Investigation of the conductivity properties of Langmuir-Blodgett films of pyrrole derivatives

In this paper, we present conductivity measurements made on Langmuir-Blodgett (LB) polymeric films obtained from pyrrole derivatives (3-hexadecyl-pyrrole and mixtures 3-hexadecyl-pyrrole/pyrrole) and deposited onto interdigitated structures designed ad hoc for electrical measurements on planar structures. Step response and voltage vs. current characteristics are reported and discussed, with particular attention to linearity and stability; from these data, the resistivity values of both types of film are derived. The results show that monolayers obtained from the mixtures are by far more conductive (four orders of magnitude) than pure 3-hexadecyl-pyrrole (3HP) multilayers, and that their electrical behaviour can be easily related to a pure Ohmic behaviour, while the 3HP multilayers cannot be considered as pure Ohmic components.