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2025 (English)In: Chemistry Switzerland, E-ISSN 2624-8549, Vol. 7, no 6, article id 194Article in journal (Refereed) Published
Abstract [en]
In this work, nickel oxide nanoparticles (NiO NPs) were synthesized sonochemically in the ionic liquid 1,2-(propanediol)-3-methylimidazolium hydrogen sulfate ([PDOHMIM+][HSO4−]) at different loadings (8 wt.%, 15 wt.%, and 30 wt.%), and subsequently coated with polyethylene glycol (PEG). Structural characterization (XRD, FTIR, TEM, TGA) confirmed a cubic NiO spinel phase with an average crystallite size of ~8 nm, which increased to 20–28 nm after PEG coating. Electrical measurements (100 Hz–1 MHz) showed that AC conductivity (σAC) increased with both frequency and NiO content, whereas the dielectric constant (ε′) and loss tangent (tan δ) decreased with frequency. DFT calculations (B3LYP/6–311+G(2d,p)) on the [PDOHMIM+][HSO4−] ion pair showed that there were strong hydrogen bonds, an uneven charge distribution, and stable electrostatic interactions that help keep NiO NPs stable and spread them evenly in the ionic liquid. In general, both experimental and theoretical studies show that PEG-coated [NiO NPs + IL] nanostructures exhibit improved dielectric stability, enhanced interfacial polarization, and tunable electronic properties.
Place, publisher, year, edition, pages
MDPI AG, 2025
Keywords
AC conductivity, dielectric properties, ionic liquid, NiO nanostructures, PEG polymer
National Category
Physical Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-375746 (URN)10.3390/chemistry7060194 (DOI)001648159900001 ()2-s2.0-105026679467 (Scopus ID)
Note
QC 20260122
2026-01-222026-01-222026-01-22Bibliographically approved