Miscibility and Conductivities of PEO/PMMA-LiClO&lt;sub&gt;4&lt;/sub&gt; Solid Polymer Electrolyte

et al. 2015

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Summary: In this study, thermal properties and ion-polymer interactions of lithium perchlorate (LiClO 4 ) in poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blend prepared by solution casting technique were elucidated. The spectroscopic studies of the salt-free and salt-doped PEO/PMMA blends were investigated using x-ray diffraction (XRD) and Fourier transform infra-red (FTIR), respectively. XRD study reveals that the crystalline structure of PEO is slight change when PMMA is blended to PEO. The thermal behaviour of PEO, PMMA and their blends with and without LiClO 4 was investigated by differential scanning calorimetry (DSC). The presence of a single and composition dependent glass transition temperature (T g ) reflects the miscibility of the salt-free PEO/PMMA blends in the molten state. The T g s of PEO, PMMA and the blends generally increase with ascending mass fraction of salt (W S ). However, PEO/PMMA 50/50 blend with W S ! 0.091 shows phase separation between the two polymers. The melting temperature (T m ) and crystallinity (X Ã ) of PEO are suppressed when blended with PMMA, thus, confirm the miscibility of the salt-free PEO/PMMA blends in the molten state. Presence of LiClO 4 to PEO, PMMA and their blends does not influences the X Ã of PEO. Investigation by FTIR does not show any specific interaction between PEO and PMMA for the salt-free blends whereas for the salt-doped blends, Li þ ions are observed to coordinate with the oxygen atom of both the PEO ether and the PMMA carboxyl groups. Impedance spectroscopy study demonstrates that the LiClO 4 -doped PEO/PMMA 75/25 blend has lower ion conductivity than that of the PEO þ LiClO 4 system but recorded enhanced conductivity as compared to PMMA þ LiClO 4 systems at W S ¼ 0.091.

Section: Resultsmentioning

confidence: 99%

Section: à4mentioning

confidence: 99%

Section: à4mentioning

confidence: 99%

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confidence: 99%

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On Thermal and Spectroscopic Studies of Poly(ethylene oxide)/Poly(methyl methacrylate) Blends with Lithium Perchlorate

Karim

Sim

et al. 2015

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“…This is due to the high crystallinity (up to 70%) for high molar‐mass SPEs . Thus, various approaches have been made to enhance to conductivity of SPEs such as addition of plasticizers and fillers, polymer blending, polymer hosts using copolymers etc. Blending PEO with another component is one of the cost‐effective and convenient ways for the enhancement of the conductivity of SPEs by compositional change of the blends.…”

Section: Introductionmentioning

confidence: 99%

Thermal Properties and Morphology of Poly(ethylene oxide)/Poly(n‐butyl methacrylate) Blends

Ramli

Ali

2018

From the thermodynamic point of view, most of the high molar‐mass binary polymer blends are immiscible due to the entropic contribution to the free energy of mixing is relatively small. The miscibility of the systems on the molecular scale can be assessed by the thermal properties such as quantities of glass transition temperature (Tg) and change in heat capacity (ΔCp) of the polymers. For a semi‐crystalline polymer such as poly(ethylene oxide) (PEO), the crystallinity (X*) and the melting temperature (Tm) can also give some hints on the miscibility. Apart from the thermal properties, additional scientific findings such as morphology of the blends are needed as supplementary evidences to support the results. We focus on the PEO as the polymer host, blends with poly(n‐butyl methacrylate) (PnBMA) which were prepared using solution casting technique. Thermal properties of PEO/PnBMA polymer blends were investigated by modulated differential scanning calorimeter (MDSC) on the isothermal crystallized samples at 25 °C. Tg of PEO in the blends do not show significant variation with addition of PnBMA for entire composition range while for Tg of PnBMA in the blends, it is challenging to be estimated under the experimental condition due to the overlapping of the Tg of PnBMA and melting endotherm of PEO. Constancy of quantity Tg of PEO and ΔCp of PEO corresponding to the content of PEO in the blends suggest that PEO and PnBMA are immiscible for entire blend composition. X* and Tm of PEO in the blends show insignificant variation in PEO/PnBMA blends, when PEO as major component. This implies that these blends are immiscible under the experimental conditions as agreed with results of Tg and ΔCp. Spherulitic morphologies of PEO in the blends were studied by polarized optical microscopy (POM). PnBMA phase disperses randomly in PEO matrix when PEO in excess. The absence of significant change for the fibrillar spherulitic structures of PEO spherulites with addition of PnBMA (when PEO is the major component) suggests that immiscibility of PEO and PnBMA. Besides, the crystalline structure of PEO in PEO/PnBMA blends using X‐ray diffraction (XRD) reveals that the crystalline structure of PEO is not disturbed with the addition of PnBMA when PEO is in excess as the two distinct peaks of PEO do not shift as compared to neat PEO. Impedance spectroscopy (IS) studies show that the ionic conductivities (σDC) of the polymer blends at room temperature slightly increase with increasing of PEO with the order of magnitude of 10−11–10−10 S cm−1. This system serves as a potential polymer host as solid polymer electrolytes when added with inorganic salt.

Thermal, Conductivity and Molecular Interaction Studies of Poly(ethylene oxide)/Poly(methyl acrylate) Solid Polymer Electrolytes

Halim

Winie

2017

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Summary Solid polymer electrolytes of poly(ethylene oxide) (PEO) and poly(methyl acrylate) (PMA) with addition of lithium perchlorate (LiClO4) were studied. Samples were prepared by solution casting method. An existence of single and compositional‐dependant glass transition temperature (Tg) of PEO/PMA systems [studied by Differential scanning calorimetry (DSC)] shows miscibility of the binary PEO/PMA blends as well as when added with small of amount of LiClO4 in the molten state and amorphous phase. The systems are miscible in molten state and amorphous phase at high salt content with PEO content in the blends is in excess. In this case, the Tgs of the PEO/PMA blends increase slightly with increasing salt concentration suggesting the molecular interaction of salt with the polymers. Impedance spectroscopy (IS) studies reveal that PEO/PMA 80/20 blend (w/w) added with 0.12 of LiClO4 (YS) shows the highest conductivity (σDC = 1.43 × 10−5 S cm−1) as compared to PEO/LiClO4 system at the same salt concentration (σDC = 6.43 ×10−6 S cm−1). Results of Tg using DSC and molecular interaction from Fourier‐transform infrared (FTIR) spectra suggest that blend with PEO in excess, Li+ ions coordinate with ether oxygen of PEO instead of carbonyl oxygen of PMA. Hence, the percolation pathway for these SPEs is lying in the amorphous region of the PEO phase.