In recent years increasing attention is devoted to the development of conductive nanofiller (generally single-wall carbon nanotubes, multi-wall carbon nanotubes (MWCNTs) and graphene) containing thermoplastic and thermosetting polymer nanocomposites for broad range applications in electrotechnics, electronics, energetics, transport, structural engineering, medicine and elsewhere. At the development of these multiphase systems especial attention is devoted to the improvement of interfacial interaction between the carbonaceous nanofiller and polymer matrix. This is an important prerequisite for development of high-performance materials for the above mentioned application areas. Consequently this research is devoted to functionalization of MWCNTs with surface active imidazolium ionic liquid (IL) incorporating hexadecyl moieties for enhancing the dispersion of the nanofiller in the of polyethylene (PE) matrix. ILs with different hydrocarbon chain lengths have been used. Initially IL-MWCNT-PE masterbatches have been obtained by using solvent based approach. Consequently masterbatches have been melt compounded with PE matrix ensuring that the nanofiller concentration ranges from 0 to 10 wt.%. Rheological, mechanical, dielectric and thermal properties of the developed PE composites have been investigated by using rotational viscometry, stress-strain analysis, dynamic mechanical thermal analysis, broadband dielectric spectroscopy, differential scanning calorimetry, thermogravimetric analysis and laser flash analysis.