Abstract
We have studied thin films of thin and thick wall template synthesized polypyrrole microtubules. We observe a crossover from three- to one-dimensional variable range hopping in our samples at low temperatures. Our results clearly indicate that the geometry of the microtubules has an influence on the conductivity. The transition temperature from three- to one-dimensional variable range hopping shifts to lower temperatures when high pressure is applied. The results are discussed on the basis of the geometry of the microtubules.