PVDF-PAni blend: a free-standing film with variable electrical resistance

Films made of a blend of polyaniline (PAni) and a nonpolar polyvinylidene fluoride (PVDF) polymer matrix were obtained by the mechanical mixing of both, with subsequent melting and quenching. Using the current versus voltage (IxV) measurements, the percolation threshold (concentration in which some conducting particles are connected to form at least one conductor path, related to one direction of the film) was determined to be between 40 and 45 % in volume along the surface. Related to the film thickness, a small amount of PAni (0.5 % in volume) was enough to transform the blend in a conducting material. Strain-stress tests indicated that a small amount of PAni can reinforce the polymer matrix. Furthermore, the immiscible blend obtained changes in its electrical conductivity, according to the pH of the solution in which it was immersed, indicating the possibility of the real application of that material as a resistor with variable electrical resistance.