PEO Composition Research Articles

Insights into in-situ synthesis of PEO-LDH composite film on AM50 Mg alloy: The effect of final voltage

MgAl layered double hydroxide (LDH) layer was in-situ grown on PEO coatings formed at different voltages. Influence of thickness, phase composition and stability of the initial PEO coating on LDH formation was investigated. A PEO layer consisting of thin and unstable amorphous phase can be recrystallized into LDH, while a dense coating slows down LDH growth. Balancing the dissolution of the PEO structure with formation of LDH nanocontainers can dramatically enhance the corrosion resistance of the resultant coating. The superior corrosion properties can be attributed to the intact parent PEO layer, the uniform coverage of the LDH film and its ion-exchange effect.

Fast Magnesium Conducting Electrospun Solid Polymer Electrolyte

AbstractMagnesium Ion based Solid State Batteries (MIBs) are subject of intensive studies due to abundance of magnesium, its advantages in volumetric capacity, and the reduced dendrite growth. Here we report on a true solid polymer electrolyte system without liquid additives or plasticizers that reaches conductivities above 10−5 S cm−1 at room temperature and above 10−4 S cm−1 at 50 °C. An electrospun polymer electrolyte membrane fabricated from a polymer electrolyte featuring a composition of PEO : Mg(TFSI)2 36 : 1 [where PEO stands for poly(ethyleneoxide) and Mg(TFSI)2 for magnesium bis(trifluoromethanesulfonyl) imide] was identified as the best performing system. Magnesium transport was substantiated by different methods, and the electrochemical properties including solid electrolyte interface (SEI) formation were investigated. Electrospinning as a preparation method has been identified as a powerful tool to enhance the electrochemical properties beyond conventional polymer membrane fabrication techniques.

Facile and Green Synthesis of Silver Quantum Dots Immobilized onto a Polymeric CTS-PEO Blend for the Photocatalytic Degradation of p-Nitrophenol.

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal–polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan–polyethylene oxide (CTS–PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS–PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS–PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS–PEO composites by the interactions and complexation between x wt % Ag QDs and CTS–PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS–PEO blend sheets, indicating the immobilization of Ag QDs onto CTS–PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS–PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS–PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS–PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS–PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

Effect of nanostructured Al2O3 on poly(ethylene oxide)-based solid polymer electrolytes

Abstract In this study, we investigated the effect of nanostructured Al2O3 particles on Li ion conducting, poly(ethylene oxide) (PEO)-based membranes prepared by electrospinning, solution casting and hot pressing. Pure PEO:LiBF4 solid polymer electrolytes (SPEs) and also plasticizer containing membranes were investigated with various amounts of Al2O3. In a first step, the best-performing composition of pure PEO:LiBF4 concerning the resulting ionic conductivity was identified and used as a standard for further experiments. In the following, the influence of the preparation method, the nature of the Al2O3, and the type of the plasticizer additives on the thermal and electrochemical properties for this standard composition were investigated. The Al2O3 composition was varied between 1 and 5 wt%. The ionic conductivity of bare electrospun PEO:LiBF4 SPE standard material has been improved by a factor ten to 1.9 × 10−6 S cm−1 at T = 293 K when 5 wt% of Al2O3 is added. For solution-casted PEO:LiBF4 standard compositions 18:1 with an initial ionic conductivity of 6.7 × 10−8 S cm−1, the addition of 2 wt% Al2O3 increased the performance to 1.4 × 10−7 S cm−1, both at T = 293 K. If succinonitrile and Al2O3 was admixed to the solution casted standard material, the ionic conductivity was further increased to reach 5.5 × 10−5 S cm−1 at T = 293 K. This material with a composition of 18:3:1 + 2 wt% Al2O3, outperforms the standard material by three orders of magnitude.

Effect of Environmental Conditions on the Yield of Peel and Composition of Essential Oils from Citrus Cultivated in Bahia (Brazil) and Corsica (France)

The cosmetic and fragrance industry largely exploits citrus essential oils (EOs) because of their aromatic properties. EO compositions are complex and differ between fruit pericarp (PEO) and leaf (LEO). Citrus fruit grow in many countries under very different climates. Seventeen citrus cultivars were selected and their similarities between the two collections were verified by SSR (Single Sequence Repeat) and InDel (Insertion and Deletion) markers to assess the effects of the environment and cultivation practices on the EO yield and composition. LEOs and PEOs were extracted by water distillation and analyzed by GC-MS. PEO yields were generally higher in Corsica than in Bahia, especially in the citron family. PEOs in this family were richer in limonene in Bahia than in Corsica while, conversely, neral, geranial and derivatives were present in a higher proportion in Corsican varieties. A few minor components were site-specific, such as nookaton, a pummelo-specific compound that was not present in grapefruit cultivated in Bahia. If climate change over the last 20 years has not affected the PEO composition in Corsica, the contrasted environmental conditions and cultural practices between Bahia and Corsica could possibly explain the EO variations.

Well-aligned BaTiO3 nanofibers via solution blow spinning and their application in lithium composite solid-state electrolyte

In this work, an efficient and simple solution blow spinning method for preparing well-aligned nanofibers was proposed. Compared with common electrospinning, this method is more promising for scalable fabrication because of fewer process requirements. Through this method, well aligned BaTiO3 nanofibers were fabricated, and their average diameter was about 300 nm. When introducing PEO and LiTFSI ionic conductive polymer composites into the aligned BaTiO3 nanofibers membrane, a composite solid-state polymer electrolyte was obtained. The excellent structure for the electrolyte was also analyzed and its electrochemical performance was tested. Results showed that the lithium ionic conductivity at 30 °C increased from 5.74 × 10–6 S · cm–1 to 5.83 × 10–5 S · cm –1 with addition of aligned BaTiO3 nanofibers, and its thermal and electrochemical stability were all significantly improved.

Preparation, structure, and properties of poly(ethyleneoxide)/lignin composites used for UV absorption

ABSTRACTA composite of poly(ethylene oxide) (PEO) and lignin (Lg) was prepared and characterized for its utility as an ultraviolet (UV) absorbing material. Due to the extensive UV absorption and excellent oxidation‐resistance of Lg, the formation of hydrogen bonds between the Lg particles and the PEO molecular segments renders the Lg particles well‐dispersed in the PEO matrix. PEO/Lg composites with different Lg contents show that high levels of Lg could cause defects at the PEO/Lg composite interface. The viscosities of all composites were higher than that of pure PEO. Composite foams were further prepared under supercritical carbon dioxide conditions, all of which exhibited excellent UV‐absorption properties. This work provides a means toward convenient preparation of PEO composites with UV‐absorption ability and forms a theoretical basis for the dispersion of Lg in polymer matrices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48593.

Role of adsorbed chain rigidity in reinforcement of polymer nanocomposites

ABSTRACTThe thermomechanical behavior of polymer nanocomposites is mostly governed by interfacial properties which rely on particle–polymer interactions, particle loading, and dispersion state. We recently showed that poly(methyl methacrylate) (PMMA) adsorbed nanoparticles in poly(ethylene oxide) (PEO) matrices displayed an unusual thermal stiffening response. The molecular origin of this unique stiffening behavior resulted from the enhanced PEO mobility within glassy PMMA chains adsorbed on nanoparticles. In addition, dynamic asymmetry and chemical heterogeneities existing in the interfacial layers around particles were shown to improve the reinforcement of composites as a result of good interchain mixing. Here, the role of chain rigidity in this interfacially controlled reinforcement in PEO composites is investigated. We show that particles adsorbed with less rigid polymers improve the mechanical properties of composites. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2019,57, 9–14

Unexpected Phase Behavior of Pluronic Polymer-Organic Derivative Mixtures Depending on Temperature in Aqueous Solution.

The phase behavior of amphiphilic Pluronic block copolymers in aqueous solution is of importance for a broad spectrum of practical applications but has not been fully exploited yet. Here, the phase behavior of the mixture of the Pluronic P65 and P105 triblock copolymer, (which have the same composition of PEO and PPO but the different molecular weight) and organic derivative, 5-methyl salicylic acid (5mS), in aqueous solution has been investigated by using small angle neutron scattering (SANS). According to the temperature and the 5mS concentration, SANS measurements showed that the P65-5mS mixtures sequentially transform into a random coil, sphere, vesicle, cylinder, and vesicle again, while the P105-5mS mixtures form spherical particles with two different sizes without any topological phase transition. Upon heating, the formation of two different kinds of the vesicle structure of amphiphilic block copolymer in aqueous solution is very unusual. This phase behavior was explained as the coupled effect of the simultaneous increase of the hydrophobicity of the polymer and the solubility of 5mS molecules upon heating. This result gives fundamental information for the practical use of Pluronic polymers in nano- and bio-science and it provides a simple route for the fabrication of the nanostructure without a complicated procedure.

Research on the improvement of mixed titania and Co(Mn) oxide nano-composite coatings

The structure and the properties of the oxide films formed on titanium in the diphosphate based electrolytes by means of plasma electrolytic oxidizing at direct current density of 2–2.5 A·dm−2 have been studied. Oxide layers of different composition and content of alloying elements were obtained by modification of electrolytes and variation in current density. The interelectrode voltage during PEO, chemical and phase composition, topography and microstructure of the formed layers depend on the electrolyte composition and applied current density. The spark-discharge regime was shown to be reached at inter-electrode voltage 100 to 130 V depending on the composition of electrolyte. The effect of chemical composition and surface morphology formed mixed oxide films on the corrosion resistance and catalytic activity has been discussed.

A Facile Methodology for the Development of a Printable and Flexible All-Solid-State Rechargeable Battery.

Development of printable and flexible energy storage devices is one of the most promising technologies for wearable electronics in textile industry. The present work involves the design of a printable and flexible all-solid-state rechargeable battery for wearable electronics in textile applications. Copper-coated carbon fiber is used to make a poly(ethylene oxide) (PEO)-based polymer nanocomposite for a flexible and conductive current collector layer. Lithium iron phosphate (LiFePO4) and titanium dioxide (TiO2) are utilized to prepare the cathode and anode layers, respectively, with PEO and carbon black composites. The PEO- and Li salt-based solid composite separator layer is utilized for the solid-state and safe electrolyte. Fabrication of all these layers and assembly of them through coating on fabrics are performed in the open atmosphere without using any complex processing, as PEO prevents the degradation of the materials in the open atmosphere. The performance of the battery is evaluated through charge-discharge and open-circuit voltage analyses. The battery shows an open-circuit voltage of ∼2.67 V and discharge time ∼2000 s. It shows similar performance at different repeated bending angles (0° to 180°) and continuous bending along with long cycle life. The application of the battery is also investigated for printable and wearable textile applications. Therefore, this printable, flexible, easily processable, and nontoxic battery with this performance has great potential to be used in portable and wearable textile electronics.

Enhanced Magnesium-Ion Charge Transport and Storage within Layered Vanadium Pentoxide-Poly(ethylene oxide) Nanocomposites

Cathode materials that have high reversible magnesium-ion capacities and reasonable operating voltages are needed for rechargeable magnesium batteries. Layered materials are a particularly promising class of materials for electrochemical Mg-ion charge storage, however additional research is needed to increase Mg-ion capacities, improve capacity retension upon cycling, and understand the nature of interlayer interactions. Our work has investigated hydrated vanadium pentoxide (V2O5) xerogels that incorporate poly(ethylene oxide) (PEO) between the layers as an approach to improve Mg-ion charge storage and control interlayer structure and dynamics. V2O5 nanosheets were grown in the presence of PEO to allow inimate interaction with the V2O5 layers and allow control of the PEO content in V2O5-PEO nanocomposites. X-ray diffraction and high resolution transmission electron microscopy demonstrate that the interlayer spacing between V2O5 layers was increased by incorporating PEO within the layers. The Mg-ion diffusion coefficient was shown to be strongly dependent on not only interlayer spacing, but also interlayer composition. With specific polymer compositions, Mg-ion diffusion within V2O5-PEO nanocomposites was significantly increased compared with V2O5 xerogels. Raman spectroscopy supports that the polymer interacts with the V2O5 lattice resulting in interlayer water that is less strongly bound to the V2O5 lattice. The V2O5-PEO nanocomposite with specific PEO compositions exhibited significantly improved Mg-ion specific capacity compared with V2O5 xerogels and showed improved capacity retension upon cycling. Our work supports that in addition to interlayer spacing, controlling interlayer interactions between V2O5 layers, PEO, H2O, and Mg-ions allows significant improvements in Mg-ion charge transport and storage. The design of layered materials with controlled interlayer compositions provides a novel route to significantly improve charge storage and transport in layered materials.

Using depolarized light intensity to study the crystallization and degradation behavior of poly(l-lactic acid) and its blends with poly(ethylene oxide)

The crystallization and degradation behaviors of poly(l-lactic acid) (PLLA) and its blends with poly(ethylene oxide) (PEO) were investigated by depolarized light intensity (DLI). It was found that DLI is sensitive to study the degree of order in polymer thin film samples. The growth rate of the PLLA spherulites was increased by blending up to 80 % PEO, as it increased the chain mobility in the blend melts. At larger PEO compositions (i.e., 90 % PEO), the dilution effect dominates and the PLLA growth rate was retarded. Three distinct blend groups with respect to the blend composition were proposed: (1) 10–20 wt% PEO in which the PEO is not able to form any ordered structure in the binary blend; (2) 30–50 wt% PEO in which the PEO is able to form some order but not enough to develop spherulitic crystals; (3) 60–90 wt% PEO in which the PEO forms a network of spherulites throughout the pre-crystallized PLLA.

Preparation and Characterization of Surfactant-Modified Powder Activated Carbon (SM-PAC) Reinforced Poly (Ethylene Oxide) (PEO) Composites

Poly (ethylene oxide), PEO, which was used for a wide variety of applications is a flexible, crystalline, thermoplastic, water-soluble and non-ionic polymer. The most of studies on surfactant-modified activated carbon (SM-PAC) have been generally focused on the removal of contaminants. This study aims the preparation of PEO/(SM-PAC) composites, using solution-intercalation method. Firstly activated carbon was modified with cationic surfactant, Cetyltrimethylammonium Bromide (CTAB). Then PEO/(SM-PAC) composites were prepared using solution-intercalation method, with two different (SM-PAC) contents (1.0 and 2.0 wt.%). The characterization of the composites was made by X-ray diffraction (XRD), Fourier Infrared Spectroscopy (FT-IR), thermal analysis and tensile tests. The XRD patterns revealed that 2θ positions of the broad peaks belonging to the composites significantly shift to left compared with those of virgin PEO. The SEM images of the surfactant-modified powdered activated carbon (SM-PAC)/PEO composites prepared with the two different SM-PAC contents show that there is an intensive interaction between the CTA ions of modified activated carbon surface and the polymer chains. From the tensile tests, it was found that the unmodified powdered activated carbon dispersed into the polymer matrix made the ductile polymer more brittle. However, the tensile and yield strengths of the composite, prepared with modified powdered activated carbon, have decreased, and the strain percent value has significantly increased.

Dual Nafion/Polyaniline Nanofibers Architecture for Applications in Fuel Cells Electrodes

We demonstrate a facile route for fabrication of nanostructured fuel cell cathode catalyst support via simultaneous co-electrospinning of electron and proton conducting materials. Solutions of Nafion and polyaniline (PANI) were electrospun simultaneously from two separate nozzles on a common substrate with the aim to develop co-percolating electron and proton conducting pathways. Owing to the lack of entanglements in Nafion and PANI solutions, PEO was used to aid in electrospinning of both solutions. The composition of the dual nanofiber mat was tailored by varying the relative solution concentrations and flow rates. SEM micrographs (fig.1 (a)) of the mats show three-dimensional porous non-woven morphology, which is ideal for facile gas transport and also for enhancement of the triple phase surfaces. Electrochemical impedance spectroscopy show presence of independent charge transfer channels in the composite fiber mats (fig.1 (b)). Equivalent circuits were used to decouple electrical conductivity from protonic conductivity. Electrical conductivity was also verified via current/voltage (I-V) curves. Dual fiber mat with a Nafion/PANI/PEO composition of 50/32/18 showed proton conductivity of 0.032 S/cm and electron conductivity of 0.042 S/cm. Such proton conductivity was shown to be higher than the pure Nafion (with 2wt% PEO as the carrier polymer) nanofiber mat. The dual fiber mat also showed the highest water intake capacity (presumably due to its high composition of the hydrophilic PEO), which we believe is responsible for its higher proton conductivity. Such dual fiber mats with percolating phases of both electron and proton conductors and a three dimensional through–connected inter-fiber pore structure (for gas transport) can serve as an excellent catalyst support for PEMFCs. Figure 1 Nanofiber mat with a Nafion/PANi/PEO weight composition of 50/32/18 (a): SEM micrograph, Scale bar; 1µm, b) Nyquist plot showing experimentally-obtained data and fitted impedance data obtained via an equivalent circuit. Figure 1

Effects of top confinement and diluents on morphology in crystallization of poly(l‐lactic acid) interacting with poly(ethylene oxide)

ABSTRACTEffects of top confinement and diluent poly(ethylene oxide) (PEO) on poly(l‐lactic acid) (PLLA) crystal morphology have been investigated. When crystallized at 120 °C, uncovered neat PLLA sample exhibits higher growth rate ringless spherulites; while the covered sample exhibits lower growth rate ring‐banded spherulites. As PEO is introduced into PLLA, the morphology also undergoes significant changes. For the same Tc,PLLA = 120 °C, the PEO/PLLA blend with PEO composition greater than 25% exhibits ring‐banded patterns even in uncovered sample. However, in much greater PEO composition (>80 wt %), uncovered samples exhibit ring bands diverging into dendritic patterns, while top covered samples tend to maintain the spiral ring‐band patterns. Both PEO inclusion in PLLA and top cover on films impose growth kinetic alterations. Additionally, the top glass cover tends to prevent the lower surface tension PLLA to be accumulated on the surface, resulting in the formation of ring‐band pattern. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1160–1170

STUDY OF CHARACTERIZATION OF (PEO+KCLO4) POLYMER ELECTROLYTE SYSTEM

Solid state polymer electrolytes have been prepared by using poly (ethylene oxide) (PEO) and KClO4 salt in the Wt% ratios of (90:10), (80:20) and (70:30) by solution – casting technique by using methanol (water-free) as solvent. The complexation of pure PEO with KClO4 salts has been extensively studied using IR studies. In the Differential Scanning Calorimetry (DSC) curves it observed that, pure PEO melting temperature (Tm) slight shift towards lower temperature is due to the addition of KClO4 salt to the polymer. XRD data for these films clearly confirm the complexation between the KClO4 salt and the polymer PEO. The d-values calculated from the X-ray diffraction of pure PEO and various compositions of KClO4 complexed films are clearly indicate the complexation of PEO and KClO4.

Disclosing the formation of ring-banded spherulites for semicrystalline polymers through the double-layer film method

The formation of ring-banded spherulites in double-layer semicrystalline polymer films has seldom been a concern. In this study, the nucleation and growth of ring-banded spherulites in poly(ethylene oxide)/poly(L-lactide) (PEO/PLA) double-layer films during isothermal crystallization at various temperatures above the melting point of the PEO layer have been investigated by using polarized optical microscopy (POM). The sequential crystallization of PLA and PEO components in the double-layer films was confirmed by a double quench crystallization procedure. The surface morphologies of ring-banded spherulites were examined by using scanning electron microscopy. The experimental results are compared with those for PLA/PEO blend films with 25 wt% PEO composition. It is interesting to find that the changing trend of band space in ring-banded spherulites at different isothermal crystallization temperatures in PEO/PLA double-layer films is more complex than that in PLA/PEO blend films. For the former ones, the ring-banded spherulites form at the lowest temperature approaching 65 °C and the band space slightly increases from 65 to 90 °C, is absent from 90 to 105 °C, obviously decreases from 105 to 115 °C, and significantly increases from 115 to 135 °C. For the latter ones, the band space only shows a monotonic increase with increasing temperature at above 105 °C. The mechanism for the formation of ring-banded spherulites in the PEO/PLA double-layer film system is proposed. The experimental results may shed some light on explaining the formation mechanism of ring-banded spherulites in semicrystalline polymers.

Synthesis of monolithic zirconia with macroporous bicontinuous structure via epoxide-driven sol–gel process accompanied by phase separation

Monolithic macroporous zirconia was synthesized through a new method involving an epoxide-driven sol–gel method accompanied by a spontaneous phase separation. The sol–gel transition utilized inorganic salt ZrCl4 as primary precursor and propylene oxide as matrix former through a ring-opening reaction. Phase separation was induced with poly-(ethylene oxide) (PEO) and its tendency was adjusted by incorporating Mg2+/Y3+ and N-methylformamide (NFA) in starting solution. The morphology of the dried gel changed from a solid nanoporous structure through a phase separated macroporous bicontinuous structure to aggregates particles when varying Mg2+ or Y3+, NFA and PEO composition. An appropriate choice of the starting composition, by which the phase separation and gelation occurred parallel, allows the fabrication of macroporous zirconia monoliths in large dimensions (Φ = 30 mm, h = 8 mm). The skeleton of the monolithic macroporous zirconia gels possess a BET surface area of 271.7 m2/g. Accordingly, the effect and mechanisms of Mg2+, Y3+ and NFA during gelation process were proposed in detail. Moreover, Mg2+ or Y3+ might also act as stabilizer to form the magnesia or yttria stabilized tetragonal or cubic zirconia after the samples were heat-treated at high temperature (800 °C).

Core–Shell Structured PEO-Chitosan Nanofibers by Coaxial Electrospinning

Core-shell structured PEO-chitosan nanofibers have been produced using a coaxial electrospinning setup. PEO and chitosan solutions, both in an aqueous acetic acid solvent, were used as the inner (core) and outer (shell) layer, respectively. Uniform-sized defect-free nanofibers of 150-190 nm diameter were produced. In addition, hollow nanofibers could be obtained subsequent to PEO washing of the membranes. The core-shell nanostructure and existence of chitosan on the shell layer were confirmed by TEM images obtained before and after washing the PEO content with water. The presence of chitosan on the surface of the composite nanofibers was further supported by XPS studies. The chitosan and PEO compositions in the nanofibrous mats were determined by TGA analysis, which were similar to their ratio in the feed solutions. The local compositional homogeneity of the membranes and the efficiency of the washing step to remove PEO were also verified by FTIR. In addition, DSC and XRD were used to characterize the crystalline structure and morphology of the co-electrospun nonwoven mats. The prepared coaxial nanofibers (hollow and solid) have several potential applications due to the presence of chitosan on their outer surfaces.