Ion transport mechanisms in oxymethylene linked poly(ethylene oxide)-poly(N,N-dimethyl-acrylamide)-LiClO4 composite polymeric electrolytes have been studied. It has been found that the addition of poly(N,N-dimethyl-acrylamide) fillers increases ambient and sub-ambient temperature conductivities by about 1-2 orders of magnitude in comparison with the pristine oxymethylene linked poly(ethylene oxide)-LiClO4 electrolyte. DSC and FTIR investigations demonstrate strong interactions between the poly(N,N-dimethyl-acrylamide) filler added and LiClO4 leading to the formation of different molecular complexes. The presence of a highly flexible amorphous polyether phase evident from DSC measurements seems to be responsible for the conductivity enhancement.