The copolymer of acrylonitrile (AN), methyl methacrylate (MMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) is synthesized in 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF(4)). The dynamic mechanical properties of the resulting gel polymer electrolytes containing ionic liquid are measured. Results show that the gel polymer electrolytes possess two glass transitions in the temperature range from -80 degrees C to 120 degrees C. Moreover, the storage modulus, loss modulus and the height of tan delta peaks are found to depend on frequency, nature of lithium salt, content of lithium salt and ionic liquid. It is also shown that the activation energy varies with the content of lithium salt and ionic liquid. (C) 2008 Elsevier B.V. All rights reserved.