A series of new polymer electrolytes based on polydimethylsiloxane bearing 1-N-methylimidazolium-pentyl iodide side chains, (PILs) with different ionic functionality have been synthesized and characterized. In order to decrease the PILs viscosity and improve the ionic transport, ILs and organic solvent were added. The physiochemical and electrochemical properties of these PILs and their blends with ILs i.e. 1-methyl-3-propylimidazolium iodide (MPII) or 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (MPI TFSI), including density, glass transition temperature, viscosity, ionic conductivity, ionicity and diffusion coefficient were determined. Furthermore, the effect of ethylene carbonate (EC) on the physicochemical and electrochemical properties of PILs was also evaluated in terms of ionic conductivity and diffusion coefficient.