Structure and Properties of Electroactive Composites Based on Oligomers of Different Molecular Weight Doped with Lithium Perchlorate Salt

Authors L.K. Matkovska1, V.L. Demchenko1, V.I. Shtompel1, О.K. Matkovska2

1Institute of Macromolecular Chemistry of the NAS of Ukraine, 48, Kharkivske Chaussee, 02160 Kyiv, Ukraine

2PHEE “Kyiv Medical University”, 2, Boryspilska St., 02099 Kyiv, Ukraine

Issue Volume 14, Year 2022, Number 4
Dates Received 01 June 2022; revised manuscript received 15 August 2022; published online 25 August 2022
Citation L.K. Matkovska, V.L. Demchenko, et al., J. Nano- Electron. Phys. 14 No 4, 04008 (2022)
PACS Number(s) 82.35. – x
Keywords Epoxy oligomer, Poly(ethylene glycol), Lithium salt, Structure (104) , Properties (87) .

Polymer mixtures are an important object of scientific and industrial interest and doping with salts is a common way to implement composite conductivity. The structure and properties of composites based on oligomers of different molecular weight, namely amorphous diglycidyl ether of poly(ethylene glycol) (DEG-1, Mw  372 g/mol) and highly crystalline poly(ethylene glycol) (PEG, Mw  10,000 g/mol), and Li+ ions have been investigated. Polymeric organic-inorganic systems have been investigated by differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and broadband dielectric spectroscopy. Using DSC and WAXS methods, it has been shown that composites with PEG have an amorphous-crystalline structure. The average crystallite size is 4.0 nm according to the study of WAXS. The DSC method revealed a decrease in the degree of PEG crystallinity in the composite due to the plasticizing ability of DEG-1 and the interaction of PEG with lithium perchlorate salt. Using the SAXS method, it has been established that there are regions of heterogeneity with a size of 95-130 nm in the volume of the studied composites. Studies of the electrical characteristics of polymer systems have shown that the doping of the composite with a lithium salt leads to an increase in the conductivity of the samples by two orders of magnitude. The temperature dependences of the conductivity at direct current for the studied composites do not obey the Arrhenius dependence and are analyzed using the Vogel-Tamman-Fulcher equation. The studied composites can be attributed to fragile.

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