Polyethylene Oxide Films Research Articles

The effect of garnet content on the microstructure and electrochemical properties of PEO/garnet composite electrolyte

Solid-state lithium-metal batteries are one of the best candidates for next-generation energy storage devices. However, their applications are hindered by the low ionic conductivity at room temperature and the inadequate interfacial compatibility of solid-state electrolytes (SSEs). Hence, an organic/inorganic composite solid electrolyte (CSE) of Li6.25Ga0.25La3Zr2O12 (LGLZO)/polyethylene oxide (PEO) films were constructed. It's found that the crystallinity of CSE is significantly reduced and the ionic conductivity is increased to 3.57 × 10−4 S cm−1 at room temperature, which is about 60 times higher than that of the pure PEO.And the interfacial impedance is 243.84 Ω cm2, electrochemical window of 5.1 V. The assembled Li symmetric battery has excellent cycling stability more than 1000 h at 0.15 mA cm−2. The Li/PEO-LiTFSI-60 wt% LGLZO/LiFePO4 (LFP) all solid-state lithium batteries (ASSLBs) also delivers superior electrochemical performances. This work can provide a reference for the development and real-world implementation of ASSLBs at room temperature.

Optical, electrical, and structural properties of polyethylene oxide/fullerene nanocomposite films

Polyethylene oxide (PEO)/fullerene (C60) nanocomposite films were synthesized through a solution mixing and casting method. The influence of increasing C60 concentration on thermal stability is evident in thermogravimetric analysis (TGA) profiles. TGA is employed to assess the thermal stability of polyethylene oxide (PEO) films, revealing a gradual weight loss below 200°C and pronounced degradation between 200°C and 500°C. PEO films doped with C60 improve their stability, with the 8 wt% C60 film retaining 40 wt% of its initial weight at 425°C—four times greater than the 1 wt% C60 film. XRD patterns exhibit a progressive reduction in crystallinity, decreasing from 52% to 38% with higher C60 content. Furthermore, C60 introduction leads to a reduced transmittance in the visible region, a redshift in the band edge, indicative of decreasing bandgap energy from 3.95 eV to 3.59 eV. Overlapping absorption bands in the extinction coefficient spectra (490 nm–620 nm) corresponded to π-π* and n-π* transition bands of C60. The electrical conductivity of PEO/C60 nanocomposite films demonstrate a substantial increase directly proportional to C60 concentration, reaching approximately 200-fold the conductivity of undoped PEO (2.28 × 10−6) at 8 wt% (1.11 × 10−4 S cm−1).

Enhanced radiative cooling with Janus optical properties for low-temperature space cooling

Abstract Passive daytime radiative cooling that could provide sub-ambient cooling emerges as a promising technology to reduce household energy consumption. Nonetheless, prevailing studies are predominantly focused on surface cooling, often overlooking its adaptability to enclosed spaces with active cooling technologies. Here we present a multilayer radiative cooling film (J-MRC) with Janus optical properties in the mid-infrared region, consisting of the nanoporous polyethylene films, the polyethylene oxide film, and silver nanowires. The top side of the J-MRC functions as a conventional radiative cooling material to supply sub-ambient surface cooling, while the bottom side with low mid-infrared emissivity transfers limited heat via thermal radiation to the low-temperature enclosures. Our experiments validate that the J-MRC possesses an enhanced space cooling performance in comparison to the conventional radiative cooling film. This work provides a valuable design concept for radiative cooling materials, thereby expanding their practical scenarios and contributing to reduce the carbon emission.

Thermal-dependent morphological evolution effect on ion transportation in polyethylene oxide films

PEO films were prepared on glass substrates from dissolved PEO powder in methanol using the solution casting technique. The investigation of these PEO films involved the utilization of Atomic Force Microscopy, Dielectric Relaxation, and Nuclear Magnetic Resonance techniques to explore alterations in the morphology of the polyethylene oxide polymer films as a response to consecutive thermal cycling at various heating and cooling rates. The dielectric loss curve dependency on frequency for each temperature point within the thermal cycles was fitted with a Havriliak–Negami function with an electrical conductivity contribution. The relaxation times associated with the α- and β-relaxation processes were determined by applying the Arrhenius temperature law, enabling the calculation of the respective activation energies. The study reveals the influence of heating rates on the reversibility of dielectric permittivity, dielectric loss, and dielectric strength, which remains consistent at 2 K/min but not at 0.35 K/min. It also emphasizes the impact of crystallinity on the electrical conductivity of PEO films, highlighting the significance of the amorphous state. The investigation of activation energies for β-relaxation and α-relaxation reveals values of 0.40 eV and 0.74 eV, respectively, in line with similar materials. 1H NMR spectra were studied to differentiate between the crystalline and amorphous phases. The peaks corresponding to the crystalline phase exhibit broad NMR signals with overlapping characteristics attributed to the diverse crystalline structural environments that are present.

Characterization and charge transport properties of sodium ion conducting PEO:NaBr solid polymer electrolyte films

AbstractThe study examines the effects of metal salt doping on polyethylene oxide (PEO) solid polymer electrolyte films. Sodium Bromide (NaBr) doped PEO films are prepared using a solution casting technique. The study finds that Na+ rom NaBr interacts with PEO's ether group (C–O–C) through complexation, as confirmed by Fourier Transform Infrared (FTIR) Spectroscopy. X‐ray diffraction analysis reveals that NaBr reduces PEO's degree of crystallinity. The addition of NaBr improves PEO's thermal stability, as shown by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) images show smooth surface morphology of the polymer electrolyte films. The study also finds that the polymer electrolytes are non‐Debye in nature, based on dielectric studies. The highest ionic conductivity of 1.01 × 10−5 S/cm is observed for the 12.5 wt% NaBr doped PEO, with a low activation energy of 0.246 eV. Wagner's polarization technique is used to determine the charge carrier transport numbers, and the transient ionic current technique confirmed the presence of a single ionic species in the polymer electrolyte. Overall, the study suggests that 12.5 wt% NaBr doped PEO films have appropriate electrical properties for developing charge storage devices.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Dielectric relaxation, optical and structural characterizations of complex composite films based on polyethylene oxide doped by low concentration of iodine

The dielectric relaxation, optical, chemical and structural characterizations of synthesized complex composite films based on polyethylene oxide (PEO) doped with low concentrations of iodine (I2) were investigated. XRD results show that all PEO films have a semi-crystalline nature. Increasing I2 concentrations up to 1.0% into PEO films decreases the crystallinity degree from 40.0% to 21.1%. In addition, the bandgap energy decreases from 4.42 to 3.68 eV, as I2 increases to 1.0%. The permittivity and conductivity relaxation processes are studied over the temperatures from 288 K up to 318 K using Havriliak–Negami relationship to investigate the relaxation times, dielectric strengths, and the electrical conductivities. The ionic concentrations dominate the relaxation time due to the favorable I−3-polymer clustering. The findings investigate the impact of I2 and its ions on the segmental dynamics of PEO chains and optical, optoelectronic, and dielectric properties of polymers complexation with the non-metallic element in native form.

Humidity Detection Based on Chitosan/PEO Film Sensor

PEO (Polyethylene Oxide) addition in chitosan has been successfully fabricated as a humidity sensor. In this study, 3% w/v chitosan solution was added by 0.1, 0.2, 0.3, 0.4 and 0.5 (%w/v) of PEO respectively. The sensing properties of chitosan and chitosan/PEO films as humidity sensors have been characterized using Air Handling Unit Trainer, model KT-2000AHU to determine response, repeatability, and recovery toward relative humidity (20-90% RH). The results show that the chitosan/PEO films have a good response when exposed to 90 %RH at room temperature. Those are 288,09 mV obtained by pure chitosan film; 338.97, 384.44, 406.81, 359.69, and 345.84 mV for 0.1, 0.2, 0.3, 0.4, and 0.5% of PEO films respectively that show higher electrical response. The smooth and porous film morphology and chemical interaction between chitosan and PEO through hydrogen bond obtained by SEM and FTIR could be responsible for the higher electrical response. Furthermore, humidity sensing material based on chitosan/PEO films shows good recovery and repeatability.

THE EFFECT OF ADDITION 0.1% IODINE BY WEIGHT ON THE THERMAL PROPERTIES OF POLYETHYLENE OXIDE FILMS

This paper aimed to investigate the thermal properties of thin films of polyethylene oxide (PEO) dispersed with a fixed amount of 0.1 wt.% iodine dopants. The thermal conductivity and resistivity of pure thin PEO films and the prepared ones doped with 0.1 wt.% iodine composites have been studied at different temperatures. The thermal conductivity of these films increases with the increase in temperature and with the ones doped with 0.1 wt.% iodine.

THE EFFECT OF 0.1 WT% IODINE ADDITION ON THE OPTICAL PROPERTIES OF POLYETHYLENE OXIDE FILMS

The study aimed to investigate the optical properties of thin films made of polyethylene oxide dispersed with dopants of a fixed amount of iodine (0.1 wt %). The films prepared by the casting method were optically investigated as a function of the iodine fillers. The study used a UV-visible spectrophotometer technique with a wavelength ranging from (200 to 800) nm and determined the absorption coefficient, refractive index, energy gap, extinction coefficient, optical conductivity, and dielectric constant in the UV-visible wavelength range. The results showed a noticeable change in these optical values with polyethylene oxide doped with 0.1 wt% iodine composites compared with the pure polyethylene oxide films. These measured values of polyethylene oxide doped with 0.1 wt% iodine depend on the wavelength of the incident ultraviolet light.

EFFECTS OF 0.1 WT.% IODINE ADDITIVE ON DIELECTRIC BEHAVIOR AND AC ELECTRICAL CONDUCTIVITY OF POLYETHYLENE OXIDE FILMS

This paper aimed to investigate the electrical characteristics of thin films formed of polyethylene oxide (PEO) distributed with dopants containing a fixed quantity of iodine (0.1 wt.%). The alternating current (AC) electrical properties were studied using the AC impedance technique in the frequency range 3kHz–5MHz and temperature range 30–55oC. The electrically prepared films were made using the casting procedure. This paper compared the variation of AC electrical conductivity with frequency for PEO doped with an iodine-doped polyethylene oxide film and determined some physical quantities and parameters such as AC conductivity, impedance, dielectric constant, and phase angle. The impedance (Z), dielectric constant (e'), dielectric loss (e"), and AC conductivity data observed revealed frequency and temperature. According to polarization processes, the dielectric constant and dielectric loss of the produced thin films increase with doped iodine complexes and decrease with frequency. Iodine, temperature, and frequency all improve AC conductivity.

Studies on structural and electrical properties of NaI doped PEO/CMC blend solid polymer electrolyte

Solid polymer blend electrolyte (SPE) films of Polyethylene oxide(PEO)/Carboxymethyl cellulose (NaCMC) doped with Sodium iodide (NaI), were prepared by solution cast method and their structural, optical and electrical properties were investigated using X-Ray diffraction, Fourier transform infrared spectroscopy, UV–Vis spectrophotometer and Electrical impedance analyser respectively. X-Ray diffraction spectra indicate that, deformation occurred in the structure of the blend followed by doping with NaI salt. The variation in intensity and shifting of characteristic bands in FTIR spectra provides the evidence for formation of complex due to the interaction occurred in the blend with the dopant. Optical energy band gap decreases in the blend samples upon doping and is confirmed by UV–Vis spectrophotometer analysis. Increase of dielectric constant and loss upon doping, exhibits usual behaviour of the polymer electrolytes. An increase in AC conductivity is observed upon doping and maximum conductivity of 9.41 × 10−3 Scm−1 is obtained for 10/90 sample doped with 0.03% Sodium iodide and DC conductivity for the same sample at room temperature is 1.05 × 10–2 Scm−1. In addition, I-T studies confirm the conductivity exhibited by the sample as due to ions and I-V studies show electrochemical stability in the range of good working potential. From the results obtained, it can be inferred that, the prepared sample can be used as polymer electrolytes in the manufacturing of energy storage devices.

HR MAS NMR, dielectric impedance and XRD characterization of polyethylene oxide films for structural phase transitions

The amorphous/crystalline phase transition behavior of PEO films prepared by spin casting method was studied. According to X-ray diffraction (DELTA) analysis, PEO film has a semicrystalline nature at room temperature. The amorphous to crystalline nature of PEO increases with temperature until reaching an amorphous state at 333 K. 1H NMR spectra of PEO in the temperatures between 298 K and 323 K exhibit two main peaks at around 1.132 ppm and 3.174 ppm with very different widths, where the narrow component can be assigned to the mobile polymer chains in the amorphous phase, whereas the broad component is assigned to the more rigid molecules in the crystalline phase. The calculated activation energies from the Arrhenius fit of the Γ1 data of the crystalline and amorphous phases are comparable and found to be 0.252 eV and 0.221 eV, respectively. Form fitting dielectric loss (ε″) and the electrical modulus (M″) data with the Havriliak-Negami model with addition of the electrical conductivity term in the case of ε″, it was deduced that the inverse relaxation time (τ−1), dielectric strength (Δε) and electrical conductivity (σ) follow an Arrhenius-like behavior plot versus reciprocal temperature.

PEO-PDMS-based triboelectric nanogenerators as self-powered sensors for driver status monitoring

The number of traffic accidents is growing with the ever-increasing vehicles, and most of the traffic accidents are due to fatigue or distracted driving. Thus, it is necessary to monitor the driver’s status in real-time. However, current detection methods mainly rely on sensors that need a continuous power supply. Here, a polyethylene oxide (PEO)-polydimethylsiloxane (PDMS)-based triboelectric nanogenerator as a self-powered sensor was designed for biological signal monitoring. According to the experimental results, by adding green and low-cost substances sodium chloride and tea powder in PEO and PDMS films, respectively, the output voltage and current of the sensor are increased by about 9.75 and 8.21 times. The proposed sensor has a high sensitivity of 0.7 V/kPa in the linear range of 0–50 kPa and a fast response time of 36 ms. Moreover, a high-performance and low-cost driver status monitoring system was designed. The sensors were attached to the driver's neck and seat belt to monitor neck activities and breathing states. By extracting parameters from the output voltage waveform, the system can judge and display the degrees of driver fatigue and concentration. The proposed system is conducive to improving road traffic safety and has the potential to be applied in intelligent transportation.

Correlation of electrical, thermal, and crystal parameters of complex composite films based on polyethylene oxide (PEO) doped by copper sulfate (CuSO4)

Ionic conductivity and the conductivity mapping of PEO/CuSO4 complex composite films are investigated to show the effect of the complexation of the Cu+2 and SO4−2 ions on the PEO matrix. Adding CuSO4 into the PEO matrix decreases the crystallinity degree of PEO films and consequently enhances the ionic conductivity and charge diffusion due to increasing the segmental motion of PEO. The FTIR spectra demonstrate the complexation of the Cu+2 ions to the ether oxygen in PEO films, while the SO4−2 ions behave as free ions in the polymer matrix as elucidated in the vibrational modes of PEO/CuSO4 thin films. Introducing CuSO4 into the PEO matrix improves the thermal stability of the complex composite films. Moreover, the conductivity of the pure PEO film is 1.67 × 10−4 S/cm at room temperature. Increasing CuSO4 concentration in the PEO films to 20% increases the ionic conductivity up to 6.13 × 10−4 S/cm.

Re-Stickable Yarn Supercapacitors with Vaper Phase Polymerized Multi-Layered Polypyrrole Electrodes for Smart Garments.

Yarn supercapacitors have attracted significant attention for wearable energy storage due to their ability to be directly integrated with garments. Conducting polymer polypyrrole (PPy) based yarn supercapacitors show limited cycling stability because of the huge volume changes during the charge-discharge processes. In addition, laundering may cause damage to such yarn supercapacitors. Here, the fabrication of PPy-based re-stickable yarn supercapacitors is reported with good cycling stability by employing vapor phase polymerization (VPP) and water-soluble polyethylene oxide (PEO) film as the adhesive layer. VPP duration and cycle are controlled to achieve multi-layered PPy electrodes. The assembled yarn supercapacitors show a good cycling stability with capacitance retention of 79.1% after 5000 charge-discharge cycles. The energy stored in the yarn supercapacitor is sufficient to power a photodetector. After gluing the yarn supercapacitors onto a PEO film, the devices can be stunk on and peeled off the garment to avoid the mechanical stresses during the washing process. Three yarn supercapacitors connected in parallel on PEO film show negative changes in electrochemical performance after 5 sticking-peeling cycles. This work provides a facile way to fabricate PPy-based re-stickable energy storage devices with high cycling stability for smart garments.

Plasticizing effect on polyethylene oxide doped ammonium perchlorate

Plasticized polymer complex films of polyethylene oxide with ammonium perchlorate (NH4ClO4) are synthesized by using solution cast technique. Propylene carbonate (PC) used as dopant to enhance conductivity of polymer electrolyte. The prepared films are characterized in detail using X-ray diffraction, infrared spectral analysis, transient ionic current, and electrochemical impedance studies. Plasticized polymer electrolyte shows high ionic conductivity (∼10−4 S/cm) which appear as novel electrolyte for electrochemical devices.

A Ring-Shaped Hand Motion Sensor Based on Triboelectricity

Gesture recognition is one of the most important functions of human-computer interaction (HCI). In this regard, a self-powered finger ring hand motion sensor was proposed in the present study. To this end, a single sensing unit consisting of a Polydimethylsiloxane (PDMS) film, a polyethylene oxide (PEO) film and a spacer was constructed. Then the finger bending and stress were monitored through numerous sensing units. In order to increase the contact area, ordinary textile stripes were used on the PDMS film surface. Then finite element simulations were carried out to evaluate the performance of the proposed sensor under different conditions. The obtained results show that the sensor has promising charge transfer features. Moreover, it was found that the sensitivity of the sensing unit in the range of 0–7 N is 94.48 mV/N. Then the ring finger hand motion sensor was set on a single finger to simulate a mouse and distinguish click, double-click and click time. Accordingly, it was demonstrated that numbers, letters and phrases in the ASL sign language can be accurately identified even in similar cases with small differences.

Stretchable gas barrier films achieved by hydrogen‐bond self‐assembly of nano‐brick multilayers

AbstractInorganic–organic hybrid films containing two‐dimensional nanosheets have shown good gas barrier performance, but moderate tensile property, because of the rigid characteristics of covalent or ionic bonds between the assembly units. In this work, we used LDH nanosheets rich in hydroxyl groups as building units, followed by modification of tannic acid (TA), to assemble with polyethylene oxide (PEO) through hydrogen bonds. Compared with previous work, the tensile property and oxygen barrier performance of (TA@LDH/PEO)n films have been significantly improved. A 50‐bilayer TA@LDH/PEO film, deposited on a 1 mm thick natural rubber substrate, results in a 29× reduction (contrast with bare substrate) in oxygen transmission rate and maintains its good barrier property even under a large elongation of 120%. The excellent tensile and gas barrier properties are attributed to the ductility of hydrogen bond network among building blocks and the significant prolongation of oxygen transmission path induced by LDH nanosheets.

Combining Hyperbranched and Linear Structures in Solid Polymer Electrolytes to Enhance Mechanical Properties and Room-Temperature Ion Transport

Polyethylene oxide (PEO)-based polymers are commonly studied for use as a solid polymer electrolyte for rechargeable Li-ion batteries; however, simultaneously achieving sufficient mechanical integrity and ionic conductivity has been a challenge. To address this problem, a customized polymer architecture is demonstrated wherein PEO bottle-brush arms are hyperbranched into a star architecture and then functionalized with end-grafted, linear PEO chains. The hierarchical architecture is designed to minimize crystallinity and therefore enhance ion transport via hyperbranching, while simultaneously addressing the need for mechanical integrity via the grafting of long, PEO chains (M n = 10,000). The polymers are doped with lithium bis(trifluoromethane) sulfonimide (LiTFSI), creating hierarchically hyperbranched (HB) solid polymer electrolytes. Compared to electrolytes prepared with linear PEO of equivalent molecular weight, the HB PEO electrolytes increase the room temperature ionic conductivity from ∼2.5 × 10–6 to 2.5 × 10−5 S/cm. The conductivity increases by an additional 50% by increasing the block length of the linear PEO in the bottle brush arms from M n = 1,000 to 2,000. The mechanical properties are improved by end-grafting linear PEO (M n = 10,000) onto the terminal groups of the HB PEO bottle-brush. Specifically, the Young’s modulus increases by two orders of magnitude to a level comparable to commercial PEO films, while only reducing the conductivity by 50% below the HB electrolyte without grafted PEO. This study addresses the trade-off between ion conductivity and mechanical properties, and shows that while significant improvements can be made to the mechanical properties with hierarchical grafting of long, linear chains, only modest gains are made in the room temperature conductivity.