We characterize the DC conductivity (sigma(0)) of solution electrolytes prepared by adding LiCF3SO3 (LiTf) salt to a (50150 w/w) solution of branched poly(ethyleneimine) (PET) in N,N-dimethylformamide (DMF). The value of sigma(0) increases with decreasing LiTf concentration over the range of compositions studied due to the formation of contact ion pairs at higher LiTf concentrations, with the highest value of sigma(0) exceeding, 10(-3) S cm(-1) at 20 degrees C. Rubber-like gel electrolytes are prepared by epoxide-amine crosslinking of selected solutions by addition of cliglycidyl ether of bisphenol A (DGEBA). Holding the [N]:[Li] mote ratio fixed, increasing the crosslink density dramatically decreases sigma(0) at all temperatures studied. The decrease in sigma(0) cannot be attributed to an increase in the glass transition temperature, as little variation in T, is noted amongst the samples clue to their high solvent content. Rather, we propose that the decrease in conductivity is due to loss of fast segmental motions associated with chain ends, which become tethered to the network upon crosslinking. (C) 2007 Elsevier Ltd. All rights reserved.