Tri block-copolymer poly(iminoethylene)-b-poly(oxyethylene)-b-poly(iminoethylene) with a poly(oxyethylene) central block (PEI-b-PEO-b-PEI) were used as a "dual" matrix for polymer electrolytes having selectivity for hard cations (Li+/PEO) in one phase and for soft cations (Cu2+/PEI) in the other. Conductivity measurements were recorded for 20:1, 12:1 and 8:1 coordinating atom (O or/and N) to cation (Li+, Cu2+) ratios, for each of the three complexes studied: PEI-b-PEO-LiTFSI-b-PEI, PEI-Cu(TFSI)(2)-b-PEO-b-PEI-Cu(TFSI)(2) and PEI-Cu(TFSI)(2)-b-PEO-LiTFSI-bPEI-Cu(TFSI)(2). For either low (20 degrees C) or high temperature (80 degrees C) the highest conductivity was given by the polymer electrolyte based on Cu (TFSI)2 with N/Cu2+ =20:1 (10(-6), respectively 2 x 10(-4) S cm(-1)). In the present paper, the conductivity evolution is discussed in relation with the polymer structure, the type and the concentration of the salt and the thermal behavior of our systems. (c) 2006 Elsevier B.V All rights reserved.