Ionic conductivity of PVdF-co-HFP/LiClO<sub>4</sub>in terms of free volume defects probed by positron annihilation lifetime spectroscopy

Yahşi, Uğur; Deligöz, Hüseyin; Tav, Cumali; Deǧer, D.; Yılmaztürk, Serpil; Erdemci, Gonca; Coşkun, Bilgehan; Yılmazoğlu, Mesut; Yakut, Şahin

doi:10.1080/10420150.2018.1552959

Cited by 13 publications

(7 citation statements)

References 58 publications

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“…Therefore, the increase in τ 3 or V h is assigned the thermal expansion of free volume. The behavior of τ 3 or V h with temperature is in accordance with other polymers . In the low‐temperature region, T < 130°C, the increase of V h is dominated by molecular vibrations and local motions.…”

Section: Resultssupporting

confidence: 84%

“…The behavior of τ 3 or V h with temperature is in accordance with other polymers. 33,54 In the low-temperature region, T < 130 C, the increase of V h is dominated by molecular vibrations and local motions. At the onset temperature (130.54 ± 0.82), V h changes its slope and it is assigned the glass transition temperature T g of the Na-CMC/PAM blend.…”

Section: Pals Measurementsmentioning

confidence: 99%

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Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Awad

El‐Gamal

Sayed

et al. 2019

Polymers for Advanced Techs

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Polyblend and nanocomposite films of sodium salt of carboxymethylcellulose (Na‐CMC)/polyacrylamide (PAM) and Na‐CMC/PAM modified with carbon nanotubes (CNT) were synthesized by the solution casting technique. The effect of PAM and CNT loading on the structural, optical, and nanoscale free volume properties of Na‐CMC was studied. X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy exhibited the existence of strong interactions between Na‐CMC and PAM and the non‐destructive effect of CNT on Na‐CMC/PAM structure. The HR‐TEM revealed the multi‐walled structure of CNT with a 7.06‐nm wall thickness and a 6.92‐nm wall inner diameter. Positron annihilation lifetime spectroscopy (PALS) was done, in a vacuum and at 30°C to 200°C, to investigate the nanoscale free volume properties by using a conventional fast‐fast coincidence spectrometer. It was found that the o‐Ps lifetime (τ3) and free volume (Vh) increase with increasing CNT percentage in the Na‐CMC/PAM blend. The distribution of the o‐Ps lifetime was broadened with increasing CNT ratios. Furthermore, the glass transition temperature (Tg) increases with increasing loads of CNT. For the first time, a correlation was done between Urbach energy (EU) and Vh. Finally, the results were represented and discussed in the frame of free volume properties. Optical measurements showed that the transmittance T% of Na‐CMC/PAM was 91.12% and decreased to 68.42% and 36.45% after loading with 1.0 and 2.0 wt % CNT. In addition, the blend shows higher insulating properties compared with the individual polymers. The CNT incorporation reduces the band gap significantly and increases the EU in the films.

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Section: Resultssupporting

confidence: 84%

Section: Pals Measurementsmentioning

confidence: 99%

Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Awad

El‐Gamal

Sayed

et al. 2019

Polymers for Advanced Techs

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“…Yahsi et al [56] used positron annihilation lifetime spectroscopy and Simha-Somcynsky hole theory to study the effect of the lithium salt content and temperature on the free volume size and fraction. It is disclosed that the free volume (or ortho-positronium lifetime) increases linearly with the temperature, and the free volume fraction also changes with the lithium salt content (Figs.…”

Section: Free Volume Modelmentioning

confidence: 99%

Solid polymer electrolytes: Ion conduction mechanisms and enhancement strategies

Zhang

Meng

Hou

et al. 2023

Nano Research Energy

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Solid polymer electrolytes (SPEs) possess comprehensive advantages such as high flexibility, low interfacial resistance with the electrodes, excellent film-forming ability, and low price, however, their applications in solid-state batteries are mainly hindered by the insufficient ionic conductivity especially below the melting temperatures, etc. To improve the ion conduction capability and other properties, a variety of modification strategies have been exploited. In this review article, we scrutinize the structure characteristics and the ion transfer behaviors of the SPEs (and their composites) and then disclose the ion conduction mechanisms. The ion transport involves the ion hopping and the polymer segmental motion, and the improvement in the ionic conductivity is mainly attributed to the increase of the concentration and mobility of the charge carriers and the construction of fast-ion pathways. Furthermore, the recent advances on the modification strategies of the SPEs to enhance the ion conduction from copolymer structure design to lithium salt exploitation, additive engineering, and electrolyte micromorphology adjustion are summarized. This article intends to give a comprehensive, systemic, and profound understanding of the ion conduction and enhancement mechanisms of the SPEs for their viable applications in solid-state batteries with high safety and energy density.

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“…Positron annihilation lifetime spectroscopy (PALS) was executed using a fast-fast coincidence system evaluating the time interval between the prompt γ-ray of 1274 keV as the start signal and the annihilation γ-ray of 511 keV as the stop signal. The positron source was prepared by placing a solution of about 30 µCi of 22 NaCl on a thin aluminum foil (5 µm thick) inserted between two pieces of film samples with a thickness of 2 mm or more.…”

Section: Positron Annihilation Spectroscopy Analysismentioning

confidence: 99%

“…Open spaces called "free volume" exist in the polymer structure as the chemical form changes. The free volume model of a polymer can explain several critical physical phenomena such as viscosity [14][15][16][17][18][19][20][21], ionic conductivity [22,23], relaxation [24], glass transition temperature, and other mechanical and thermodynamic properties. Several techniques such as X-ray or neutron scattering, differential scanning calorimetry, electron microscopy, dynamic mechanical study, and Fourier transform infrared spectroscopy can be utilized to measure the free volume of a polymer and to indirectly provide knowledge of the free volume of polymers and their composites [25].…”

Section: Introductionmentioning

confidence: 99%

Effect of Free Volume on Curcumin Release from Various Polymer-Based Composite Films Analyzed Using Positron Annihilation Lifetime Spectroscopy

et al. 2021

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This work reports the effects of free volume on curcumin release in various polymer-based composite films. Curcumin-reinforced biocomposite films were fabricated with natural biopolymers (carrageenan and chitosan) and bioplastics (poly(lactide) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT)) via the solvent casting method. The curcumin release test was performed using an aqueous medium, and it was found that it was released the fastest in the carrageenan film, followed by the chitosan, PLA, and PBAT films, presumably owing to the dissimilarity of the polymer matrix. The free volume of the polymer films was determined using positron annihilation lifetime spectroscopy (PALS) to understand the release phenomena of curcumin. The free volume fraction was varied and reliant on the type of polymer, with the highest in the PBAT-based film followed by the PLA-, chitosan-, and carrageenan-based films. The free volume method helps analyze the release of bioactive compounds in a polymer matrix and may help to achieve a better understanding of the release of bioactive compounds.

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Ionic conductivity of PVdF-co-HFP/LiClO₄in terms of free volume defects probed by positron annihilation lifetime spectroscopy

Cited by 13 publications

References 58 publications

Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Solid polymer electrolytes: Ion conduction mechanisms and enhancement strategies

Effect of Free Volume on Curcumin Release from Various Polymer-Based Composite Films Analyzed Using Positron Annihilation Lifetime Spectroscopy

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Ionic conductivity of PVdF-co-HFP/LiClO4in terms of free volume defects probed by positron annihilation lifetime spectroscopy

Cited by 13 publications

References 58 publications

Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Characterization, optical, and nanoscale free volume properties of Na‐CMC/PAM/CNT nanocomposites

Solid polymer electrolytes: Ion conduction mechanisms and enhancement strategies

Effect of Free Volume on Curcumin Release from Various Polymer-Based Composite Films Analyzed Using Positron Annihilation Lifetime Spectroscopy

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Product

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Ionic conductivity of PVdF-co-HFP/LiClO₄in terms of free volume defects probed by positron annihilation lifetime spectroscopy