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.

In the Part 2 of this article, we present the phenomenological response of the dielectric relaxation for polymer electrolytes monitored by electrochemical impedance spectroscopy (EIS) in terms of electrochemical point of view, such as impedance (Z*), permittivity (ε*), loss tangent (tan δ), modulus (M*) and conductivity (σ*) spectra. It is noteworthy to note that all the electrochemical aspects mentioned are of interest for conduction and seen as closely related to each other indirectly or directly. Two different systems; solid polymer electrolyte (SPE) [poly(ethylene oxide) (PEO) + lithium perchlorate (LiClO4)] and non-SPE [poly(methyl acrylate) (PMA) + LiClO4] were employed for discussion. EIS is a powerful technique to characterize the electrical properties of polymer electrolytes. The results suggest that impedance and modulus are of interest for decoupling of dielectric and electric properties by evaluating the short-range and long-range mobility of the charged entities, respectively. One is able to identify the conduction mechanism of the polymer electrolytes easily if the responses are well understood. The objective of this article to introduce a simplified yet an insightful background and technique that is easy to be followed and useful for educational purposes especially for beginners or young researchers for both undergraduates and postgraduates.

The studies of phase behavior, dielectric relaxation, and other properties of poly(ethylene oxide) (PEO)/poly(methyl acrylate) (PMA) blends with the addition of lithium perchlorate (LiClO4) were done for different blend compositions. Samples were prepared by a solution casting technique. The binary PEO/PMA blends exhibit a single and compositional-dependent glass transition temperature (Tg), which is also true for ternary mixtures of PEO/PMA/LiClO4 when PEO was in excess with low content of salt. These may indicate miscibility of the constituents for the molten systems and amorphous domains of the systems at room temperature from the macroscopic point of view. Subsequently, the morphology of PEO/PMA blends with or without salt are correlated to the phase behavior of the systems. Phase morphology and molecular interaction of polymer chains by salt ions of the systems may rule the dielectric or electric relaxation at room temperature, which was estimated using electrochemical impedance spectroscopy (EIS). The frequency-dependent impedance spectra are of interest for the elucidation of polarization and relaxation of the charged entities for the systems. Relaxation can be noted only when a sufficient amount of salt is added into the systems.

Summary Polymer blends of poly(ethylene oxide) (PEO) and poly(methyl acrylate) (PMA) were prepared by solution casting method. Thermal stability of the binary PEO/PMA blends was examined by termogravimetric analysis (TGA). Decomposition temperatures of the binary blends were estimated from the onsets of the weight loss curves of TGA thermograms. The decomposition temperatures of the blends increase when the content of PEO elevates. Hence, PEO has a better thermal stability as compared to PMA. The activation energy of thermal decomposition of each sample was calculated from the initial stage of the decomposition. Quantities of EA increase when content of PEO increases in the blends. Differential scanning calorimeter (DSC) was used to investigate the thermal properties of binary PEO/PMA blends. An existence of a single and composition‐dependent glass transition temperature (Tg) for the blends indicates the miscibility of the PEO/PMA blends. The Tgs of PEO/PMA blends increase when PMA content increases. Furthermore, when PMA is blended with PEO, the crystallinity (X*) and melting temperature (Tm) of PEO in PEO/PMA blends are depressed. Thus, the miscibility of the blends in the molten state is in agreement with Tg results. Fourier‐transform infrared (FTIR) spectroscopy was used to study the intermolecular interaction of between PEO and PMA in the blends. The characteristic absorbance bands of ether and carbonyl groups of PEO and PMA were examined by FTIR. PEO and PMA only display weak van der Waals interactions in blends. Hence the miscibility of PEO and PMA in the blends may be more towards the entropic effect instead of the enthalpic effect.

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