Аннотация:A series of bis(trifl uoromethylsulfonyl)imide hydrophobic monocationic ionic liquids(ILs) with alkyl and siloxane substituents in the imidazolium cation were synthesized andtheir physicochemical properties were studied. The eff ect of the substituent nature in theimidazolium cation on the properties of the synthesized ILs was studied. The ILs obtainedare characterized by a working temperature range from –70 to 300 C, viscosity values inthe range of 65—184 cSt (30 C), and surface tension ranging from 23 to 31 mN m–1(20 C), being promising lubricants for modifi cation of hydrophobic solid surfaces.