Fabrication and Properties of Polypyrrole Nanocylinders

Abstract

Polypyrrole nanocylinders were fabricated by chemically synthesizing polypyrrole within the pores of nanoporous polycarbonate particle track-etched membranes and alumina membranes. The morphology of the nanostructures was characterized by transmission electron microscopy and scanning electron microscopy. The polycarbonate membrane-templated nanocylinders were cigar-shaped, with the diameter at the center being up to 2.5 times the diameter at the ends. The nanostructures produced in alumina membranes were linear aggregates of blobs. The electrical conductivity of the nanocylinders was measured by leaving the nanocylinders embedded in the insulating template membrane and measuring the trans-membrane resistance. The smallest diameter polycarbonate membrane-templated nanocylinders exhibited a slightly lower conductivity relative to the larger diameter nanocylinders. The temperature dependence of the resistance with and without the application of a magnetic field was in accordance with Mott variable range hopping at temperatures above 5 ± 1 K and Efros-Shklovskii variable range hopping at temperatures below 5 ± 1 K. Based on the measurements in the Mott regime, the localization length, the density of states at the Fermi energy, and the temperature dependence of the average hopping distance were calculated.