Solvent-free polymer electrolyte blends of the amphiphilic polyethoxide (I) and the polytetrahydrofuran copolymer (II) with LiClO4 or LiClO4/LiBF4 mixture have been prepared. [GRAPHICS] In II -A- is either -CH2- (IIC1) or -CH2C(=CH2)CH2-(IID4), dc measurements using Li electrodes on the cells (Li / I/II-Li salt / Li) demonstrate a 'self-tracking' process over ca. 24 h during which time conductivities increase from ca. 10(-6) to 10(-3) S cm(-1) at 25 and 30 degreesC. The de results are supported by ac impedance measurements using indium tin oxide (ITO) electrodes in which the complexes undergo transitions at ca. 90 degreesC to give a conductivity after cooling of 6 x 10(-4) S cm(-1) at 20 degreesC with low temperature dependence. Structural analysis and molecular dynamics modelling indicate that the cations occupy unimpeded helices of I and anions are located in the interhelical spaces. Mechanisms of 'tracking' involving shear-induced orientation of polymer I by polymer II and the redistribution of ions between I and II following imposition of the field are proposed.