The electrical behaviour of hybrid poly(ethylene terephthalate) films containing localised percolating networks of silver nanoparticles separated by pure polymer is studied The films resemble an array of parallel wires in the submicron range and thus exhibit anisotropic conductivity In the high conductivity direction at low amplitudes the films show Ohmic behaviour while at moderate voltage non-linearity and a decreasing resistance is observed The samples were found to heat up during the measurements and the deviation from Ohm s law coincides with the Tg of the polymer Microstructural analysis of the samples revealed an irreversible agglomeration of the particles at moderate voltages leading to the formation of filaments with higher metallic character than the random particle network (C) 2010 Elsevier Inc All rights reserved