Li-7 and F-19 NMR linewidths and impedance spectra are reported for low-dimensional CmOn (I):LiBF4 mixtures. Data for the ionophilic polymer C18O5 is compared with that for the ionophobic C18O1 and the block copolymer C16O1O5(21%) (21 mol% of C16O5). In C18O5:LiBF4 (1: 1) narrow Li-7 linewidths, which were observed in the liquid crystal phase above the side chain melting temperature (similar to 50 degrees C), persist in the crystal down to ca. 0 degrees C and broaden below -20 degrees C. However, in C18O1:LiBF4 (1:0.6) narrow Li-7 linewidths were also observed down to -20 degrees C suggesting highly mobile neutral aggregates of salt since this system is non-conductive. In the copolymer C16O1O5(21%):LiBF4 (1:0.7) the linewidths were even narrower down to -70 degrees C with weak temperature dependence. In all systems F-19 linewidths were significantly broader than Li-7 linewidths. The complex plane plots obtained by impedance spectroscopy exhibit characteristic minima identified with 'grain boundary' resistance and, following heat treatment, minima with weak temperature dependence identified with 'internal crystal' resistance, R-i, and conductivities, sigma(i) >= 10(-4) S cm(-1). Four-component mixtures of copolymers CmO1O5 and CmO1O4 with LiBF4 and 'salt-bridge' poly(tetramethylene oxide)-dodecamethylene copolymers gave conductivities of ca. 4 x 10(-4) S cm(-1) at 20 degrees C with weak temperature dependence. A novel carrier-hopping mechanism of lithium transport decoupled from side chain melting in the crystalline state is postulated. [GRAPHICS] (c) 2007 Elsevier Ltd. All rights reserved.