The syntheses of ten novel mono-, di- or tri-cationic poly(ethylene glycol)-based ionic liquids (IL_PEGs), incorporating tetra-substituted ammonium cations, are described. The poly(ethylene glycol) chains could be bridged or not and bore the cation. In the di-cationic IL_PEG family, hydrophobic poly(methylene) or amphipathic poly(oxyethylene) spacers, with various lengths, were designed to connect the polar heads, while in the tri-cationic IL_PEG family, the spacer was constituted by substituted diamines. The thermophysical properties such as viscosity or thermal stability were also investigated.