlying PEO. Segmental dynamics is found to be controlled by the thickness of PEO and it manifests in the development of star-shaped PE dendrites on ultrathin (<30 nm, strongly-confined) PEO. For thicker (~100 nm, weakly-confined) PEO, the PE islands grow close to a diffusion-limited aggregation regime. Otherwise, segmental mobility in PEO can be controlled by cross-linking which is enhanced under higher discharge power. The results provide a new physical insight into solvent-free macromolecular diffusion at vacuum/polymer interface and may stimulate the vacuum-compatible development of new polymer-based devices. Unlabelled Image • Plasma-assisted vapor-phase deposition of (–CH 2 –) species on polyethylene oxide is done. • Polyethylene forms 2D nano-islands on polyethylene oxide surface. • AFM-IR nanospectroscopy is used to study phase separation. • Fractal or dendrite island shape depends on glassy dynamics of polyethylene oxide. [ABSTRACT FROM AUTHOR]

Abstract Observations of large property changes in the presence of nanoparticles have motivated an increasing interest towards the interfacial effect in polymer nanocomposites. In this work, the interface between poly(ethylene oxide) (PEO) and silica (SiO 2) was modulated by the inclusion of SiO 2 with three different surface functionalities, namely unfunctionalized SiO 2 (SiO 2 -OH, grafting density = 0 chains/nm2), PEO-grafted SiO 2 , SiO 2 - g -PEO-1.1 (grafting density = 1.1 chains/nm2) and SiO 2 - g -PEO-2.2 (grafting density = 2.2 chains/nm2), and the interfacial effect on crystallization behavior of PEO/SiO 2 nanocomposites was studied by the combination of differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM) analysis. In contrast to the unfunctionalized SiO 2 , PEO grafting imparts SiO 2 with a high nucleation ability, even though SiO 2 -OH demonstrates more homogenous dispersion in PEO matrix than PEO-grafted SiO 2. The overall crystallization rate of PEO/SiO 2 nanocomposites follows the order PEO/SiO 2 - g -PEO-2.2 > PEO/SiO 2 - g -PEO-1.1 > PEO/SiO 2 -OH. These results highlight the role of grafted chains on crystallization. It is speculated that the interfacial structure, as a function of grafting density, plays a critical role in the formation of nuclei, which ultimately determines the crystallization behavior. This work can contribute to understanding the interfacial effect in polymer nanocomposites and is believed to provide theoretical guidance for manipulating the properties of materials. Graphical abstract Image 1 Highlights • A marked enhancement in the crystallization rate of PEO with the inclusion of the PEO-grafted SiO 2 nanoparticles. • Increased nucleation power of PEO-grafted SiO 2 nanoparticles with the grafting density. • Well-illustrated interfacial structures as a function of grafting density. • Highlighting the role of grafted chains on crystallization. • Correlating the interfacial structures with the crystallization of polymer nanocomposites. [ABSTRACT FROM AUTHOR]

The properties of polymeric materials are dictated not only by their composition but also by their molecular architecture. Here, by employing brush‐first ring‐opening metathesis polymerization (ROMP), norbornene‐terminated poly(ethylene oxide) (PEO) macromonomers (MM‐n, linear architecture), bottlebrush polymers (Brush‐n, comb architecture), and brush‐arm star polymers (BASP‐n, star architecture), where n indicates the average degree of polymerization (DP) of PEO, are synthesized. The impact of architecture on the thermal properties and Li+ conductivities for this series of PEO architectures is investigated. Notably, in polymers bearing PEO with the highest degree of polymerization, irrespective of differences in architecture and molecular weight (~100‐fold differences), electrolytes with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as an Li+ source exhibit normalized ionic conductivities (σn) within only 4.9 times difference (σn = 29.8 × 10−5 S cm−1 for MM‐45 and σn = 6.07 × 10−5 S cm−1 for BASP‐45) at a concentration of Li+r = [Li+]/[EO] = 1/12 at 50 °C. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 448–455 Brush‐first ring‐opening metathesis polymerization (ROMP) provides norbornene‐terminated macromonomers (linear architecture), bottlebrush polymers (comb architecture), and brush‐arm star polymers (BASPs) (star architecture) with varied lengths of poly(ethylene oxide) (PEO) chains. The impact of those distinct PEO architectures on thermal properties and Li+ conductivity is investigated. Notably, these polymers with varied architectures are derived from the same components. [ABSTRACT FROM AUTHOR]

Polymer electrolytes are of tremendous importance for applications in modern lithium‐ion (Li+‐ion) batteries due to their satisfactory ion conductivity, low toxicity, reduced flammability, as well as good mechanical and thermal stability. In this study, the Li+‐ion conductivity of well‐defined poly(ethylene oxide) (PEO) networks synthesized via copper(I)‐catalyzed azide–alkyne cycloaddition is investigated by electrochemical impedance spectroscopy after addition of different lithium salts. The ion conductivity of the network electrolytes increases with increasing molar mass of the PEO chains between the junction points which is completely opposite to the behavior of their respective uncrosslinked linear precursors. Obviously, this effect is directly related to the segmental mobility of the PEO chains. Furthermore, the ion conductivity of the network electrolytes under investigation increases also with increasing size of the anion of the added lithium salt due to a weaker anti‐plasticizing effect of the more bulky anions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 21–28 The ion conductivity of electrolytes based on poly(ethylene oxide) (PEO) networks is studied with respect to the molar mass between the junction points which shows a completely opposite behavior than the linear PEO electrolytes. In addition, the network electrolytes containing lithium salts with bulky anions had a higher ion conductivity than the respective electrolytes containing a salt bearing a small anion since their crystallinity is significantly lower and their glass transition temperature is only slightly increased. [ABSTRACT FROM AUTHOR]

A novel phenolic resin (phenolic containing diphenyl oxide [named by MPF]) was synthesized and blended with poly(ethylene oxide) (PEO). In modified PEO, the shear‐thinning behavior appears and shortage modulus (G′) deviates from classic terminal behavior. Compared with PEO, there is an increase in the nucleation rate and a decrease in the growth rate of spherulites in modified PEO. A small amount of MPF plays a role of the nucleating agent of PEO. The addition of MPF into PEO makes the glass transition temperature (Tg) and thermal decomposition temperature (Td5%) of PEO higher. When the content of MPF is 2%, the Td5% of MPF/PEO is 346°C, which is much higher than that of pure PEO (240°C). When the content of MPF is 50%, Tg of PEO is up to 26°C, which is 90°C higher than that of pure PEO. [ABSTRACT FROM AUTHOR]

Abstract The understanding of the formation and movement of charges inside solid polymer electrolytes is a critical point of the research for the development of better lithium-ion batteries (LIBs). In order to facilitate the understanding of the charge distributions, the Kelvin probe force microscopy with a reliable statistical data analysis approach has been used. As poly(ethylene oxide) (PEO) is a material used as an electrolyte in LIBs, the PEO and its salt compound with lithium perchlorate (LiClO 4) were investigated with this approach. The transient formation and movement of internal potential and simultaneously the charge distribution were investigated with respect to time under biased and unbiased conditions. [ABSTRACT FROM AUTHOR]

Amorphous polymers containing poly(ethylene oxide) are leading membrane materials for CO 2 capture from fossil fuel-derived flue gas and syngas, such as those prepared from poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) methyl ether acrylate (PEGMEA). This work shows that introduction of zeolitic imidazolate framework-8 (ZIF-8) nanoparticles in these polymers increases CO 2 permeability with minimal effect on CO 2 /H 2 and CO 2 /N 2 selectivity. Specifically, ZIF-8 nanoparticles with a size of 150–250 nm were synthesized and fabricated into mixed matrix materials (MMMs). The effect of ZIF-8 loading on gas transport properties at 35 °C in MMMs was systematically investigated. Adding 10 wt% ZIF-8 in the crosslinked PEGDA increases CO 2 permeability from 130 Barrers to 320 Barrers unexpectedly by 170% without any reduction of CO 2 /light gas selectivity. While the CO 2 /light gas selectivity in the MMMs can be satisfactorily described using the Lewis-Nielsen model, the model underestimates the gas permeability. Despite a body of studies of MMMs comprising ZIFs, this work represents one of the few on the MMMs based on amorphous rubbery polymers elucidating the effect of ZIF-8 loading on the polymer properties and demonstrating their impact in achieving superior CO 2 /H 2 and CO 2 /N 2 separation properties. [ABSTRACT FROM AUTHOR]

Poly(acrylic acid)-poly(ethylene oxide) (PAA-PEO) interpolymer complexes (IPC)s were prepared with equimolar stoichiometric ratio of repeating units and converted to crosslinked nanogels via γ-ray irradiation of aqueous acetone solutions. The effect of acetone concentration on the coil size of nanogels was investigated by dynamic light scattering (DLS). pH and temperature effects on the size and surface charge of nanogels were studied by using DLS. Zeta potentials of the PAA-PEO nanogels were between − 5.31 mV (pH = 2) and − 45.00 mV (pH = 11) depending on dissociation of PAA. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) pictures showed that dry PAA-PEO nanogels are spherical with diameters of ~ 100 and ~ 240 nm in the swollen state as determined by DLS. PAA-PEO nanogels synthesized in 25% (v/v) acetone/water mixture exhibited size stability over a period of 2 months. This simple method of preparing nanogels from polymer pairs avoids tiresome synthesis of corresponding block copolymers as precursors of functional nanogels.Formation of poly(acrylic acid)-poly(ethylene oxide) (PAA-PEO) nanogels from interpolymer complexes and radiation-induced crosslinking [ABSTRACT FROM AUTHOR]

The Kendrick mass defect (KMD) analysis of multiply charged polymeric distributions has recently revealed a surprising isotopic split in their KMD plots—namely a 1/z difference between KMDs of isotopes of an oligomer at charge state z. Relying on the KMD analysis of actual and simulated distributions of poly(ethylene oxide) (PEO), the isotopic split is mathematically accounted for and found to go with an isotopic misalignment in certain cases. It is demonstrated that the divisibility (resp. indivisibility) of the nominal mass of the repeating unit (R) by z is the condition for homolog ions to line up horizontally (resp. misaligned obliquely) in a KMD plot. Computing KMDs using a fractional base unit R/z eventually corrects the misalignments for the associated charge state while using the least common multiple of all the charge states as the divisor realigns all the points at once. The isotopic split itself can be removed by using either a new charge-dependent KMD plot compatible with any fractional base unit or the remainders of KM (RKM) recently developed for low-resolution data all found to be linked in a unified theory. These original applications of the fractional base units and the RKM plots are of importance theoretically to satisfy the basics of a mass defect analysis and practically for a correct data handling of single stage and tandem mass spectra of multiply charged homo- and copolymers.ᅟ [ABSTRACT FROM AUTHOR]

A series of solid polymer electrolytes (SPEs) based on waterborne polyurethane (WPU), poly(ethylene oxide) (PEO) and lithium bis(trifluoromethane sulfonimide) (LiTFSI) are fabricated via a solvent free process. Field emission-scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry techniques are used to characterize the morphological features of the SPEs. The self-supported blend SPEs have sufficient mechanical strength and electrochemical stability compared to the pristine PEO electrolyte. The SPE2 (30 wt% LiTFSI in PEO:WPU = 3:1) electrolyte presents the superior comprehensive performance with a stress of 1.3 MPa and electrochemical window exceeding 4.8 V. All-solid-state LiFePO 4 /SPE2/Li cell using this blend solid polymer electrolyte exhibits both superior discharge capability and cycle performance (high initial discharge capacity of 160 mAh g −1 at 0.2 C, 122 mAh g −1 discharge capacity and 96% capacity retention after 100 cycles at 1 C) at 80 °C. All of these results demonstrate that this new WPU/PEO blend solid polymer electrolyte is a promising candidate for all-solid-state lithium ion batteries. [ABSTRACT FROM AUTHOR]

Authors present a phenomenological view on dielectric relaxation in polymer electrolytes, which is monitored by electrochemical impedance spectroscopy. Molecular interaction of polymer chains with salt molecules (or dipole-dipole interaction between segments and salt molecules) leads to dipolar molecular entities. Frequency-dependant impedance spectra are the key quantities of the interest for determination of electric properties of materials and their interfaces with conducting electrodes. Salt concentration serves as parameter. Bulk and interfacial properties of the samples are discussed in terms of impedance (Z*) and modulus (M*) spectra. We focus on two different classes of systems, i.e. high molar mass of poly(ethylene oxide) (PEO)+lithium perchlorate (LiClO4) (i.e. the inorganic salt) and epoxidized natural rubber (ENR-25) with 25 mol% of epoxide content+LiClO4. Impedance spectra with salt content as parameter tell us that we have interaction between dipolar entities leading to dispersion of relaxation times. However, as scaling relations show, dispersion of relaxation times does not depend on salt content in the PEO system. The relaxation peak for the imaginary part of electric modulus (M″) provides information on long-range motion of dipoles. Summarizing the results from imaginary part of impedance spectrum (Z″), tan δ (imaginary/real of permittivities) and M″ for the two systems under the discussion, PEO behaves like a mixture of chains with dipoles. There are interactions between the dipoles, but they are relaxing individually. Therefore, we see PEO-salt system as a polymer electrolyte where only a tiny fraction of added salt molecules becomes electrically active in promoting conductance. However, ENR-25-salt system behaves just as a macroscopic dipole and it can not display electrode polarization or electric relaxation because there is no mobility of individual dipoles. Hence, ENR-25-salt does not form a polymer electrolyte in the classic sense. [ABSTRACT FROM AUTHOR]

Objective:Fine particle ethylcellulose (FPEC) or poly(ethylene oxide) (PEO) addition to a Kollidon CL-SF was investigated to address low yield and poor sphericity in extruded-spheronized pellets. Significance:The success of crospovidone as a diluent in extrusion–spheronization was dependent on a small particle size of the polymer. FPEC aided production of rugged and spherical pellets using a large particle size grade, Polyplasdone®XL. PEO acted as an extrusion–spheronization aid when ethylcellulose was the diluent. These extrusion–spheronization aids could serve in this role when Kollidon®CL-SF (K CL-SF) is the diluent. Methods:The influence of formulation and process variables on pellet properties was investigated using design of experiments. A planetary mixer was used to prepare powder blends and the wetted mass after addition of water. An EXD 60 extruder produced extrudate that was spheronized in a Q230 marumerizer. Wet pellets were dried in a forced-air oven. Results:FPEC improved rounding up but reduced pellet yield. Poly(ethylene oxide) imparted desired characteristics to the wetted mass, the extrudate, and the spheronized pellets. Pellet average diameter, yield, sphericity, aspect ratio, friability, and dissolution profile were assessed. Equations for pellet characteristics facilitated discussion of the influences of factors and their interactions. Optimization was performed on pellets that included PEO. Conclusions:PEO proved to be an exceptional extrusion–spheronization aid in the preparation of pellets using K CL-SF. It facilitated wetted mass extrusion with minimal mass loss to the extruder, and markedly improved the sphericity of the pellets produced by marumerization. Immediate release pellets were obtained. [ABSTRACT FROM AUTHOR]

We discuss how the “spherulites ring” morphology and “coffee ring” profile of PEO film formed by the drying droplet at glass substrate with different heating rate. Upon increasing the heating rate of substrate, it is found that deposited PEO film from drying droplet shows the unusually observed “coffee ring” profile and “spherulites ring” morphology. The main mechanism for this phenomenon is proposed to be an enhanced Marangoni convection which is induced by the increased solute concentration gradient and reduced viscous force above 70 °C. A simple formation mechanism of the unusually observed “coffee ring” profile and “spherulites ring” morphology is proposed. These findings can be exploited to trace the center of Marangoni convection, with potential applications in designing the spherulite patterns of crystalline polymer films in ink-jet printing and self-assembly fields. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide) (PEO) is the gold standard matrix for polymer electrolytes used in actual all-solid lithium batteries. However, PEO solid polymer electrolytes show some limitations; such as relatively low ionic conductivity and lithium transference number resulting in the actual polymer-lithium batteries operating at 70 °C. In the last years, polycarbonates (PC) have been presented as an alternative polymer matrix with superior ionic conductivity for solid batteries which may work at room temperature. In this article we systematically investigated the properties of new polymers which combine varying composition of both ethylene oxide and carbonate groups. A series of poly(ethylene oxide carbonates) (PEO-PCs) have been synthesized by polycondensation between different ethylene oxide diols and dimethyl carbonate. As a result, eight new PEO-PCs with number of ethylene oxide units ranging from 2 to 45 between carbonate groups were synthesized and characterized in terms of physico-chemical properties (T m and T g ). These PEO 2-45 -PC were formulated as solid polymer electrolytes (SPE) by adding different amounts of bis(trifluoromethane)sulfonimide lithium salt. The effect of the SPE composition (ethylene oxide/carbonate ratio, salt content) on the ionic conductivity and thermal properties (glass transition temperature and melting temperature) was investigated. The optimum SPEs showing the lowest glass transition temperature led to highest ionic conductivity value of 3.7·10 −5  S cm −1 at room temperature. FTIR spectra revealed the coordination between the carbonate groups in the polymer chain and the lithium salt. 7 Li- 19 F NMR analysis T 1 relaxation and diffusion coefficients measurements indicated local dynamics that correlates with the general conductivity behaviour. [ABSTRACT FROM AUTHOR]

Abstract: The poly(ethylene oxide) (PEO) is employed as one typical example to demonstrate a new multiscale modeling scheme for simulating high‐molecular‐weight polymeric melts. In this scheme, the structural distributions and the densities at five elevated temperatures at 1 atm, which are obtained from molecular dynamics (MD) simulations of all‐atomistic oligomeric melt, are employed as the target functions to parameterize the coarse‐grained (CG) potentials. The extensive CG MD simulations reproduce the densities at a wide temperature range, from which the glass transition temperatures (Tg) and the volumetric expansion coefficients can be determined for the PEO bulks. These results confirm that the so‐developed CG potentials exhibit excellent chain‐length and temperature transferability. Furthermore, some essential structural properties and dynamics speedup features are captured, and the latter qualitatively dictates the agreement in Tg. Such a scheme can play an important role in predicting thermomechanical properties of specific complex polymers. [ABSTRACT FROM AUTHOR]

Kinetic analysis of the non-isothermal degradation of poly(ethylene oxide) has been performed using isoconversional model-free methods, model-fitting methods, invariant kinetic parameters method and Netzsch Thermokinetics software in order to establish whether different kinetic approaches yield consistent kinetic parameters. It has been shown that these approaches yield consistent kinetic parameters and can be combined in such a way as to enhance the reliability and quality of each other and consequently the overall kinetic analysis. The most probable kinetic parameters for the non-isothermal degradation of poly(ethylene oxide) have been determined. These kinetic parameters have been used for prediction of isothermal kinetics of poly(ethylene oxide), and their potential for reliable prediction has been noticed. [ABSTRACT FROM AUTHOR]

Polymer electrolytes (PEs) have attracted much attention due to their numerous applications such as rechargeable batteries, sensors, electro chromic devices, super capacitors, etc. A series of poly(ethylene oxide) (PEO) and sodium iodide (NaI) based PEs were prepared with different concentrations, hereafter referred to as the number of oxygen atoms (n) to a sodium (n:1). In this study samples with n = 7.5,10,15,20,30,40,50,60 and 80 were prepared. In this study, PEO was used as the polymer. Acetonitrile, sodium iodide was used as solvent and salt, respectively. Free standing films of polymer electrolytes were prepared using solvent casting method. Samples were characterized by different experimental techniques like complex impedance spectroscopy, DC conductivity, polarized light microscopy and Differential Scanning Calorimetry (DSC). The dependence of salt concentration on ionic conductivity of PEO-NaI PEs was investigated using complex impedance spectroscopy whereas the changes in the spherulite formation of PEs, was observed using Polarized light microscopy. DC polarization test was used to calculate ionic transference numbers. The melting temperature and melting enthalpy were studied using DSC. The ionic conductivity increased with increasing salt concentration and the sample temperature. The amorphous nature was increased with the increasing salt concentration. This is evident from the slight reduction in the onset and the maximum temperature of the pure PEO melting peaks in samples with high salt concentrations. This is supported by the images of spherulites obtained using the polarized light microscope. Fourier Transform Infrared (FTIR) spectroscopy studies show the cation polymer interactions an important concept in ionic transport mechanism. [ABSTRACT FROM AUTHOR]

Semi-interpenetrating polymer networks (s-IPNs) fabricated from linear polyimides entwined by crosslinked poly(ethylene oxide) (PEO) networks are reported in this work as CO 2 -selective separation membranes. While keeping the overall PEO content constant (~ 70 wt%), the structural characteristics of s-IPNs, i.e., the distribution and the connectivity of PEO domains, were systematically varied by adjusting the PEO content in the linear polyimide component and the crosslink density of the PEO networks, leading to six unique s-IPNs. Tested s-IPNs showed significantly improved mechanical strength and ductility relative to crosslinked pure PEO membranes, with the tensile strength of s-IPNs being nearly 4-times and > 7-times as high as those of the crosslinked pure PEO membranes with high and low crosslink density, respectively. Moreover, all s-IPNs featured greatly improved CO 2 permeability (up to 25 fold) and CO 2 /H 2 and CO 2 /N 2 selectivity compared to their linear (co)polyimide counterparts. Several s-IPNs outperform the 2008 Robeson upper bound for CO 2 /H 2 and closely approach the CO 2 /N 2 upper bound. In general, incorporating PEO segments in the linear polyimides and utilizing low-crosslink-density PEO networks are beneficial in improving both CO 2 permeability and ideal selectivity. Overall these PEO-rich s-IPNs provide an attractive membrane platform for high performance CO 2 separation applications. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte (SPE) membranes composed of thermoplastic polyurethane (TPU), poly(ethylene oxide) (PEO) and lithium bis(trifluoromethane sulfonimide) (LiTFSI) are prepared and investigated in this work. The results show that addition of TPU to the blend polymer results in loss of the crystallinity of PEO and improve the dissolution of lithium salts into the SPE matrix. TPU can also improve the mechanical stability and the electrochemical properties. Among the TPU/PEO blend electrolytes, the TPU/PEO = 1:3 based electrolyte presents an ionic conductivity of 5.3 × 10 −4 S cm −1 with electrochemical stability above 5 V (vs. Li + /Li) at 60 °C. The LiFePO 4 /SPE/Li coin cell based on SPE (TPU/PEO = 1:3) is assembled and shows the attractive discharge capacity (140 and 154 mAh g −1 at 0.2C under 60 and 80 °C, 112 and 127 mAh g −1 at 1C under 60 and 80 °C) and outstanding cycling stability (close to 96% and 94% after 100th cycles at 1C under 60 and 80 °C), respectively. These results demonstrated that the TPU/PEO blend polymer electrolyte should be a promising electrolyte for all-solid-state lithium ion batteries. [ABSTRACT FROM AUTHOR]

Lack of precise thermal control in poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) with molar masses well above M > 104 g mol−1 during preparatory stage often demonstrates molar mass dependence on thermal properties and ionic conductivities. In the earlier study, PEO-based SPEs were heated under inert atmosphere above the melting temperature of PEO and then cooled down for subsequent isothermal crystallization. The system demonstrates insignificant variation with respect to molar mass of PEO at constant salt concentration for thermal properties, ionic conductivity and intermolecular interaction. Here, we report the subsequent results of rheology and microscopic heterogeneity as a function of PEO molar mass ( Mɳ = 3 × 105 and 4 × 106 g mol−1) and lithium salt concentration (0-13 wt.%). Above the solubility limit of PEO, the glass transition studied using differential scanning calorimetry shows the presence of microscopic heterogeneity of the systems as indicated by the change in enthalpy of endothermic overshoot near the endset of glass transition. Rheological parameters were measured over a wide range of frequency (0.01 to 100 Hz) at different temperatures (30, 60 and 80 °C) using parallel plate geometry. Melt rheology system reveals that neat PEO at 80 °C exhibits restriction in the long-range motion of the chains. When incorporated with salt, it exhibits further deviation from the terminal viscoelastic relaxation behaviour. This study agrees with our previous findings that influence of molar mass of PEO in this range is insignificant on the melt rheology and microscopic heterogeneity at constant salt concentration. [ABSTRACT FROM AUTHOR]

Polyethylene oxide (PEO)-containing multi-block copolymers are good candidates for CO 2 membrane separations because of their strong affinity for CO 2 but PEO crystallization and weak mechanical properties are two limitations to be overcome at high PEO content. In this work, PEO block incorporation within new linear multi-block copolymers avoided PEO crystallization. The copolymers consisted in Jeffamine soft blocks (SB) and particularly stiff urea-imide hard blocks for improved physical cross-linking and excellent film-forming ability. Varying the SB content from 41 to 70 wt% led to different copolymer physical properties, morphology and CO 2 permeation properties. The copolymer with the lowest SB content was a rigid glassy material with very weak phase separation. Its soft and hard blocks formed large interpenetrated domains, resulting in low CO 2 permeability (2 Barrer) but extreme selectivity (α CO2/N2 = 207) for CO 2 /N 2 separation at 2 bar and 35 °C. CO 2 permeability greatly improved with the SB content due to strong phase separation. The copolymer with the highest SB content was a thermoplastic elastomer with soft blocks forming well-separated highly permeable percolating nano-domains. Its CO 2 permeability (57 Barrer) and high selectivity (α CO2/N2 = 50) are among the best properties reported for PEO-containing multi-block copolymers for CO 2 capture. [ABSTRACT FROM AUTHOR]

Terahertz time-domain spectroscopy (THz-TDS) was employed to characterize the structure and α→β phase transformation of poly(ethylene oxide) (PEO)-urea complexes. While the THz responses of α- and β-form complexes are both originated from hydrogen bonding interactions, they possess different THz absorption bands. The α-form PEO-urea complex shows two bands at 1.12 and 1.24 THz, which are vibration modes due to the hydrogen bonding among urea and between PEO and urea, respectively; the β-form PEO-urea complex shows a band at 1.48 THz, which is a vibration mode due to the hydrogen bonding among urea. A polarized THz-TDS study demonstrates that the urea-urea hydrogen bonding direction rotates 90° during the β→α transformation process. This study reveals the great potential of THz-TDS for investigating polymer-small molecule complexes. [ABSTRACT FROM AUTHOR]

Polymeric membranes containing polyethylene oxide (PEO) groups are promising CO 2 separation materials, but suffer from the trade-off between separation performance and mechanical strength. To overcome this challenge, we combine the merits of semi-interpenetrating polymer network and nanohybrid to maintain a high PEO loading and robust membrane structure. The membranes were prepared by introducing in-situ formed PEO networks with silica nodes into Pebax1657 to produce a semi-interpenetrating network structure. The introduced network and in situ formed silica nanoparticles reduce the chain packing efficiency of Pebax matrix to enhance the CO 2 diffusivity, while the increased PEO content enhances CO 2 solubility. Under feed gas pressure of 25 bar, nanohybrid membranes containing 40 wt% polymer network display excellent gas separation performance with CO 2 permeability of 272.8 Barrer and CO 2 /N 2 selectivity of 79.6 under mixed gas separation tests, surpassing 2008 Robeson upper bound. Moreover, the hybrid membranes showed high mechanical strength, the Young's modulus increases by 1.95 times. This strategy provides a simple route for the design of nanohybrid membranes with high separation performance as well as excellent durability. [Display omitted] • SIPN structure with nanoparticles as nodes was fabricated. • The in-situ formed nano-SiO 2 are uniformly distributed within hybrid membranes. • SIPN structure significantly enhances the mechanical strength of membrane. • The separation performances surpass the upper bound of CO 2 /N 2. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide) (PEO) based electrolytes are of great importance for applications in electrochemical devices. Since their ion conductivity is severely hampered by crystallization, several approaches are carried out to enhance the low temperature ion conductivity of PEO such as the addition of polar solvents or the synthesis of more complex polymer architectures. In this study, solvent-like defects are introduced in the center of the PEO chain to reduce its crystallinity with the aim to enhance ion conductivity. The ion conductivities of four polymer electrolytes, containing either a 1,4-disubstituted 1,2,3-triazole (TR) or ortho- , meta- or para- disubstituted benzene defects are measured by impedance spectroscopy after addition of lithium perchlorate (LiClO 4 , EO:Li = 50:1) to the polymer. The TR containing sample shows a 15 to 700 times higher ion conductivity at T = − 10 °C as compared to the benzene containing PEOs with different substitution pattern. This can be explained by the lower glass transition temperature of the TR containing electrolytes compared to the benzene containing electrolytes. Furthermore, the dependence of the ion conductivity on the LiClO 4 concentration in the melt at T = 70 °C is studied for TR containing electrolytes and compared to the respective defect free PEO 22 electrolytes. The electrolytes with the TR defect have higher conductivities in the concentration range (50:1 ≥ EO:Li ≥ 8:1) compared to the uninterrupted PEO 22 revealing that the incorporation of a solvent-like defect with high dielectric constant into a PEO chain is an effective strategy to enhance the ion conductivity of PEO electrolytes. This is also supported by 7 Li NMR spectroscopy showing that LiClO 4 is soluble 1,2,3-triazole but insoluble in benzene. Additionally, 1,2,3-triazoles can also coordinate Li + -ions and, thus, actively contribute to the transport of the Li + -ions. [ABSTRACT FROM AUTHOR]

10 MHz QCM quartz crystals, uncoated or coated with films of PMMA and/or PEO, were rapidly submerged into aqueous medium. The changes in these crystals' resonance frequencies were recorded. In all cases after a few seconds crystal's resonant frequency became constant at a value that depended upon whether the crystal was polished or etched and whether it was coated or uncoated with a polymer film. A blended polymer film composed of PMMA and PEO, when coated on a QCM crystal and then submerged in water showed a rapid frequency increase corresponding to the removal (leaching) of PEO from the film and creating a porous PMMA film whose pores were filled with water. The porosity of the leached film was determined. [ABSTRACT FROM AUTHOR]

Strongly interacting amorphous poly(p-vinyl phenol) (PVPh) was added into semi-crystalline poly(ethylene oxide) (PEO) at 20 wt.% to generate dendritic lamellae of alternating birefringence colors, which intertwine roughly in the radial directions as periodic stripes. Optical and atomic-force microscopy analyses are performed on revealing lamellae assembly in highly dendritic PEO spherulites by crystallizing PEO/PVPh (80/20) at crystallization temperature ( T ) equals to 45 °C. The lamellae of two opposite colors in the same PEO spherulite quadrant are exactly of same geometry (of elongated plates, each being 0.2 μm in width and 2-5 μm in length), but they fan out +/−45, respectively, as they grow away from the radial direction. The opposite colored-lamellae are radiating out in radial directions, interweaving each other to display alternating colors in radial alignment. However, such alternating colors can also be similarly seen in ring-banded spherulites in many polymers. The results presented in this study have demonstrated that the lamellae of alternating birefringent colors cannot only be seen in banded spherulites, but also in spherulites with radial dendrites. [ABSTRACT FROM AUTHOR]

ABSTRACT Soy protein isolate (SPI) is used to modify energy storage performances of poly(ethylene oxide) (PEO). The pure PEO membranes are highly polar, but the extremely high energy loss led to very low discharged energy density for use. The addition of SPI in both high molecular weight PEO and low molecular weight PEO lead to greatly reduced polarization and stored energy density. However, it also largely reduces the current leakage and energy loss of the resulting membranes, leading to significantly enhanced discharged energy density. It is believed that the strong interactions between PEO and SPI are responsible for the energy storage properties aforementioned. Meanwhile, such interactions also result in a more brittle fracture behavior and reduced crystallinity of the PEO/SPI membranes. The enhanced discharged energy density and low energy loss suggest PEO/SPI membranes are promising dielectric materials for high efficiency energy storage applications where soluble and transient materials are desired. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45214. [ABSTRACT FROM AUTHOR]

In this work, the poly(ethylene oxide) bulk as one example has been iteratively heated and cooled back using MD simulations to examine the effects of thermal history on the resulting T. It is demonstrated that, after the system is equilibrated once at the high temperatures, the simulated T does not exhibit a systematical shift with the thermal history, and the averaged T compares well with that for the single procedure, that is, adequately equilibrating at the highest temperature and cooling with the same rate to the lowest temperature. Additionally, the continuous and stepwise processes lead to almost identical T, density and volumetric expansive coefficients at both the glassy and rubbery states at 300 K and 1 atm. However, these results would somewhat vary with what (volume or density) are used and how to yield them. Furthermore, the stepwise processes allow one to obtain the time-dependent dynamical T values from the reorientation functions of the monomer vectors, which suggest greater differences within longer observation time. This work rationalizes the 'golden standard' procedure to simulate polymer T using the MD method, and provides some key clues to obtain the reliable results (specially for comparisons). [ABSTRACT FROM AUTHOR]

We propose a strategy to adjust the size of multiliposomal complexes made of small unilamellar anionic liposomes (lipid bilayer vesicles prepared from zwitterionic lipid 1,2-dioleoyl- sn -glycero-3-phosphocholine DOPC and ionic lipid 1-palmitoyl-2-oleoyl- sn -glycero-3-phospho- l -serine POPS with a typical diameter of 50 nm) with cationic polymers due to electrostatic attraction. Hereby, the use of quaternized poly(dimethylaminoethyl methacrylate), q PDMAEMA, allows the construction of multicompartmental carriers. Variation of the architecture and composition of various q PDMAEMA samples demonstrates the effect of introducing poly(ethylene oxide) PEO moieties and/or branching on the size of the hierarchical assemblies: both the PEO block (as seen for block copolymers and miktoarm stars) and the branching (as seen for star-shaped homopolymers and miktoarm stars) lead to smaller complexes compared to complexes with a linear q PDMAEMA homopolymer. Besides the use of cryogenic transmission electron microscopy (cryo-TEM), the formation of multicompartmental carriers composed of differently loaded liposomes is verified by two-color fluorescence cross-correlation spectroscopy (FCCS). [ABSTRACT FROM AUTHOR]

A facile fabrication of a porous carbon cryogel from a blend (PAEO) of fluorinated poly(amic acid) and poly(ethylene oxide) (PEO) is demonstrated. The porous carbons are prepared by carbonizing the freeze-dried cyrogels of polymer blend with various contents. The original channel structures of the cryogels with PEO content below 5 wt% are perfectly maintained in the carbon cryogels. In particular, the carbon cyrogel derived from the blend (PEO content: 5 wt%) shows very high specific surface areas, 2646 m 2 /g. From investigation of the carbonization mechanism, it is found that the incorporation of PEO creates mesoporous structure without generating hydrophobic or ambiphilic components, while elimination of fluorine moiety affects the formation of microporous structure in resulting-carbon. In addition, the porous structure in carbon cryogels of high PEO loading is shrunk because PEO component reduces the rigidity of the structure. Lastly, the performance of the carbon cryogels as a capacitor is investigated. [ABSTRACT FROM AUTHOR]

Chitosan (CS) is an excellent biocompatible natural antibacterial material that has attracted researchers to study its biological applications as artificial tissue scaffolds and wound-healing materials. In this research, CS has been mixed with polyethylene oxide (PEO) and mica at various weight ratios to prepare nanofibers; however, it is found to be a difficult task to prepare the nanofiber using pure CS. The composite in form of nanofibrous mat was prepared with CS/PEO solution and CS/PEO/mica solution using electrospinning. Processing conditions were adjusted to a flow rate of 6 ml/min, with an applied voltage of 27 kV. The distance of capillary tip to target was kept about 10 cm at 25°C with a collector having a speed of 200 rpm. The spinnability of solutions was also evaluated by using both plate and cylinder collectors. The composite mats were analyzed in detail using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermogravimetric analysis, and X-ray diffractogram (XRD). SEM photomicrograms indicated that the morphology and diameter of the nanofibers were affected by weight ratio of CS/PEO, concentration of mica, and types of collector. Furthermore, mica was incorporated in the CS/PEO matrix to enhance the specific surface area. Molecular interactions between CS/PEO and mica were investigated using FTIR and XRD. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) rapidly attracted a great attention as a potential material to be used in flexible rechargeable lithium ion batteries, if an optimal match between their ionic conductivity and mechanical stability was achieved. In this work, two types of nanocomposite SPE based on poly(ethylene) oxide (PEO) and lithium perchlorate salt (LiClO 4 ) containing pristine graphene (GnP) or polyethylene glycol-grafted graphene (FGnP) were prepared. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results revealed a reduced degree of crystallinity for nanocomposite electrolytes. The increment in amorphous phase domains was also confirmed by polarized optical microscope (POM), particularly for SPE/FGnP nanocomposites. Ionic conductivity showed one order of magnitude enhancement for SPE/FGnP(0.5%) at room temperature, while mechanical stability was also improved reasonably. Polyethylene glycol grafted onto FGnP appears to play two roles: plasticizing effect to promote the segmental motion of PEO chains, and contributing in dissociation of lithium salt. [ABSTRACT FROM AUTHOR]

Branched polymers are a valuable class of polymeric materials. In the present study, anionic polymerization techniques were employed for the synthesis of low molecular weight poly(ethylene oxide) (PEO) macromonomers bearing norbornenyl end groups. The macromonomers were characterized by SEC, MALDI-TOF and NMR spectroscopy. Subsequent ring opening metathesis polymerization (ROMP) of the macromonomers using ruthenium catalysts (Grubbs catalysts of the 1st, 2nd and 3rd generations) afforded the corresponding polymacromonomers. The effects of the macromonomer molecular weight, the type of the catalyst, the nature of the solvent, the monomer concentration and the polymerization temperature on the molecular characteristics of the branched polymers were examined in detail. The crystallization behavior of the macromonomers and the corresponding polymacromonomers were studied by Differential Scanning Calorimetry (DSC). The thermal stability and the kinetics of the thermal decomposition of the samples were also studied by Thermogravimetric Analysis (TGA). The activation energies of the thermal decomposition were analyzed using the Ozawa-Flynn-Wall and Kissinger methodologies. [ABSTRACT FROM AUTHOR]

The combined superimposing influences of the surface area of silica nano-particles and molecular weight of polyethylene oxide matrix on the rheological properties of suspensions have been studied. The parameters of both components varied over a wide range: the surface area of silica from 100 to 390 m/g, molecular weight of poly(ethylene oxide) from 200 to 2 × 10 Da, and concentration of silica from 1 to 13 vol%. In all cases, silica formed aggregates in suspension with apparent diameters of 50 to 230 nm; the higher values were observed for particles with larger surface area. Low-concentration suspensions in an oligomer matrix showed a slight non-Newtonian behavior; the size of silica particles was a determining parameter. Increasing the silica concentration led to dilatancy at high shear stresses. There was a threshold in the concentration dependence of viscosity, beyond which gelation of suspensions occurred. Depending on the silica concentration and molecular weight of the polymeric matrix, the dispersions behaved more like typical colloidal suspensions in a low molecular weight matrix or viscoelastic polymer melts containing an amount of solid filler. An increase in molecular weight of the polymeric matrix resulted in competition between increase in viscosity, appearance of viscoelasticity, and finally the transition from the gel state of a suspension in viscous medium to an elastic fluid. [ABSTRACT FROM AUTHOR]

In this work, the wool keratin/polyethylene oxide (PEO) nanofibers used for air filtration were prepared and characterized. Keratin proteins were first extracted from wool fibers by sulphitolysis, and then blended with PEO to improve the processability of keratin. Keratin/PEO nanofibers were produced by the electrospinning of the blend aqueous solutions. The rheological and conductive characteristics of the keratin/PEO blend solutions were studied, and correlated with the morphological and structural properties of the electrospun nanofiber membranes. Furthermore, the keratin/PEO nanofiber membranes were composited with polypropylene nonwoven fabric with the aim of being used as filtration materials. The observations by scanning electron microscopy showed that the morphological structures and diameter distributions of the keratin/PEO nanofibers were affected by the content of keratin. The filtration tests revealed that the filtration efficiency of the nanofiber nonwoven composites was greatly higher than that of polypropylene nonwoven fabric, and increased with the prolongation of electrospinning time. This study points out that keratin/PEO nanofibers can be used as promising materials for air filtration. [ABSTRACT FROM AUTHOR]

Water-soluble polymers with high molecular weights are known to decrease the frictional drag in turbulent flow very effectively at concentrations of tens or hundreds of ppm. This drag reduction efficiency of water-soluble polymers is well known to be closely associated with the flow conditions and rheological, physical, and/or chemical characteristics of the polymers added. Among the many promising polymers introduced in the past several decades, this review focuses on recent progress in the drag reduction capability of various water-soluble macromolecules in turbulent flow including both synthetic and natural polymers such as poly(ethylene oxide), poly(acrylic acid), polyacrylamide, poly(N-vinyl formamide), gums, and DNA. The polymeric species, experimental parameters, and numerical analysis of these water-soluble polymers in turbulent drag reduction are highlighted, along with several existing and potential applications. The proposed drag reduction mechanisms are also discussed based on recent experimental and numerical researches. This article will be helpful to the readers to understand better the complex behaviors of a turbulent flow with various water-soluble polymeric additives regarding experimental conditions, drag reduction mechanisms, and related applications. [ABSTRACT FROM AUTHOR]

Rechargeable magnesium batteries provide the potential for lower cost and improved safety compared with lithium-ion batteries, however obtaining cathode materials with highly reversible Mg-ion capacities is hindered by the high polarizability of divalent Mg-ions and slow solid-state Mg-ion diffusion. We report that incorporating poly(ethylene oxide) (PEO) between the layers of hydrated vanadium pentoxide (V 2 O 5 ) xerogels results in significantly improved reversible Mg-ion capacities. X-ray diffraction and high resolution transmission electron microscopy show that the interlayer spacing between V 2 O 5 layers was increased by PEO incorporation. Vibrational spectroscopy supports that the polymer interacts with the V 2 O 5 lattice. The V 2 O 5 -PEO nanocomposite exhibited a 5-fold enhancement in Mg-ion capacity, improved stability, and improved rate capabilities compared with V 2 O 5 xerogels. The Mg-ion diffusion coefficient of the nanocomposite was increased compared with that of V 2 O 5 xerogels which is attributed to enhanced Mg-ion mobility due to the shielding interaction of PEO with the V 2 O 5 lattice. This study shows that beyond only interlayer spacing, the nature of interlayer interactions of Mg-ions with V 2 O 5 , PEO, and H 2 O are key factors that affect Mg-ion charge transport and storage in layered materials. The design of layered materials with controlled interlayer interactions provides a new approach to develop improved cathodes for magnesium batteries. [ABSTRACT FROM AUTHOR]

A solid polymer electrolyte ( SPE) was prepared via a solution casting method from a blend of equal weight fractions of poly(ethylene oxide) ( PEO) and succinonitrile, used as the polymer matrix, and a salt, Li( CF3SO2) 2N ( x = 0-0.3 in weight fraction). A plot of the electrical conductivity (σ25°C) vs. x showed an upturned U-shape, with the highest value being ~3.9 × 10−4 S/cm for x = 0.25 ( EO/Li+ = 9.8; the optimum conducting composition). The electrolytes with x ranging from 0.15 to 0.3 showed a linear trend in their log(σ T0.5) − ( T− To)−1 curves with low pseudo-activation energy values, suggesting the presence of highly conductive amorphous domains, as confirmed by X-ray diffractometry measurements, Fourier-transform infrared ( FT-IR) spectroscopy, polarized optical microscopy, and differential scanning calorimetry studies. The change in PEO chain conformation with x is discussed in detail using FT-IR spectroscopy in the light of earlier results reported for PEO − Li( CF3SO2) 2N SPEs. [ABSTRACT FROM AUTHOR]

Polymer electrolytes comprising LiN(CF 3 SO 2 ) 2 salt (LiTFSI) and high molecular weight poly(ethylene oxide) PEO are prepared by casting from solution. A wide range of salt concentration is studied, from molar ratio EO:Li of 50:1 to 1.5:1. Samples of electrolytes are measured in symmetrical Li|electrolyte|Li cell. The values of lithium transference number t + of electrolytes are determined using a novel procedure, which involves impedance spectroscopy as well as two potentiostatic polarization segments with opposite sign of d.c. bias. The principles of this procedure are based on Bruce-Vincent method, which has been extended in order to compensate the possible differences in properties of the two Li|electrolyte interfaces, and ensure proper conditioning of the cell between different stages of the measurement process. The results are analyzed using Bruce-Vincent and Watanabe approaches, which give similar values of lithium transference number. The reported values of t + initially decrease with rising concentration of salt, but after passing a minimum at molar ratio EO:Li of around 6:1, a considerable increase is recorded, eventually leading to lithium transference number higher than 0.5 for “polymer in salt” systems. Such behavior of the studied system is discussed either in terms of formation of PEO:salt complexes, or formation of ionic aggregates. [ABSTRACT FROM AUTHOR]

N-type semiconducting molybdenum trioxide (MoO 3 ) nanoparticles embedded in polyethylene oxide (PEO) polymer ultra-fine fibres were deposited directly onto silicon substrates using an electrospinning technique. The effects of different MoO 3 /PEO concentrations as well as electrospinning parameters on the fibre morphologies were examined. Experimental results show that embedding nanoparticles and electrospinning onto small areas can be achieved without use of solvents or transfer of the deposited nanostructures. This approach offers a cost effective fabrication method to produce a diverse range of multifunctional materials for many applications including electronics, mechanical enhancement, drug delivery and gas sensing. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide)/lithium montmorillonite (PEO/LiMMT) nanocomposites were prepared by melt intercalation method. The degradation of PEO/LiMMT nanocomposites was performed by non-isothermal thermogravimetry in nitrogen atmosphere at four heating rates (2.5, 5, 10 and 20 °C min). The obtained data were used for the kinetic analysis of the degradation process. Kinetic analysis was performed using the isoconversional Friedman method in combination with the multivariate nonlinear regression method. Kinetic analysis revealed the complexity of the thermal degradation process for both pure PEO and all PEO/LiMMT nanocomposites. The contribution of the each individual degradation stage was determined, and each of them was independently analyzed. Kinetic parameters (activation energy, pre-exponential factor and kinetic model) were also calculated for each degradation stage of all investigated samples. [ABSTRACT FROM AUTHOR]

The influence of poly(ethylene glycol) (PEG) on thermal characteristics and thermal degradation of poly(vinyl chloride)/poly(ethylene oxide) (PVC/PEO) blends was investigated by differential scanning calorimetry and dynamic thermogravimetry. The thermal degradation characteristics of PEO remain unchanged upon PEG addition, while for all other investigated blends their values decreased, particularly at higher PVC content. Kinetic analysis of the non-isothermal degradation of investigated PVC/PEO/PEG blends was performed using isoconversional Friedman method in combination with the multivariate nonlinear regression method. The PEG addition lowers the values of the activation energies of PVC/PEO blends. The kinetic analysis indicated four-stage degradation mechanism for all investigated blends. [ABSTRACT FROM AUTHOR]

The ever-increasing energy demand led scientists turn to more efficient, environmentally friendly, and renewable technologies. Phase change materials (PCMs) are gaining popularity in the field of passive thermal energy storage. In the current work, polyethylene oxide/poly (methyl methacrylate) (PEO/PMMA) electrospun fibers were employed as encapsulation matrices for n-eicosane and their physicochemical properties were tested, aiming to develop stable phase change fibers (PCFs). The effect of the n-eicosane content on the morphology and thermal properties of the form-stable PEO/PMMA/n-eicosane PCFs was extensively investigated by using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). The melting and crystallization enthalpy of PEO/PMMA/n-eicosane remained unchanged during the first and second cycle. After 30 heating-cooling cycles, the samples with 2 and 5 wt% n-eicosane exhibited inferior thermal reliability, while no temperature and enthalpy change were observed after the thermal cycling of PCF with 7.5 and 10 wt% n-eicosane content, thus rendering these systems suitable materials for thermal energy storage applications. The most promising system was the one containing a 10 wt% n-eicosane, due to the higher crystallization enthalpy (184 J/g) and the stabilization of the melting and crystallization peaks for all cycles. The degradation kinetics were investigated for n-eicosane, the pristine PEO/PMMA fibers and the PEO/PMMA/n-eicosane fibers with a 10 wt% n-eicosane content. Moreover, the Activation Energy (E a) and the pre-exponential factor (A) were calculated using the Friedman and Vyazovkin methods whereas the reaction mechanisms were studied using the model fitting method. [Display omitted] • Fabrication of electrospun form-stable n-eicosane-based phase change fibers (PCF). • High crystallization enthalpy (184 J/gr) for the system with 10% wt. n-eicosane. • High thermal reliability and low supercooling values. • Thermal degradation kinetics performed on n-eicosane, pristine fibers and PCF. [ABSTRACT FROM AUTHOR]

Electrical conductive poly(methyl methacrylate) (PMMA) nanocomposites with low percolation threshold are very challenging to be prepared. Here, we show that the miscibility between poly(ethylene oxide) (PEO) as matrix for predispersions of multi-walled carbon nanotubes (MWCNTs) and PMMA represents an efficient approach to achieve very low electrical percolation threshold. PMMA/PEO-MWCNTs nanocomposites were prepared by a two-step solution casting method involving pre-mixing of MWCNTs with PEO and then mixing of PEO-MWCNTs with PMMA, resulting in a PMMA/PEO ratio of 80/20 wt%. The electrical percolation threshold (EPT) value was determined to be ~ 0.07 wt% which is significantly lower than most of the reported EPT values in the literature for PMMA/CNT composites. The very low electrical percolation threshold was attributed to the effectual role of PEO in self-assembly of secondary structures of nanotubes into an electrically conductive network. This was further confirmed by transmission electron microscopy and by comparing the obtained EPT value with the prediction of the excluded volume model in which statistical percolation threshold is defined based on uniform distribution of high-aspect ratio sticks in a matrix. Moreover, based on UV–Vis measurements and linear viscoelastic rheological measurements, optical and rheological percolation thresholds were obtained at nearly 0.01 wt% and 0.5 wt%, respectively. [ABSTRACT FROM AUTHOR]

We developed highly promising solid polymer electrolytes (SPEs) based on a novel cross-linker containing star-shaped phosphazene with poly(ethylene oxide) (PEO) branches with very high ionic conductivity (7.6 × 10 −4 S cm −1 ), improved mechanical stability, and good electrochemical stability for all-solid-state lithium batteries. In particular, allyl groups were introduced at the ends of the cross-linker in order to overcome the easy self-polymerization of existing cross-linking acrylate end groups. A novel semi-interpenetrating network (semi-IPN) SPE was prepared by in-situ radical polymerization of a precursor solution containing lithium salt, poly(ethylene glycol) dimethyl ether as a plasticizer, and a mixture of pentaerythritol tetrakis(3-mercaptopropionate) and a synthesized hexakis(allyloxy)cyclotriphosphazene ( thiol-ene PAL) as the cross-linker. Batteries employing LiFePO 4 as the cathode, lithium foil as the anode, and the SPE thin film as the electrolyte were assembled and tested. At ambient temperature, the initial discharge capacity was 147 mAh/g at 0.1 °C and 132 mAh/g at 0.5 °C, and 97% of the capacity was retained at the 100th cycle. All-solid-state pouch-package lithium cells assembled with the SPEs exhibited stable electrochemical performance, even under a severely wrinkled state. These outstanding properties of SPEs based on thiol-ene PAL demonstrate feasibility for practical battery applications with improved reliability and safety. [ABSTRACT FROM AUTHOR]